Carbon In My Skin. These Wounds, They Will Not Heal.

[@EatingCtrlV]

It's shocking that this is the first time anyone has looked into this issue given how common these types of materials are.

[@truantray]

Commerce over health is shocking? Anyone who works with CF has to wear PPE, breathing any fibrous material is as bad as asbestos. More shocks: printing resins have really toxic monomer compounds no one talks about. Fibers embedding in lung tissue causing chronic inflammation is how people get lung cancer, fibrosis and silicosis.

[@NathanBuildsRobots]

How the f*** am I supposed to sell you a 200% more expensive spool of filament if you know what’s in it??!

[@skunkprints7952]

@@EatingCtrlV that’s exactly what makes NBR awesome. It was under our noses the whole time and he put it out there so others can be “definitively informed!”

[@EatingCtrlV]

@@NathanBuildsRobots I'll spend 200% more on filament that you recommend as safer than others at this point.

[@TheOneAndOnlySatan]

In Nathan We Trust ! Cf filaments 📉

[@ericlotze7724]

Instructions unclear, made Asbestos Reinforced Filament

[@NathanBuildsRobots]

www.instructables.com/3D-Printed-Snorkel/?amp_page=true

[@ericlotze7724]

@@NathanBuildsRobots Now we’re talking! (sidenote if i remember correctly if you get the length of the pipe too long on snorkels you can mess up your lungs so *ye be warned* !)

[@TheSuperDuperLS]

I love inhaling Asbestos.

[@orbita1]

Yo how is that possible out of interest? ​@@ericlotze7724

[@technoman53]

I would not be surprised if there’s cheap “glass fiber” reinforced filament from China that’s actually asbestos reinforced.

[@gruvinnz]

I have a microscope. I also now have carbon and glass fibre stuck in several of my fingers! THANK YOU for bringing this to our attention!

[@NathanBuildsRobots]

I guess you didn’t want to take my word for it 🤣 But it’s much better to see this sort of thing for yourself than to take someone’s word for it.

[@gruvinnz]

@@NathanBuildsRobots One does not truly know 3D printing until one fights its fibres!. :p I also wanted to see how effective acrylic clear coating is. Even thin coats from an artists's air brush are surprisingly effective.

[@TheCablebill]

When it comes to environmental and materials hazards, we are typically oblivious by default. History repeats.

[@RonanPaixao]

Now imagine what's inside your lungs...

[@monad_tcp]

As long as they're not stuck in your lungs, it should be fine.

[@ShirozawaDesura]

Me *looking at the spot in my palm where I accidentally stabbed myself with a mechanical pencil when I was a child and still has the mark*: Yeah I’ve kinda noticed.

[@jamesg3713]

YES I KNEW I WASNT THE ONLY ONE

[@plinker439]

i been stabbed in the palm by a kid like 35 years ago and the graphite tip yet stucked in my palm. :) Maybe it slowly absorpted or some tissue case growed around it, i had no any problem with it at all, it's just carbon anyway.

[@oliverer3]

lol I still have a pencil tip in the center of my right palm and it's been at least 10 years.

[@DARKredDOLLAR]

My only tattoo.

[@LeafBoye]

​@@plinker439your body turns the cells around the affected area solid creating a little barrier around it so it never leaves

[@DrJuanTaco]

Embedded into the skin isnt a big deal you're covered in about an 11 layer barrier of dead cells before you get to the first layer of living dermis, and you shed outwards. The real problem is probably all of that that gets into the lungs.

[@K3Techs]

Few enough people seemed to mention this... Considering the size of the strands embedded in the skin after the test there's zero cause for concern in touching the parts. Anything in there is just gonna fall out while exfoliating. I'm more interested in knowing whether any of this gets airborne or whether parts can shed a significant amount of carbon filament particles in their surrounding environment.

[@ericp.5533]

Someone in the comments suggested using a fan and some kind of filter to test for fibers in the air. I'd like to see that too!

[@corvusmalus9263]

Yeah, it is just an irritant for the skin, and that only if you get large amounts into the skin.

[@quercus3290]

@@K3Techs I worked as a fiberglass laminator for many years, the strands become airborne very easily, you should wear a mask at all time when handling it.

[@K3Techs]

@@quercus3290 true, sheets or rods of carbon are the same. But once encased in molten plastic I assume dust is significantly reduced

[@benrampolla1415]

For what its worth, if you have a memory foam mattress, its embedded with fiberglass for fire safety. It wasn’t a problem with my bed until I took a factory mattress cover off (which had a zipper but according to the manufacturer is not intended to be removed) but I’ve seen a lot of memory foam mattresses with fiberglass sticking through the manufacturers covers. Not saying filament isn’t a risk, but there’s probably larger sources that you don’t even know about. Education is the solution imo- fibers have a risk, and knowing when a product contains them and how to handle them safely should be better disclosed.

[@NathanBuildsRobots]

Hooooooollyyyyyy shiiiii. That is insane. I always wondered why memory foam pillows and blankets have a special case

[@SianaGearz]

@@NathanBuildsRobots If they can guarantee that the glass fibres are the right thickness to be flexible enough and sustain the load without fracturing, and long enough to not become airborne, they can potentially certify the resulting material as safe. I wouldn't necessarily trust the material without testing it myself and being convinced that a suitable test protocol is in place, but fundamentally it is possible.

[@_droid]

Yikes. I didn't know this either.

[@WhatWillYouFind]

@@NathanBuildsRobots It goes without saying, don't be stingy and cheap out on your sleep surface. ;l

[@jupitersky]

It is 100% a problem, we once had a mattress cover degrade to the point where the fiberglass was wearing off and irritating the skin.

[@cexinho]

next step, get a very thin but mildly dense piece of a filter, reverse the flow of a part cooling fan and place the filter there to then see it under the microscope so we can see what particles are actually flying around mid print

[@JeronimoStilton14]

True

[@ericlotze7724]

Adhesive tape or that design for the 3D Printed Pollen Collector someone pit on a bike may be an interesting way of measuring these things as well. Also UV Lights make some Microplastics fluoresce and be more visible. Granted look for existing scientific/industry standards too, heck may even be some ISO standard!

[@fishHater]

@@ericlotze7724only problem with iso standards is they make you pay to see them

[@ShadowlordDio]

​@@ericlotze7724then endoscopy to check fibers in the lungs 😅

[@TheGameGuruTv]

That stuff, in ya lungs, delicious

[@GhostlyGnome-iq9wl]

I worked in the asbestos abatement industry. It would be interesting to see a professional air quality report conducted on a 3d printing room. The air quality technician would set up a small air pump or two in your room and collect samples over a day or two. After witch an analysis is conducted at a qualified lab to determine if the air quality is acceptable or not due to the ppm of airborne particulates being to high. A quick search led me to a Scientific America article from 2008 "Study Says Carbon Nanotubes as Dangerous as Asbestos". Although most filaments are made with carbon fibers, I think is important to consider. I think your doing great work Nathan. I am way more interested in this type of content then printer reviews so I think your decision to change your focus is a solid choice! Your videos with the printer you built set my creative imagination a buzz.

