Composite Core Construction

[@realcygnus]

so.......I've found some cool channels over the years. & this is one of the coolest. Perhaps google upgraded its recommendation algorithms or I just got lucky. It was a great find though. Interesting & useful yet somewhat diverse content. I already got more stuff than I have time to watch, which is why I hardly ever need to seek out new channels. & damn this dude is smart. & man do I wish I could afford all that nifty apparatus myself. I Need a neighbor like this.....I'm considering relocation lol.

[@M1keLucien]

I just had the same experience :)

[@WrinkleRelease]

Agreed. I'm really impressed at his knowledge base.

[@timothyandrewnielsen]

Let's all be his neighbor. We'll start a cult of engineers and end up migrating to Mars in 20 years.

[@lordslavik]

what are your other favorites?

[@carrotbailey]

Same homie. I’d watch this dude talk about anything. One day my shop will be like his i hope

[@djorfuusk]

Seriously.... thank you for all of your videos.. I’ve watched a fair amount of your posts but never commented, but dammit it’s time.. The range of subjects and processes that you tackle are a GOLDMINE to makers, breakers, thinkers, and tinkerers, and you should know that your time and effort is most definitely appreciated. You explain each process in such a way that it almost seems like you know what I’m going to ask before I do. All in all, every one of your videos have taught me something invaluable or made me think about a process/project in a new way. To be completely honest, half of the time I end up at one of your videos by accident through auto play or the random suggested video scroll panel; now being a perfect example. I started out researching piezoelectric synthetics and their frequencies aaaaand now I’m here lol.. That being said, Im pretty happy that I landed on this particular video though, as Ive been thinking hard about a homemade boat project and had all but written off the idea of using wood (of any type) for the the frame/stringers. After seeing this video though, balsa frames aren’t looking too shabby (when compared to the cost/weight of composite paneling)... Thank you very much for walking through materials comparison and epoxy/filler process! Anyway, sorry for the novel.. I just wanted to thank you for taking the time to make these videos and (more importantly) for going into such fine detail and explaining the science, nuances, and reasoning behind each project. It is very much appreciated. Best, Thomas

[@TechIngredients]

Thanks, that's very kind and it's reassuring to hear that after spending a considerable amount of time on these projects. Oh, we're currently building a hydrofoil catamaran.

[@brian2k1]

this is the best channel since I found AvE many years ago. and thanks to this excellent video I have a newly found love and appreciation for Balsa wood! thank you!

[@ollieb9875]

Brian Boatright dead tree carcasses! 😀😀

[@nicewhenearnedrudemostlyel489]

Many years ago? Like, six tops?

[@Ian-iu2tl]

Absolutely love your work. I am employed as a machinist/technician at Carleton University, Canada's premier university for mechanical engineering. I am involved in a large variety of projects from aerospace, mechatronics to biomed and beyond. It just never stops and that's great!! :). Your lab is fantastic...cozy and very cottage like. Seems like a good place to sleep. Ha Ha! I am eager to watch ALL of your stuff and to see future vids as well. I agree with some of the other comments regarding the music. Just doesn't fit the mood. Wishing you the best. With respect. Ian

[@siggyincr7447]

Great way to avoid the balsa from sucking up a bunch of epoxy with the micro spheres. I assumed you were going to use a higher viscosity epoxy that didn't wick, but this is a far better solution. Really interesting channel, I just discovered it today and am looking forward to going through your videos.

[@deyc3]

I'm wondering if whipping air into it would achieve the same result?

[@heinzhaupthaar5590]

I usually just use one resin, a very low viscosity infusion resin, and no additives. To avoid excessive wicking I just brush on a Layer, wait until its geltime is reached and proceed. With extremely spongy and sucky materials I do it twice if needed. Tested it and in many cases it's lighter and stronger as well compared to other solutions, the bonding is way better. Test pieces didn't delaminate/buckle or whatever, like they did with about any other method, the core material simply ripped apart. And not just end grain Balsa, even with Baltic Birch, Acorn etc., Airex or XPS - the poor folks Airex - of course just crumbles no matter which way. I believe it makes the core material an integral part of the composite structure, with a wet-in-wet layup on top of a "wood epoxy composite" instead of incorporating a failure point on purpose, and with the gradually decreasing epoxy content in the wood it seems to have an excellent load distribution. It's rather hard to get the process perfectly repeatable though, a spray gun and metered amounts would be the least I guess. But as amateur or for one offs - who cares? Try it! It's simple and you don't need any unnecessary additives.

[@atomatopia1]

Give a man sealed balsa wood and he’ll make a composite core structure for a day. Teach a man how to seal balsa wood and he’ll make composite core structures for a lifetime.

[@lorriecarrel9962]

Your children are so very fortunate to have you as their father,genetically and as a role model

[@loneranger1951]

Fantastic videos. Please consider sharing your material sources. I think you could do well with affiliate sales from your website; cross listed and/or indexed by technology, videos and kits. Sourcing is half the battle for breaking into new technologies. Great shop/studio!

[@sumguysr]

Boy it'd be great if you made an update video on all your old projects. I want to hear about the APU and the armor and concrete!

[@jbird448]

Your channel is so wonderful. So educational. I am excited to try new things. Thank you.

[@themountainraven]

Thank you for the inspiration once again for self study into material sciences. Your videos are spot on, and you are a phenomenal teacher, not to mention i appreciate you trying to be precise with terminology. That really helps my searches.

[@TechIngredients]

I'm glad you're here. Thanks!

[@zivfriedman2312]

Every single time that I see one of your videos, I know I'll learn something new, and every single time I am amazed at how much information and details about a very specific subject you can deliver! Simply amazing Thanks

[@alexanderSydneyOz]

Gosh! I've recently watched some of your more recent videos about resins, but only just realised the breadth of your expertise across a range of technologies. This is all as impressive as it is meticulously explained.

[@TechIngredients]

Thank you!

[@kontoname]

Awesome video and the music made it much more cheerful, alive and vivid.

[@user-pn6mv4wy7w]

Your channel is so beyond detailed. Thank you so much for the time you take to share your vast knowledge.

[@jeffbrinkman684]

I always wondered why boat decks had the little cubes of balsa. Now I know! I am so glad your channel got recommended by the algorithm!

[@TechIngredients]

Welcome!

[@lorriecarrel9962]

You have a incredible ability to teach with efficiency in doing so that astounds me,I genuinely hope you make good from doing these videos cause you deserve every bit

[@WRARRior]

You are my science guru. It seems as though every project I stumble into, you tie in as source material in some form or another. Thank you, and please, keep it up!

[@TechIngredients]

Sure.

[@first-thoughtgiver-of-will2456]

Thank you for the work you do on these videos. They have inspired my to research areas of science I wouldn't have otherwise. KZbinrs like you reinvigorate my passion for science.

[@TechIngredients]

Thanks!

[@edgmp]

I've been a fan of composites for decades (used to sneak off to Jr. High school library to read up on what Bert Ratan was up to ) Thanks, informative.

[@Casey_Schmidt]

This is so cool. Why have I never seen this channel before? Great work guys and I love seeing the material experimentation for all of these projects. It's awesome that you guys do solid research for your projects rather than just throwing a bunch of stuff together hoping that it works out. Keep up the great videos!

[@oldhobo5610]

Very good video and I have subscribed. Epoxy resin to hardener ratios are commonly specified by volume. Using a scale is more accurate (especially with smaller batches), less wasteful and less messy. Some epoxy manufactures give alternate ratios by weight, others don't but you can calculate it if you can get the densities from the product data sheets. For the products I use 2:1 by volume translates to 100:46 by weight, and 3:1 volume is 100:32 by weight.

[@donaldasayers]

Thanks, I did not know that you could buy balsa as end grain panels, useful.

[@EggBastion]

Quite!

[@CaseyHancocki3luefire]

I really wish there wasn't music throughout the video. your more recent videos are so much better. I am very thankful for your channel. Please keep making videos.

[@TechIngredients]

Thanks!

[@corycrow5147]

Very cool, worked the aerospace industry for 30 years and seeing balsa core brings back memories, I also play with pulsejets so I’m looking forward to seeing the ideas for making yours more efficient. I’m burning 500cc/min to produce 12-18 lbs of trust. I’m high for the amount of thrust but don’t burn valves at any rate.