[@Boofi-quat]

I wonder how long the industry will continue to deny that this is as bad or worse than asbestos. Amazing.

[@blu_indi9333]

I recommend looking into reports done at injection molding companies. They produce an exponentially more parts than the 3D printing "industry". They use the same plastics. The companies will have these reports since it is part of required audits and OSHA.

[@blu_indi9333]

​@@Boofi-quatis nowhere near it.

[@Zewwy_ca]

You don't want to know if you have a newer resin printer. (It's bad)

[@Boofi-quat]

@@blu_indi9333 My guy we are living in a world where industrial safety research study groups are hired by the industries themselves. You trust them?

[@rupertmiller4718]

Take a tip from boat builders and F1 engineers, they wear gloves when handling carbon fibre and glass fibre. 50 years ago they didn't but they have learnt. Actually the fibres from woven carbon are too thin to cause a wound but can become embedded.

[@jsands26]

That’s just to protect the carbon fiber from the oils on your hands. If you get oil all over the fiber reinforcement, the resin won’t bond to it as well. Oil isn’t great for prepreg either.

[@bluesteel8473]

Ever since I got into 3D printers, I learned about the micro plastic problem and decided to mitigate it by isolating my printers in a garage with vents sucking air out. I also wear a p100 respirator anytime I’m in the garage if they’re running. I only use pla+, Lw-Pla, Petg, and tpu. I’m glad you made this video. It’s hard to avoid plastic exposure since it’s literally everywhere and in/on everything. But you can’t 3d print a new pair of lungs.

[@NathanBuildsRobots]

Yet 🫁🧵

[@bluesteel8473]

@@NathanBuildsRobotslol.

[@bluesteel8473]

I’d add, wearing gloves can’t hurt. I also burn off the tiny strings of plastic that are typically on my prints with a lighter or candle. I figure it’s better than mechanically cutting them off since they can float around in the air.

[@stealthwang]

@@bluesteel8473 where do you think the soot goes?

[@ericlotze7724]

@@stealthwangsoot should at least be a bit less permanent than Microplastics. I tend to burn, then wash with water+dish soap (in *theory* any residue is washed off) Precision Temperature Control Heat Gun and/or Inert Gas is my dream for print thermal post processing, can set it to the *exact* melting/softening point etc

[@sadboidex6106]

these videos need to go viral. the 3d printing community needs to be aware. wheres Joel 👀

[@NathanBuildsRobots]

Joel doesn’t simply appear, he has to be summoned! JEEEEOOOOOOOOOOOOOOOOOL

[@ericlotze7724]

@3DPrintingNerd 🔥a w a k e n🔥

[@robertmiles9942]

Why would they not be aware? It says "carbon fiber" right in the description when you buy filament. I really don't know why people use the shit it doesn't make stronger prints anyway

[@Shadow27374]

Carbon is not toxic

[@joanyadhatan]

@@Shadow27374 neither is the knife (in your chest)

[@ath_greek]

a channel that cares for your health 🙏

[@NathanBuildsRobots]

Next up, diet and excercise!

[@TheFish711]

For a human skin analogue. Try using something made of silicone. Preferably a lighter tone for the carbon fiber and perhaps a darker one for glass fiber. That might help with visibility. You could even cast one in a mold made of one of your fingers to make sure the surface of the analogue has a similar texture.

[@AlexRian_]

I have extensive experience with composites and already shared my experience regarding 3d printing CF filaments under the last video. So far the information indicates the following: To enter the lung and trigger serious issues (such as asbestos), fibers must have a diameter of less than 3um and a length of 10um or more (yes, there is a minimum length required - not a maximum as is the case with the diameter). Mechanically processing carbon fiber composites fractures the fibers and can contain some fiber fragments that can enter the lung. The ratio of fibers that can enter the lung and those that cant is a lot better compared to asbestos. So the risk should be lower and that is the result shown in some studies as well. The plastics used in 3D printing seem to have a worse bonding to the fibers, so when printing and handling the parts, the risk of fibers breaking up into thin and fine fragments that can enter the lung is likely a lot lower. Sanding 3D printed CF parts might also produce less dangerous dust, because the milled carbon fibers used in the filament will be freed from the plastic before they break apart. There are no solid studies on this, so this is still a bit theoretical and based on some sparse information and a general understanding of the properties of carbon fiber composites. Glass fibers are even thicker than carbon fibers - so even farther away from the 3um threshold below which the fibers could enter the lungs. On top of that the general consensus is that mineral and glass fibers have a rather low persistence in the body and lungs. They can be dissolved and removed by the body. this removes the extremely long persistence in the body that is assumed to be a major factor in the mechanism to create cancer. Therefore glass fiber parts are very very likely a lot safer than carbon fiber and carbon fiber itself is a lot less critical than asbestos. It is still a good idea to protect yourself when working with carbon fiber filaments and parts, but according to current knowledge it is by far not on the same level as asbestos.

[@PostMeridianLyf]

When I was a kid my asian friend said 'don't touch the top of the bamboo' as I had already placed my hands directly onto the top parts of the plant. Millions of little fibers entered the palms of my hands and I couldnt touch anything for a few days from the pain. I laugh at it now but wonder if there are better alternatives for the fibers being used in your filament

[@MiGujack3]

Bamboozled

[@ZentaBon]

@@MiGujack3hehehheheh

[@rekt6408]

The particles are small enough it isn't harmful to us thanks to our skin doing its job. The real question is if these fibers are floating around and getting in our lungs with the part cooling fans. Thats where we could potentially get major health issues. Looks like I'll be wearing my respirator I use for my resin printers for all the printers.

[@BESTofAlp]

This topic is more important than anything else in 3d printing.

[@ajlbeer]

Great job, thanks for doing this. Resin printing is fascinating to me in terms of a lack of regulation, and how it's so common now for engineering grade chemicals to be handled by consumers with zero education on safe handling. Additionally, the idea that so many people are selling their prints on etsy and other marketplaces to unsuspecting customers. A friend of mine bought some 3d printed super hero figures on a market place that slowly began to crack and then leaked uncured resin on a mantle in his kid's bedroom. It's a free for all out there, and nobody has even said "buyer beware".