[@M1NDR34D3R]

I really appreciate the effort and care that you put into your videos. In this specific video, the background audio is really diverting my attention though. It made me stressed and unfocused. You have made some great improvements in the video production of your more recent videos. Very glad to see these changes. :) On the subject of how you explain and go about practical projects, I'm very impressed. Way to go! Excited for all upcoming content. Thank you!

[@TechIngredients]

Thanks!

[@youmakeitreal]

Thanks for putting this info up. Happy to have come across your video. I have been debating core materials for the last 6 months to use on a fire wall repair on my Lotus Europa. I had looked into Coosa board and Nida Core manufactured materials, but after your demonstration of the properties of end grain balsa I think I have a winner. I also appreciate the extra info on proper preparation with coating epoxy/micro balloons on the core to promote adhesion and reduce wicking.

[@qwertyqwerty9587]

That opening statement awnsered every question i have 😂 thank you

[@Jefferson-ly5qe]

I've got some serious shed envy watching this :)

[@onenewworldmonkey]

I realize this is an old video and you'll not read this but I must say that your explanation of the forces at the beginning was excellent. You said the top is under tension and bottom under compression, which is how the limbs of bows work. This year marks my 42nd archery season and I collect bows. It is interesting how different cultures solve these parameters.

[@TechIngredients]

The universe is what it is, it's up to us to work with it. That's engineering no matter what the application.

[@lorriecarrel9962]

I clicked on this video and seen that it had a thumbs down and I never did such a thing,maybe a glitch? I wonder..I changed it to a thumbs up cause all your videos deserves a thumbs up for sure

[@TechIngredients]

Thanks for checking! Like other channels we have also had viewers complain that they were involuntarily unsubscribed. KZbin has been redirecting viewers away from original content creators and toward corporate sites beginning around 2016. As you say, this may be just a glitch...

[@hallkbrdz]

Thank you so much for this video. I've been looking for something that will provide a core for S2 fiberglass for building battery boxes for electric sprint karting that are both light and very strong (especially impact) while also resisting heat. I had looked at a lot of foams and hexagon materials that are as you say, very pricey or not that rigid. This seems like the best of both worlds.

[@therealgaragegirls]

Thank you for all the incredible information. Learning a lot today.

[@TechIngredients]

Great, more incoming!

[@John7891]

The very successful WW2 fighter bomber, the Mosquito, used a lot of balsa in its construction. Very good material, probably under rated in todays high tech world. Excellent video; I learnt a lot.

[@TechIngredients]

Thanks!

[@danielleriley2796]

In aircraft a similar product is GLARE glass laminate aluminium reinforced extrusion. Strong as and light as. Another one is a hexagonal aluminium sheet that’s about 10mm thick the hexagons are on the vertical axis and the aluminium is goddessly thin as in thin enough to easily slice your finger. And that honeycomb sheet has a GLARE top bottom and sides and is rigid in all dimensions with fantastic sheer strength. The GLARE outer layer is only about 1.2mm thick and has 2 aluminium layers between 3 glass layers. I’m sure there are more sizes but this is the one used at my work to make chart tables in the rear of our surveillance aircraft. They weigh less than the scales that measure them and can be stood on by an adult male. Well by you but not the average USA male these days. The sheet structure comes in very large panels and you cut it to shape and add the edging. I haven’t done it myself but I have seen a damaged table top that had a corner gouged out be repaired and the engineer said that once the crushed edge was removed that you just re edge it like it was originally and it just as strong as before. And I watched him do that. I’m the captain so I’m responsible and it was interesting as all get out. And yes I bled all over the floor and my flight suit playing with the cutoff. The air gap between the layers is sound muffling and the laminated faces reduce sharp sounds.

[@robertchilders8698]

I learn something new every day! Thanks so much!

[@roberthenderson3406]

Brilliant, watched a few now but please loose any music in the background. You don't need it. Its wonderfully instructive. Thanks.

[@Buzzhumma]

Certainly a wealth of knowledge . Much appreciated 👍

[@randysonnicksen9475]

Great video and explanation of how (sandwich) fillers work, and tradeoffs. Love the info on balsa. I have not used it yet, but this video has convinced me to get some to experiment with. I am working on a project which will require every lightweight construction technique I can come up with.

[@JerryVitale]

Great channel!! I started watching you laser videos but always enjoy your in depth explanations. Can't wait for the RF stuff ;-)

[@nicholasvangreat260]

This is one of the best videos I've ever seen in my life - thank you, Sir, for taking time to educate us!

[@Miata822]

I've done this with boat repair. Used fiberglass rather than carbon fiber. West System sells the epoxy and a wide variety of fillers with various properties. If you look up boat repair you can get many good tips (and some bad ones).

[@TechIngredients]

You're right! We're building a hydrofoil catamaran at this time. Stay tuned.

[@amendment2concepts299]

Always nice to learn how others tackle a challenge.. good content ! Thanks for sharing !!!

[@jm-ux5dk]

It's good to see you making a video in my field of work, I would tend towards using a vacuum to pre impregnate the core when using epoxy, especially for balsa wood its ability to wick is astounding or even using a thickened isothalic resin which gives less working time but uses less material.

[@TechIngredients]

I have found pre sealing with the thickend epoxy works best if you can't get the surface sealed end grain balsa directly from Baltek.

[@MrAndycm]

Boy did I get lucky finding this channel! I love it and have subscribed.

[@johnbutterworth608]

Thanks for demonstrating. I grew up with an inventor and laminates were the majority of the process.

[@68HC060]

Again a great video. I had no problems with the background music, but reading other comments, I think you could set the music volume to be slightly above "barely hearable". My main motivation for this comment, though, is that I think one could be a little more 'lazy' and give the carbon fiber sheet a coat of epoxy, then wait until it started hardening but still "tacky", then add the Balsa; I believe the epoxy would not get too deeply into the Balsa then. I also thought about the foam... popsicle+foam+popsicle+foam+popsicle ... this would only give you stiffness in one direction, though - however if you have no Balsa but a lot of foam and thin strips of wood, it could be an alternative to get lightweight stiffness. One could also use a bunch of thin strips to make a "torsion-box". -Or if you have a bunch of corrugated cardboard (it can be acquired as "paper-ish" rolls), you could make sheets / rolls and slice them into boards using a cheap (large) handsaw - thinned PVA glue is usually fine for gluing cardboard sheets (eg. from box sides).

[@meandmybuddymcgee]

One of the most educational channels on YT. Priceless for the time spent. I wonder if instead of filling the balsa with "nothing" (the micro spheres and the additional epoxy ) one would not get the same result by placing the mixed epoxy on the carbon fiber and laying flat the balsa on top letting them cure this way and then repeating the process for the other side. Some epoxy might capillary creep into balsa upwards but I doubt it to be too much. Just a thought... Anyway, I have learned a lot from you, so... thank you and keep up the fun education for the rest of us.

[@TechIngredients]

Thanks! The capillary action of the balsa channels will still draw the epoxy away from the carbon. The force of gravity is small by comparison.

[@meandmybuddymcgee]

@@TechIngredients Thank you! Another afterthought I had (after initial posting) was to lightly sandblast (or sandpaper) the carbon fiber creating some retention (wetting) A lot of fun anyway, thanks again.

[@friendsonearth]

Nice, like to see more on videos on composite core construction, there are not many videos on what you did, Thanks again

[@TechIngredients]

Thanks.

[@hiddenchambers2922]

Thank you for sharing! I love the music too!

[@haydo8373]

Wow, so much useful information in one video 👌

[@Heywood-----Jablomeh]

Absolutely superb explanation of the whys and how’s for us amateurs!! Thankyou

[@nakul3424]

Thanks a lot for this very informative video, appreciate the efforts

[@Electronics61]

Great video. Love all your great videos. Hopefully if possible please do video on FLASH GRAPHENE or something similar. I am planning to build the required capacitor bank on the lines of Rice University experiment.