[@johnandrews9433]

The MSDS is there for anybody to read, the fact that people don’t is their own fault.

[@W98Dragon]

Unfortunately too many people that don't really know how to properly print and cure resin sell their stuff online, or claim to be experts

[@shaunybonny688]

Regulate me hard daddy.

[@Megasteel32]

@@johnandrews9433 where? they're not provided with the materials you have to dig for them. don't be a useful idiot.

[@NathanBuildsRobots]

I’ve done resin printing once and I knew to not trap liquid resin inside the part!

[@Taiko_Drum]

I get it, the title, Linkin park, Crawling. Nice one LOL

[@atriyakoller136]

Yeah, I don't handle carbon fiber in any way, but the reference made me watch the video 😅 it's a good one

[@Internetzspacezshipz]

How in the hell did I not catch that. I took it way too literally…

[@ATruckCampbell]

Thought it was just me.

[@akiraic]

the only reason I clicked the video. Surprised to see how so few got it

[@deucedeuce1572]

Reminds me of those fuzzy cacti, where you touch them and they feel fuzzy... but the moment you touch anything else, the tiny needles from the cactus get embedded into your skin and hurt really bad. Then you're screwed for a week or so until the needles all work their way out.

[@JanKopanski]

Things make so much more sense now. Everytime I've handled CF filament my hands were always a bit itchy and I thought I was going crazy but this explains it.

[@paramedic4176]

Same but with my throat... Uh oh

[@jaykiller4510]

Same but with my azz

[@MrDanDizz]

This needs more attention, many are still saying stuff like "PLA IS SAFE" and other fillament, but who actually knows what the chinese manufacturers put in the fillaments and how much they really care about health effects from residue etc. Just like everything else, do your own research, and be smart. Great video, we need to push this topic more out there for our own sake. Still see too many people running even 3d print farms without any ventilation, enclosure or anything. Research doesn't have a long term effect results yet.

[@brokenbizkit]

Exactly what i was thinking since i started 3D printing. Who knows what kind of additives are in PLA? Even the cf rods of the bambulab printers are losing splinters that go into the air. I tested it under a microscope. Nobody talks about it...

[@MrDanielsahne]

PLA is probably one of the few things you don't have to worry about.

[@brokenbizkit]

@@MrDanielsahne True, but about the additives in it

[@JJFX-]

I wouldn't worry much about standard PLA but hard to say if the additives used in some of the fancy variants could be problematic at scale. Regardless, there should always be some ventilation or at the very least a decent filter setup. Those who print ABS/ASA should absolutely prioritize this. Do NOT mistake "low odor" ABS filaments as being any safer to be around.

[@mrraimundo130]

Just printed a gift with the Bambulab PLA-CF and gave it to a loved one. Then I saw this video, like 20 minutes later. Needless to say I took the gift back and applied double coating of hair spray - for the lack of a better alternative. Thanks for providing this info!

[@k.a.m3683]

it's too late carbon fibers are already embedded in their hands

[@Jimmy___]

Good work Nathan. I hope the industry reacts to this quickly. Manufacturers can be forgiven for not knowing this would be an issue, but once the info is out we should judge them on their response.

[@jexrutin69]

Manufacturers only think "can we?", while they should be thinking "should we?". Profit and shareholder revenue first!

[@alexanderdiogenes8067]

re: Human skin analogue: I know that tattoo artists practice on grapefruit/oranges

[@ge2719]

probably better and less messy than the other thing people use to practice tattooing on, pork skin.

[@raymondmalone16]

Maybe a banana too, I believe surgeons practice incisions and stitches on them. Plus the fibers would be easier to see on camera with a yellow background.

[@EversonBernardes]

@@raymondmalone16 banana peels are also often used by tattooists.

[@Jakuzziful]

I think oranges will fume or squirt more than a banana. I‘ve never heard about citrus fruits for practice but about bananas.

[@GeddyRC]

@@ge2719 I think they're called "pigs".

[@samuelbentz]

I’m glad you’re moving to more project and exploration/experiment based content. I’ve really been enjoying the content lately.

[@ginjabrad]

My mind is blown, this is the first time ever hearing this about 3d printed stuff. Thanks for getting this info out for public safety.

[@behrens97]

I work in the aviation maintenance industry and it is well known in the industry that carbon fiber can be very dangerous. Getting it on your skin is not too hazardous but if it gets in your bloodstream it is poisonous and can be deadly. We had a technician working inside an aircraft in the same area for days and rubbing his arm on the edge of a carbon fiber composite panel until it caused scrapes through his skin. A couple days later he suddenly became ill. He then spent a week in the hospital for carbon fiber blood poisoning and was close to death. He did make a full recovery and developed a phobia of carbon fiber and I can't blame him. I honestly would not use carbon fiber infused filament but that's just me cuz I know the risks and an actual story

[@iKidTutor]

Nobody's talkin about the linkin park reference😂 fr

[@nesthi]

I got ya! LOL

[@jules47127]

Seriously yes, I had to scroll way too far to find this comment

[@peterpolus5272]

The comment I was looking for! 😎

[@thatonesnowboarde]

White and many lighter filaments has Titanium Dioxide which are used as whitening agent. This is why white can wear out your nozzle faster

[@imafiretruck7454]

Absolute madness that same ish is also used in pharmaceuticals, cosmetics and even foods to make those white colors really pop for us

[@thatonesnowboarde]

@@imafiretruck7454 and tooth brush... ya crazy times, make sure you only use clear soap.. that doesnt have a bunch of chemicals

[@inhumanguy]

I bought a Bambu P1S in large part for the enclosure and filtered chamber fan. been trying to be kinder to my lungs since quitting smoking. using a respirator more, n95s when it's hazy out from wildfire smoke, good filters in my hvac and vacuums. we're surrounded by so much fine particle pollution, it pays to cut down on exposure whenever feasible.

[@NathanBuildsRobots]

Congrats on quitting smoking, probably more important to do that than any of the other stuff!

[@Tgspartnership]

thank you for getting in to this, safety of filament must have been an open question for some time. if plastics are as potentially harmful as some of the science suggests, this stuff is well worth knowing. how about some 3d printed breathing apparatus?

[@NathanBuildsRobots]

Only if I get to make it out of CF-PLA

[@TheOneAndOnlySatan]

Ah, new print project! I don’t think anyone’s managed to print a casket yet.

[@RinoaL]

I'm so glad you've been showing this. I had a roll of filament given to me which has carbon fibre in it and had almost used it for a few commissions. Thankfully they would have been structural pieces for automobiles and such but still.

[@DavidRobertsonUK]

I think it's actually a dangerous assumption that regular FDM printing with e.g. PLA, PETG does not produce airborne microplastic particles

[@xsweetxvampirousx]

That title brings back some old memories... But it the end, it doesn't even matter.

[@tylercollins4125]

I read it to the melody of Crawling automatically lol

[@iKidTutor]

Same haha

[@TheOriginalGabberjaw]

Doubt many people noticed 😅

[@spacecowboy07723]

Rip lp

[@buiItnotbought]

Carbon in my skin. These wounds they will not heal. Clear coats the way to go. Time to order another reel.

[@AuxiliaryPanther]

I was an EM in the US Navy, and I did lots of maintenance on brushed electrical machines. I had carbon dust embedded into cracks on the sides of my fingers from 4 years (the cracks were from manually turning nuts and bolts with my thumb and side of index fingers). It wasn't until 6 months after leaving the Navy when my skin replaced enough layers to clear it up.

[@TennageToaster]

Great video! I'm all for knowing what's in my filaments and the suggestion to coat fibrous filaments after printing. I've been printing in glass fiber ABS and definitely feel the splinters. Keep it up!

[@HE-162]

I’m surprised you didn’t mention the fact that we get exposed to all sorts of nasty stuff every day. Safety is about moderation. Cf filament doesn’t produce a genuine risk to anyone unless they’re working in a print farm with tens or hundreds of printers working with CF every single day. CF, Fiberglass, Asbestos, etc, pose a cumulative risk when inhaled. You would have to breath a lot of those fibers that shed off into your finger…which would be extremely difficult judging by how much shed into your skin. This is far safer than resin printing, whose dangers are also super overblown. Resin printing isn’t going to kill you, long term exposure simply risks developing an allergy to it. For most people, that isn’t likely to happen unless they’re bathing in resin or breathing it in constantly. Just rig up the printer to exhaust fumes out a window or use strong carbon filtration, and wash any resin you may get on your hands promptly. If you wanna use gloves, more power to you, but if you’re mindful of keeping it off your skin and washing it off when it does, you’ll be fine. 99% of safety is common sense and mindfulness of the risks, not fear mongering and suiting up like a hazmat worker. Same with printer VOCs. They’re not that dangerous, mostly just unpleasant to smell. Fresh air or a simply dryer vent out the window is really about not smelling the unpleasant smell and quelling fear. People breath in nasty chemicals all the time without thinking twice about it, stuff that’s far more dangerous that the VOCs from printing abs in your garage without ventilation. These materials really pose very little risk in the exposure levels hobbyists will encounter them. Its an oversight to not make that very clear, and instead make them sound extremely dangerous for the hobbyist leading to people in this very comment section saying they’re going to abandon them outright as if they’re working with caustic acid. Meanwhile those same people cut lumber without a mask(silica), cut drywall without a mask, sand their resin prints without a mask, use cleaners in the home without a respirator, clean the dust off their calipers when they change their brake pads without a respirator, smoke cigarettes, drink booze, smoke weed, eat fast food, etc.

[@mscrawford87]

I am just curious what your educational background is to make these statements with such authority? Not trying to downplay you, I am just getting into 3d resin printing and there seems to be so many extreme opinions on either side of this safety debate and want to know the answer from someone who actually knows what they are talking about. So, what is your occupation? Chemical engineering? Chemistry? Materials science? Or are you just a hobbyist who might want to downplay the risks? So far what I've read about resin is that its considerably more toxic than household products and that they should be handled much better than what the average hobbyist is doing.

[@HE-162]

@@mscrawford87 nope, just a hobbyist who took the time to properly research the dangers via the limitless scientific studies and documentation available on the chemicals and materials(like cf and fiberglass) in question. I also am a blue collar worker who works with things like carbon fiber and dangerous chemicals regularly(and takes appropriate caution when necessary). Ignore what the 3d printing people say and go ahead and research the actual compounds and materials in question. Just like you said, there are a lot of extremist, sensationalist opinions that get parroted over and over again by people in the hobby who don’t bother to lookup the science. Great place to start is the msds. Exposure to dangerous chemicals and materials is almost always a question of exposure volume. Alcohol is a dangerous chemical that people use to sanitize wounds and their hands, regularly, but technically it is harmful. Cutting/sanding wood releases silica, and even lifelong carpenters don’t typically get silicosis. When was the last time you dealt with fiberglass insulation, and did you wear a tyvek suit with respirator? Does anyone? Technically it’s harmful, but mostly it’s just an annoyance unless you’re working with it every day for years. The stuff we encounter when 3d printing is essentially harmless with the most basic precautions, but people blow it out of the water. Running a print farm as a full time job and spending 8 hours a day for years may pose a risk, but probably not. Yes, resin is toxic - just wash your hands promptly and wear rubber gloves if you want a little extra peace of mind. The most basic safety measures are more than sufficient for this stuff. Make sure your resin printing space is well ventilated, preferably actively ventilated. My resin printer has a pc fan attached that connects to a dryer hose to vent out the window, and I lined the chamber door with window foam to ensure an air tight seal. I never have the odor of resin. I make sure to let my platter drip excess for a while before placing it in the cleaning station, so that it doesn’t drip resin onto the table when I remove it. If I get some uncured resin on my skin, I immediately wash it off with soap and water. I typically have rubber gloves on, but sometimes I don’t. I don’t print ABS or other fume producing filaments, but if I did, I’d connect a duct to the chamber and run it to the window just like the resin printer. If working with CF, I put gloves on, and don’t give it too much thought, because the volume of exposure to this stuff is so minor that it’s not a problem. There’s no need to be scared of this stuff, there are no crazy dangers of exposure in hobby 3d printing, the health risks are basically zero even without taking simple precautions. People make such a big deal about resin, but if they bothered to research it, they’d know that the danger resin poses is simply the development of an allergy to it…for a very small percentage people…after a lot of exposure. There are some people who are naturally allergic to it, which is a different story. Just use the same kind of caution you would use when cleaning your kitchen or bathroom with chemicals, working with serious glue or solvents, etc. As long as your printer isn’t in your living room printing 24/7, you almost certainly are exposed to more harmful things every single day. The extreme fear and danger people seem to push about 3D printing is totally overblown and unnecessary, and it only takes a half hour researching the practical harm these chemicals and materials pose to see that. Ignore the 3d printing people, and just look at the science, of which there’s a limitless supply of online.

[@Yoshikaable]

Cutting lumber doesn't release silica. Maybe you meant engineered quartz counters?