[@solopianoamico...6719]

The new background music is very pleasing... I was used to listen to my own music during your videos, but that's ok! One thing is that it's always the same music now, and watching the video multiple times, as I like to do, isn't as pleasing at the last time, as much as I find the music is of very good taste and upfeeling... Bit of a tradeoff here. I still prefeer to listen to my playlists to match my mood or time of the day. Hope you find this usefull!

[@sonnymoon6465]

Hi and Thank you ! Super interesting. Like taking physics and chemistry which teachers always wanted to flunk me in though I liked them so much ! Yayyyyyy KZbin and Tech Ingredients !!!!!!!!

[@Alexander_Sannikov]

Very interesting stuff, I like it. Wish you've shown strength of result composite though.

[@zrebbesh]

My problem with balsa as a composite filler is largely the same as my problem with most composite filler: water intrusion. After some number of years, some point on a boat hull is going to develop a hole the size of a pin that allows water to contact the filler material. Thermal expansion/contraction will force water in. Most composite filler materials quickly start turning into structurally useless mush. And the mush spreads. Below the waterline there's no composite filler that really lasts. If you want a boat to last more than a few seasons you have to get an old boat from when nobody even tried to do fancy layered composites and they were made in solid (and yes, heavy) fiberglass all the way through.

[@robertchilders8698]

A poor layup leaves behind microscopy air bubbles! Usually from working the fiberglass to fast. Yes, it can take on water over time and can cause severe damage!

[@kkeller]

Putting that epoxy on the balsa looked like spreading Nutella on a warm piece of toast! I must be hungrier than I realized. :-)

[@lorriecarrel9962]

For sure my favorite channel

[@roberthill4239]

Thanks for all you do. Very educational.

[@PodeCoet]

Love your work mate! If I may offer one small piece of criticism, the music is really unnecessary (and honestly a little distracting)

[@kosh604]

Agreed, the content presented on this channel does not profit from background music. Better to leave that to the entertainment channels.

[@amendment2concepts299]

I agree but I also find the content entertaining , I will say trying to imagine technical content with music going for me is tough but I have a coworker that is the total opposite..

Make your own damn videos and stop whining.

[@nzpork1]

I find it easier to concentrate on what he is saying with the music.

[@odudex]

Audio quality is great and this low volume music makes the class more pleasing, keep it!

[@stevesplace7230]

Pallets for military and commercial aircraft utilize two inch cross grain balsa and .040" aluminum. These are 8x8 foot pieces. Very little bending and very light. Only downside is corrosion. I'm thinking you built a composite aircraft (VariEze) or some other Rutan design. Nice work.

[@outgoingcare]

2x6" x 10' chunk of foam was covered in fiberglass resin and cloth. It was supported by 6" blocks on both ends. I jumped onto it figuring it would break. No. it was incredibly stiff. The builder ran threads of wetted fg rope, bonding the top to the bottom. Details unknown, there must be an application.

[@Lao-G]

I feel like this would be a very good application of stabilizing resin, apply it to balsa prior to carbon fiber application. Downsize is the cost and added weight, but you may see some significant increases in rigidity and hardness.

[@oddjobbobb]

I read down quite a ways looking to see if my question was already asked, but I didn’t see it. I am curious why you don’t immediately lay at least a lightweight piece of glass in the thickened resin a soon as you have the balsa coated. I NEVER fail to learn from your videos.

[@duane8620]

Best demo on jet/fan propulsion I've seen. Great work on creating that hybrid too, I can see you machined most of those items... Impressive.

[@Macatho]

Thought it was called amorphous. Thixotropic, never heard of - guess you learn something new every day :) Thanks :)

[@TechIngredients]

Sure!

[@ThePaintingpeter]

I recently discovered your channel and it's fantastic. You are very good at delivering technical information in a very accessible way. With this composite video, it didn't address an issue that came up after I watched the video noted below. I'm trying to understand the interplay of differing materials used in composites used in surfskis The typical configuration is some combination of Kevlar, carbon fiber and nomex honeycomb. The properties of those materials seem to be at odds with each other. They also don't seem to address the common failure point just fore and aft of the cockpit when the surfski breaks through a wave and crashes down on the other side. There is a strong compression on the top and a strong tension force on the bottom. This would presumably cause Kevlar to fail at the compression side. Choosing a single material that is better at handling all forces compared to the darlings of Kevlar and Carbon would seem appropriate. That being S-glass. Can you point me to any sources I can investigate to get clarification? Thank you.