[@HE-162]

@@Yoshikaable working with certain kinds of wood absolutely does. I was very surprised to learn it as well. Apparently wood contains pockets of silica, particularly hardwood like teak. Its concentration isn’t high enough to be of concern for the weekend woodworker, but its concentration can be high enough to degrade tools used in the commercial processing of hardwoods - and by extension, may pose a health risk for people who process bulk hardwood. Apparently some woods can contain more than .5% silica in its composition. Obviously anyone working with stone and rock needs to consider their silica exposure and proactively using ppe, as they’re going to exposed to a lot of silica.

[@GucciBodyBags]

Ive shared this amongst my friends. Ive thought this was a risk from the beginning but no one talked about it. Thank you for bringing this to light.

[@alexanderwoolley1623]

As for a human skin analogue, orange peel should be enough to accurately show these fibres penetrating ability, I'm unsure of how it will compare under a microscope, but I've switched to using oranges to test my knives when sharpening/dulling (creating a sharp edge, then stropping to round off the apex, and smacking it against the orange to test if it's blunt enough to be EDC carried, as opposed to hitting it against my hand)

[@pupc0ded]

i've had a HEPA & activated charcoal filter i 3d printed for my IKEA enclosure since i got my ender 3 pro way back when nearly a month into ownership. I didn't trust the rough textures, VOC, and smells of filaments to be safe whatsoever to breathe long term, and always ended up filler priming finished prints or clearcoating them. Really happy to see some investigation into this and confirming an amount of my fears.

[@InspectahPatio]

Using carbon to filter the carbon ahaha

[@brokenbizkit]

Nice! I thought i am the only hypochondriac in this 3d printing world. How big did you make this filter? Because the tiny ones that are already built into some printers are uselessly small.

[@ryv2582]

The title of this video “Carbon in my skin, these wounds, will not heal” would make a perfect metal song lyric

[@SophiaAstatine]

I mean, that makes sense.

[@WillPower311]

Thank you Nathan I really appreciate you are testing and showcasing the truth. I'm learning a lot from you

[@nameismetatoo4591]

7:11 I accidentally stabbed my palm with a pencil in 5th grade. 17 years later and the graphite is still visible under my skin.

[@Thunder_warrior]

Lfmao

[@afgncap]

I wouldn't really worry about that unless you are at the risk of inhaling. Epidermis is constantly flaking off and dead skin cells get replaced at a constant rate. These fibers seem to be small enough to get removed when skin naturally flakes of.

[@ericlotze7724]

5:50 For the most part yeah. I would LOVE for a proper doctor and/or Industrial Hygienist etc to chime in, but Asbestos/Carbon Nanotubes also have the issue of sharpness/barbs (which may be related to the elastic modulus you mentioned, but also maybe structure?) Also “bio-soluble” insulation being marketed led me down a rabbit hole so that may help you too! At the end of the day though yeah lungs are fragile, take care of them!

[@NathanBuildsRobots]

Doctors and doctors in training are expensive busy around these parts. I would love to have a conversation with a medical expert that specializes in the subject

[@marsgizmo]

This is a great video Nathan! 👏 Excellent work and would love to see more like this.

[@BoleDaPole]

Something as simple as a DIY contained vented enclosure can greatly reduce the risks involved with 3d printing, not to mention wearing the proper gloves, masks and glasses. Glad to see you're making topics on saftey because it's not discussed as much as it should be. 👍

[@Megasteel32]

there are no risks with FDM in terms of air quality when working with normal filaments

[@hrmny_]

​@@Megasteel32there are, it was even mentioned in the video But yes, it's a lot less with PLA than ABS or SLA printing

[@Megasteel32]

@@hrmny_ there aren't, if you do your own research

[@riba2233]

@@Megasteel32 there are with abs and some other specialty filaments (pmma, pom, pvc etc)

[@dangeary2134]

I used to work with fiberglass on occasion. I ALWAYS wore a respirator when grinding, sanding, or cutting any material that was some sort of plastic. Problem was, that in summer, it gets dreadfully hot in a full kit of PPE. When I did fiberglass, I had a roll of quality duct tape for the end of the operation. I wore gloves to keep the fibers and chemicals off my skin. The dust? I would use an air hose to blow the dust off my arms, then use the sticky side of the duct tape to pull all the dust off my skin. After that, a cold shower to get the bulk of the remaining fibers off, followed by a hot shower to wash the rest out of my pores. Never had even as much as a zit following this procedure. I did not work with this stuff as a profession, so I didn’t have much to worry about. If it WAS a profession, I would have definitely conditioned myself to wear the full PPE getup and get accustomed to it.

[@joannot6706]

Linkin Park reference for the title 👌💯

[@paladinkhan]

This is definitely something deserving of more attention, these materials should be handled with care. I know 3d printing labs in schools are more common place now, although maybe not using fiberous resin stuff isnt as common in the classroom. It would be very important understanding how much of an issue this is when it comes to air contamination, and handling materials as such going forward

[@LostInTech3D]

new macro channel!

[@NathanBuildsRobots]

I even spelled fiberous in the British way for the thumbnail

[@802Garage]

Hahahahaha excited British noises.

[@Freddy_Merckx]

It is really great that someone is also covering the risks of 3d printing! Another topic that came to my mind is the emission of potentially carcinogenic vapors which are produced by heating up the filaments. Many people have these devices in their flats or in their man caves where they are around and they don’t take care of a ventilation system how it would be realized in an industrial surrounding.

[@nathan22211]

The only issue I'm finding is a source for how dangerous these fibers in the filament are compared to those that some factory workers would get exposed to regularly. Mind you these fibers are tiny compared to the ones used in CF wraps or molds, and while Copilot didn't provide a source, apparently they can only get into your system by an open wound or inhaling. Which considering that they're mostly encased in plastic in this scenario, you're more likely to get them embedded about skin deep. Yeah my only guess would be to be careful handling them if you have an open wound, even though they should be filtered out by your liver or kidneys. And to run the part against a wet paper towel or under some water after printing. Also, FFS Nathan, don't use your own body for shit like this, use ballistic gel or something. In a professional lab setting, you don't use your own body for the experiment most of the time.

[@NathanBuildsRobots]

Anything with a long aspect ratio (above 1:3) can’t effectively be cleaned out of lungs. Particles below 60microns stay suspended in the air for extended periods of time

[@nosidenoside2458]

L copilot user

[@nathan22211]

@@nosidenoside2458 Google's search AI probably wouldn't be any better at providing sources for this. It might be worse than Copilot at some things

[@JJFX-]

As someone who primary prints CF ASA/ABS I very much appreciate this video and upset with myself for not giving it much thought despite being well aware of the dangers of traditional CF materials. Luckily I rarely need to post-process/sand my jobs but I'll be clear-coating everything moving forward.

[@killdozer3464]

I need everyone to stop using fiber filled nylons. Make the market crash. So I can buy it all on the cheap. Thanks, bye.

[@dasbuilder]

I just bought a 3d printed item for my coffee grinder and your video opened my eyes to know if the materials I’m using will chafe or come off in my coffee grounds. The product isn’t involved with the grinding process, but is a hopper/bellows setup.

[@tik2243]

Make sure your material is food safe. The tiny gaps in a 3D print are hard to clean and a spot for bacteria to stay

[@aware2action]

Now we need to be careful with any filament that is deemed abrasive on the nozzles🤔, Most likely all of them will endup with safety issues. Also what about if those abrasive stuck particles start reacting with solvents we use such as alcohol(as in a sanitizer), or other chemicals like nail polish (acetone)vapors, or paint solvents, gas, diesel etc? What is the potential for turning carcinogenic 😢. It is like an elephant in the room, now looking back. Unfortunately the genie is out, thanks to NBR for bringing awareness😅. Looking forward to huge clearance on these filaments. Now need to figure out an effective conformal coating/dip, to use all these goodies!😂❤👍

[@nucleochemist]

Ive been thinking about this a lot as I use CF and now GF reinforced filaments quite a lot. I'll still use them because of their unique advantages but I will use more clear coats on final products.

[@Get_yotted]

I work with cars, my lifespan has already been decreased by that

[@hebijirik]

Thank you for all the detail microscope pictures. You mentioned experience sharing so here is my experience with what it is like to handle extreme amounts of carbon fibers. Years ago I got to visit a small aircraft factory a few times (small aircraft, not so small factory). Some produced parts were fiberglass but most were carbon fiber. First a large room where they unspool the fabric onto a long table and cut out the needed shapes using templates. Diamond microteeth scisors were used but they went through so much fabric per day that one set of those most advanced most expensive scisors would still last maybe a week or two. (Or just hours when doing Kevlar btw.) The air in this room felt heavy despite ventilation running it through filters all the time. That is what you get when you cut several dozen kilograms of carbon fabric per shift. Everyone was wearing gloves, some people breathing filters as well but those were not mandatory there (at least not all those years ago). Then the wet layup rooms, not much on those. The handling of the fabric is minimal because the cutting shop prepared kits so the layup team only picks up the piece on top of the stack, places it in the mould and saturates it with resin, picks the next etc. After all layers are in then peel ply, breather, vacuum bag... Standard PPE was just gloves. If polyester resin was used instead of epoxy (typicall for large bucks and mastermodels) activated charcoal filter masks were used too. By far the craziest environment was the part finishing shop. The parts come out of the mould with excess on all sides that needs to be trimmed off with precission. Typically a rough cut with a vibrating saw or occasionally a router. Holes need to be drilled. Then all edges are sanded smooth and to the precise line with vibrating sanders and by hand. Basically if you wanted to create as much carbon fiber dust as possible this would be the way to do it. So the standard PPE for this was a full body suit that seals around gloves and boots, with a shroud over the head and full face mask with filtered air actively pumped into it. Despite all this protection after working there just one day you would start to feel irritation on your skin (experienced myself). After a week this is constant whenever you touch your skin with a wet hand (I only got two days but mostly fiberglass which they said was worse for the skin). It feels like sandpaper touching you. People working there were paid a lot higher than any other factory floor workers yet nobody lasted more than 6 months. The owner of the factory told me one of those employees when quitting said he will go back to working in a coal mine because that was easier. So that concludes my story about how dangerous carbon fiber handling can get. We will never get anywhere close to this with 3D printing. You would have to run a farm with hundreds of very fast printers all printing carbon fiber filled filament non stop to be handling the amount of carbon fibers per day that was processed by that aircraft parts factory in a single shift. Carbon fibers in a filament are certainly something to consider and maybe not use it unless the application really calls for it and the finished part will not be directly handled by naked skin in its use. If it is a mechanical part burried inside a robot somewhere it is no problem in my opinion. And unless you have to handle it daily I would not think special setups are needed. I will apply similar precausions like when handling some paints or glues: limit my time of exposure, ventilate the room well. If a factory processing 50-100kg of the stuff per day did not see people ending up in hospital after a month, if a friend working there for years is now still fine 10 years later, then being around 100g of it in 1kg spool for a day or two twice a year will probably not have any measurable effects on me unless I do something trully stupid like put the printed part to a belt sander and breath in the dust on purpose or something.

[@skunkprints7952]

Nathan Builds Robots is the definitive source for 3D printing news and information!

[@NathanBuildsRobots]

😇

[@vipertube7182]

Thanks for the informational video. But I would like to point out what make asbestos more dangerous than carbon fibers and glass fibers is 2 fold. 1. Asbestos is takes much longer to break down in the lungs enabling them to cause more harm. 2. The fibers that make asbestos really dangerous are long and Very thin. Orders of magnitude smaller than the smallest glass/ carbon fiber that would be used in a filament. However both are still dangerous to inhale. But as far as risk it generally would not be seen any where in the same ballpark as asbestos. With the exception of carbon nanotubes with wouldn’t be in this setting.

[@metallsimon]

15:44 i really wonder how much microplastic comes from clothing and how much plastic is in the air or hopping around as dust bunnies

[@ericlotze7724]

Get a UV flashlight, it was VERY eye opening for me! I fear using it to see what the soil looks like at my work (where i weed wack with neon orange nylon line) Pros: Glowing Soil Cons: Potential Health Risks also *lowkey uncleanable litter that will probably end up in the fossil record* 💀

[@widget5963]

@@ericlotze7724 Eh, bacteria will figure out how to eat it. ...just maybe not in time for any humans to still be around to benefit.

[@ericlotze7724]

@@widget5963 the one issue i have with this too is IF microbes figure out how to eat it then it no longer has that benefit of being “indestructible” to an extent; it will rot like wood. Good for some things, but having a material that doesn’t rot CAN be very useful (also a LCA looking into emissions/pollution etc from paint/coatings and so on as a comparison would be neat) I was going to write some bit on this of not just “biodegradable” or not, but also how fast it biodegrades, instant like paper or years etc

[@WEEWOO2]

Very interesting. I imagine as some have already mentioned that on the skin might not be a huge issue but if you print things for an income and have a print lab, ingesting fibre over time could be a big concern without safeguarding like gloves, masks, good ventilation and regular cleaning of the lab.

[@MichielDijk93]

I have never used these kinds of filament as of yet, but this totally does not surprise me. I used to do competitive (recurve) archery some years ago where the most common type of arrow shaft was made of a aluminum-carbon composite. Now those fibers probably ran lengthwise along the shaft, but sometimes arrows break. Or get damaged. It was always made clear to just throw away a damaged arrowshaft and to NEVER touch anywhere near the damaged part of carbon fiber, precisely because of how easy it is to penetrate the skin and that it doesn't break down in the body.