[@ThePaintingpeter]

The missing link kzbin.info/www/bejne/gXm7h5lmiMZ9pqM

[@TechIngredients]

S glass is actually stronger than carbon and tougher than Kevlar. The downside is that it's significantly heavier. It works well in both compression and tension.

[@ThePaintingpeter]

@@TechIngredients so do you prefer a single fabric on the outside layers or is a combination of materials, at locations specific to their stresses with other beneficial properties like being lighter

[@TechIngredients]

For anything short of a very specialized competition design (expensive), keep it simple.

[@regdor8187]

Balsa was used as core in some early glass sailplanes, however microbiology eventually destroyed them as No seal is perfect especially when under stress, however if you are building something shortly disposable, go for it.....

[@jmoser1030]

I've found that when mixing epoxy if I mix it until well mixed, then put the contents into a new clean container and mix it some more I get a MUCH more consistent mixture.

[@yehudagoldberg6400]

Balsa is not cheaper than foam in the northeast US. For example, 1" 4x8 XPS is about $20. By comparison, the same square footage of balsa 3/8" thick is about $120, and you probably have to pay shipping as well since it is not usually available locally.

[@nicolashuffman4312]

You can use fumed silica instead of phenolic microballoons. It only takes a few percent to dramatically increase viscosity. Just be sure to use a respirator, as silica is not good for the lungs. This material will have almost no color, so it may be more aesthetically pleasing under fiberglass.

[@TechIngredients]

True

[@Moist_yet_Crispy]

Another fantastic video! Loving this channel more and more. :)

[@rogermccaslin6750]

I know I'm a little late to the party but I thought I'd throw this in as food for thought. A better thix agent is anhydrous fumed silica. It is harder to sand but the resultant mix is stronger. Also, there is a wide variety of foam cores (PVC, SAN, PET, etc.) available that can achieve good structural values and save weight over end grain balsa. It very much depends on the application as to what might be the best combination of materials.

[@TechIngredients]

Actually, although you are right about the thix property of fumed silica, for this application the much lighter phenolic spheres bulk up the denser epoxy and save weight. This is better because the interface strength is core limited. Those other cores have benefits, but other than Nomex honeycomb, none have the same compression to weight ratio of end grain balsa.

[@cbbbbbbbbbbbb]

Just revisiting this video after rewatching the "Super Strong Epoxy with Diamonds and More!" video from 2020. Out of those materials presented, would you stick with the phenolic microspheres for this application? The thought is to build a lightweight plane wing so with the UV exposure, maybe one of the powders from that video (graphite, aluminum, dendridic copper) would also be a good additive. In this instance, it would of course only make sense using balsa wood vs a foam core since the foam can be used with plain epoxy.

[@macwol]

Absolutely fantastic content! Also watched the 'Easy Tricks Using Fiberglass Strengthening!' and I could't stop. So much knowledge, thank you for sharing it! I came across your channel looking for a solution. I'm building a sit/stand desk with quite a bit of weight of equipment attached to it. I decided to reinforce it with two steel plates where I would place two heavy-duty monitor arms. The problem is that the plates added quite a bit of weight, so much so that there is much more stress on the rear legs than the front ones (it's a 4-legged frame, with 4 separate motors). This contributes to a significant wobble at the start and finish of the motors' operation. Would you be able to recommend some kind of material I could use instead of the steel plates? It doesn't have to be the lightest possible (like balsa wood) but the steel in an overkill in this case.

[@maggie4834]

Another great video 👍. If you’d like the XPS to take a greater point load you can always try Owens Corning FOAMULAR 1000 😊

[@johnkennett2596]

You are a Pro at simplifying then Communicating the useful advances in science of physics, chemistry, space age construction to those of us DIY dim bulbs who want to home build an advanced technology project. Such as ultra lite airplane combo car top aerodynamic, solar powered ground effect boat, capable of safe, affordable, fast, and reliable flights one meter altitude over water.