[@wesleyhempoli5548]

An* aluminum

[@Docgy]

This is a very great description of the big issues. This is definitely a new micro plastic issue in our future.

[@grantcatdone3417]

I've unironcally had the dream of makings an asbestos and resin cast fidget spinner just for the fuck of it but for now a cf nylon printed one will do. Maybe once I'm like 60 and can't develop asbestosis I'll make it

[@FireDFPV]

I used to get skin inflamation due carbon fiber dust (quick hand filing carbon fiber without a glove on one hand). Luckily it is just a small area of my hand. The inflamation grew up for serveral weeks if not a month until it looks like dermatitis. A doctor gave me a steroid based ointment to reduce the inflamation. It has got better but once I stop using the ointment the inflamation slightly return. Finally the inflamation is gone but that skin area appeared to be darker than usual for a few week later. Fortunately it is normal now.

[@Stellar-Nucleosynthesis]

The first thought that came into mind was "but what if I rub my eyes?"

[@NathanBuildsRobots]

Eyelid epidermis is only 0.05mm thick 👀🫣

[@dancoon7653]

Brillant video and something I'd never given a second thought too. I've never used any of these fibre filaments (never felt the need) but these risks really should be looked it. Keep up this sort of information as it's good to know about and not really covered by anyone else. Thank You.

[@josephpk4878]

Again, CF fibres less than 1mm in length and loosely distributed in a polymer is a pretty useless application of CF. - it adds zero structural benefit and is more of a gimmick IMHO. Your biggest risk from CF is if you inhale it, so every roll should have a health warning on it and you should always have a mask on when using it - especially when you're cutting it. Cut a sheet of CF while there's a bright light on it and you'll see the stuff everywhere in the air.

[@NathanBuildsRobots]

Good thing my A1 cuts a piece off every time I use it 🥸

[@logicalfundy]

Well, the reason why I used CF is because it warps less when printed. Looks like I'll be phasing it out and looking into other ways to combat warping. Unfortunately I have a Prusa so any serious attempt to raise the temperature inside the enclosure will likely require me to re-print and install all of the printed parts in a material that can tolerate high enclosure temperatures.

[@HoloEN_GawrGura]

Plastic engineer here: The fibers do add stiffness, reduce warping a lot and increas thermal stability. These materials have been used in injection molding for decades for a reason and we have proof in the form of numerous material tests and simulations. Materials reinforced with fiberglass and/or glass beads, like PP-GF or PA-GF are used in injection molded parts for anything from cordless drills, medical and food related equipment, to automotive structural brackets and body panels. Fiber length for these materials is way below 1mm, especially once it's in the mold.

[@HoloEN_GawrGura]

@@NathanBuildsRobots This is mostly a problem with abrasive cutting and grinding methodes used for cutting continuos fiber materials like carbon fiber or fiberglass laminates. The A1 shears off the material, that doesn't really create any more dust than just handling the filament itself does.

[@Patrick-857]

It has benefits. Like allowing any printer to print nylon with just a nozzle change as opposed to all kinds of challenges with normal nylon. Plus it looks cool, and is significantly more rigid, with better thermal stability. However I'm going to think twice about using it without a clear coat.

[@42earthling]

Hey Nathan, this is very valuable information for anyone who wants to start 3D printing. Thank you for doing this research and making these videos. :)

[@DrLesterTheSmith]

@nathanbuildsrobots out here sacrificing his body for science!

[@roboman2444]

Also something to note is how the fibers break down over time. Wood fibers will easily break down, so having a few embedded deep in your skin isn't as big of an issue. Glass fiber or carbon fiber wont break down on their own. Does your immune system start to break down glass fiber? This is one reason why PLA is so nice. It will break down over time. Is there a glass bead reinforced filament you can test?

[@triumphant39]

I think that your body pushes stuff like this out. Certain substances can help with that, like drawing salve or ointment. In any case if it does stay, it either stops irritating you (not so problematic anymore), or it does irritate you, in which case you should extract it or have a doctor do so for you.

[@kitcarlson6033]

Skin pores have direction, rub proximal to distal to remove fibers.

[@NathanBuildsRobots]

What does that mean??! I need a compass!!

[@NathanBuildsRobots]

Like, away from the body?

[@NathanBuildsRobots]

That makes a lot of sense in terms of flow optimization

[@NathanBuildsRobots]

But also I don’t think they are opportunistically finding pores, they are small and sharp enough to just poke in wherever

[@fzigunov]

I'd like to know what that means as well... "Rub from the close side to the far side" which side is which?

[@hairypaulmm7wab195]

THANK YOU for confirming my suspicions I have avoided using carbon fiber parts on mountain bike builds for years. Over the past few years growing numbers of parts have been turning up in RC cars, especially after market parts. Most RC car parts appear to be made using various themo set, extruded and cast materials but there are some parts that leave dust and fibers behind when handled especially when abraded, this problem gets worse over time as the parts get worn from use. It would be very interesting to see what You find looking at RC car and scale model parts. I also wonder about safety issues with using 3D printed switch covers and control knobs on switches, potentiometers and rotary encoders used in electronic projects. We are already aware of the dangers of modern plastics and rubber parts gassing off and avoid using polyurethane coatings and finishes. Your findings with 3D filaments prove there are legitimate safety concerns that people need to be made aware of when 2D printing and using 3D printed items.

[@shadesofvioletcat]

Thanks for that title 😂

[@NathanBuildsRobots]

Thank the guy who commented it in my last Short video 🙂‍↔️

[@Ministrator03]

Thanks for your research dude. I handle ESD-Filament and parts printed from it at work. Those of course just contain powder instead of strands most of the time, but your video still made me rethink the entire safety side of the processes.

[@chaosordeal294]

If they're in your hands, they're probably in your lungs, but the real danger of 3D printing is that 97% of prints go straight into the garbage, and then the ocean.

[@zumuvtuber]

I've never used carbon fibre reinforced filaments, but this is great information to know about. We definitely need more transparency when it comes to filament manufacturing and safety 🙏

[@alecubudulecu]

I tested this today, due to your other video... and yes, I saw crystals and splinters in my skin. washing.... didn't remove all but it does remove most. unfortunately... guess I'll have to trash my CF spider man mask.

[@ericlotze7724]

Just coat it in something!, still good to be cautious about these things in the future though.

[@alecubudulecu]

@@ericlotze7724 exactly. A clear coat spray should work

[@Growered]

Skin regenerates and sheds off, fibre can stay in the first layer of skin, but just after good hand wash everything gets out

[@mlgcactus1035]

Except if it get into your dermis layer. Learn to pay attention 😁

[@tankycatcool63]

lolol linkin park refrence

[@matt-lang]

Just use scotch tape as a standard method to check the fibers in the filaments going forward. Other "skin-like" alternatives won't have the combination of oils and texture that will pull the fibers off the filament, but scotch tape is a very well standardized tackiness and can be used as a consistent reference for further evaluation. It's also translucent (like human skin) so it will let you observe the fibers more easily.

[@cexinho]

Did you give a try to paper sheets instead of your finger? Otherwise just get a piece of chicken with skin on x)

[@pmiguelpinto90]

How safe is coating with superglue? Isn't it bad for health?

[@NathanBuildsRobots]

Should be fine once it’s cured. The fumes should be avoided and don’t get out on your skin/eyes

[@RL.1]

We don’t need anymore government regulation, FFS. Give your head a shake.

[@LoneHawk]

Take your uneducated opinions elsewhere

[@NathanBuildsRobots]

Most companies already provide documentation on safety information for their filament. It doesn’t have to be printed, just made available online. They don’t even need to pay for testing, just add a line to a document they already have noting to take care when sanding or making parts intended for food storage or wearables.

[@RL.1]

@@NathanBuildsRobots Fair enough assessment. Thank you.

[@802Garage]

I'm not saying the government should intervene in this case, but people said the same about Asbestos and seatbelts, among countless other examples, like drunk driving.

[@bowieinc]

I imagine a clear epoxy would be best, but what’s your guys opinion on several layers of acrylic clearcoat sprayed on to 3-D printed carbon fiber composite materials. Would that make it safe enough to handle?

[@lukthere2]

But do these carbon parts stay in the skin? Seing as the skin naturally flakes off as newer layers of skin move towards the surface, wouldn't these particles be slowly removed? Especially on your hands, where this process is usually faster than on other parts of the body.

[@williampowell2078]

You're spot on! Maybe some thought should be given to heterogeneous materials in whether the base material 'wets' the bound material during manufacture. I don't feel inclined to use stuff that sheds fibers.

[@jaredb908]

It would be interesting to compare different brands of CF and GF filaments under a microscope to see which are safer than others. After watching this and your previous video I was terrified having just finished a project using PA-CF. I went ahead and got a microscope today and took a look at the Polymaker PA612-CF I have been using and to my surprise I saw little to no fibers sticking out of the filament. Of course, when looking at the broken off end of a piece of the filament I could see fibers sticking out. After seeing how well encapsulated the fibers appeared to be, I rubbed some of the filament on my finger and under the microscope saw that no fiber had come off. With that being said, it appears the biggest concern (unless if you sand a printed part) is the danger of loose fibers dislodging from the filament and becoming airborne via a hot end or part cooling fan. After seeing drastically different results with my particular filament than yours, I even looked at my PEI build plate as well as my extruder gears and surrounding area and still found no evidence of loose fibers which was a HUGE relief. Thank you so much for putting a spotlight on this!

[@dogprowilhelm7630]

Had a 1/4" dia. fiberglass rod embedded in my palm and it grew out after 2 decades. Wear gloves and a respirator at all times when handling raw carbon fiber, or fiberglass. The newer graphene is a nanoparticle producer and synthetic spider web can be nontoxic. Stay safe❤

[@Timedelayedfuse]

Have you considered using PPE when working with hazardous materials?

[@ABW941]

Is this only the case for carbon and glass fiber, or is there also a problem with wood and metal pla?

[@SoraSkyAtic]

I can already hear the title sings in my head.

[@pauljs75]

It's like grabbing a cactus in terms of what can happen. Anyone who has done work with stuff like fiberglass knows protective gloves are needed to handle it. (The very beginning of the video makes the point, although there's plenty provided to support that.) Also you can go to a dermatologist for treatment of wounds with issues from mishandling such materials. Dermabrasion is a bit of a painful treatment, but it will take the fibers out if done properly.

[@shiro5392]

I got a carbon fibre trove wallet about 5 years old now. And I always wondered from the day I purchased it if the carbon fibre was actually an issue as it breaks down. Considering basic things I had read about the material prior. I emailed the company asking and they obviously said it was fine. But do you have any idea? Does it depend on the way the carbon fibre is made? As this part on the wallet definitely does fray and breakdown over time like any material. But is it actually of any concern?

[@KrazyKaiser]

This makes me really happy I've only ever used reglear PLA.

[@MrDarkbluewater]

Got a metal shaving stuck in the skin on my finger in the past. It always looked like my skin was slightly dirty, and when ether I tried washing it off, my skin would itch in that area. At some point, I got sick of it and just cut it out. Turns out, it got over a millimeter deep into my skin over the years.

[@boeubanks7507]

Okay, I worked in a fiberglass factory. Getting the fiberglass shards in your hands was an occupational hazard. However, there really weren't any negative effects from it. Over time, the pieces would work their way out. If they became annoying, you just used some tweezers or tape to pull the fiber piece out. Worst case, it would make a little sore that you may have to open with a sharp blade because the skin formed a cyst around the fiberglass. Not a problem, the cyst is one of the body's natural defense mechanisms for irritants. They can form around any foreign body, ingrown hair, etc. They are only problems if they become irritating, painful, or infected. After I stopped working there, it took about five years for the fiberglass pieces to totally get out of my hands. It is a slow process. So, how dangerous is the material itself? Fiberglass is inert because it is a refractory material. The processes used to make that glass are so extreme that your body is not going to break it down. It is also not going to just decay in the body because the refractory process generates an extremely stable amorphous glass matrix. However, this is only for the glass fiber itself. All glass fiber is coated with a binder to cool the filaments and bind them together when collected, wound, and twisted. Most binders are some form of industrial starch. So that isn't harmful. However, there are exotic formulations that utilize some harmful chemicals. These are typically for specialized applications, though. Given the ubiquity and low cost of glass reinforced filament, it is likely a starch based binder that is compatible with the polymer matrix of the filament. As for carbon fiber, the jury is still out a bit. Carbon fiber has only been around at a large scale for a couple of decades, at this point. However, there is no indication that it is a toxic or particularly harmful substance. So, I would generally put in a similar vein as fiberglass, but with more of a caveat. That said, both of these can be irritants, so handling rough parts with gloves, even latex or nitrile gloves, and taking proper ventilation precautions when sanding are not bad ideas. I don't see the need for a respirator, but good air flow away from you and/or a dust mask would be good ideas. Also, some safety glasses to protect your eyes. Basically, the same precautions you would use if you were working with wood.