[@Len02013]

Thanks interesting video. I’ve never even thought of using cross gain balsa, I like it

[@oddjobbobb]

Len d I don’t think this is cross-grain balsa. That sounds like plywood. This is end-grain balsa. It is put together in small squares where the glued edges are the long grain, not the end grain. I think the manufacturers of sheets of end-grain balsa do this because one of the drawback is to this material is if the costing fails, in an underwater setting like the hull of a boat, or even on the deck, the balsa will wick water and saturate very quickly, and it rots very quickly. Making the sheet from small squares reduces how far and how quickly the water will migrate.

[@stace5676]

@@oddjobbobb The reason for using end grain balsa was explained early in the video with the bunch of straws, it has higher strength against bending when laminated.

[@garyl6031]

Another Awesome video! Have you looked into honeycomb cardboard? I used it a couple times in the past with aluminum sheeting and it worked great. Sealing edges was really the hardest part of the job.

[@aussiepete1]

Great video. Could you add reference as to where to get the materials including carbon fiber? This could help in getting support for these video from suppliers.

[@robertf1720]

Ebay, Amazon, and your local search engine. :-)

[@iantherealg]

I love your videos, but the best benefits of fiber mat composites like CF/Kevlar/Fiberglass are that they can be extremely flexible while also being extremely high in tensile strength. Their major downside, as you pointed out is the lack of compressive strength. Using any more epoxy than necessary will lead to a brittle result that will have fewer of the benefits as well. This is why prepreg + autoclave type composites are so sought after: they're just so amazingly flexible because they used the absolute minimum epoxy, to the point people have to work them into molds for hours to get all of the layers to match and sit flat on each other before the curing process. So to me, I see that layer of plugging epoxy as detrimental to the end result. If I had to do a wet layup and use balsa, then I would experiment with letting the epoxy sit until the very end of the pot time so that it becomes almost tacky, then heat it up as a catalyst to the chemical reaction, which will also allow for about a minute or so of time where the epoxy becomes runny again. During that minute, I would try and lay down the fiber mat, wet it, and get the excess epoxy off the mat asap. As you pointed out, it would delaminate if the wood soaks up epoxy without replacing that epoxy, so I would try and time my second pot to be about half done setting, so the second layer of fiber could be laid down quickly, sucking areas of excess epoxy into itself and also allowing the epoxy poured onto the second layer to flow into the voids created by the balsa sucking the epoxy in. You could also just ignore the weight and costs and instead saturate the balsa ahead of time, which would give the resulting composite some interesting characteristics if both mats simultaneously took a compression blow (from the side) for example on a hydrofoil that could be susceptible to hitting rocks and not just flexing under the weight of the lift. Perhaps even using a kevlar carbon fiber hybrid. I also think there could be some merit to doing the wet layup and then tossing the wet layup into a vacuum bag to suck the air out of the wood fibers/cellulose/hemicellulose and thus prevent the epoxy from flowing into said wood fibers. Perhaps this would result in an exceptionally light weight end result with the closest adhesion of carbon fiber mat and balsa possible, so that a compressive blow is transferred almost directly to the wood grain and not through the carbon fiber, layer of extra epoxy (which would shatter), and then finally the wood grain.

[@TechIngredients]

Thanks. Having worked extensively with these cores and fiber reinforcements I can tell you that timing the application of the epoxy to coincide with the bitter end of its pot life will be very frustrating. Even if you work very fast and without any application time variability, the epoxy that remains in the pot will spiral to extremely high temps in a few seconds (as little as single digit seconds), potentially burning your hand, melting the pot and even combusting. If you attempt to spread it around after pouring the whole batch on the part, you run the risk of it gelling before it is distributed and running the composite.Sealing an open pore core first and then laminating to this works very well and produces strong and reliable bonds.Saturating the balsa undermines its unique structural and weight advantages. It would end up nearly as heavy as a solid epoxy core and its isotropic stiffness/strength will add unnecessary weight.

[@iantherealg]

@@TechIngredients it's true that the reaction is exothermic. How hot it gets will depend on a few factors: how much epoxy and it's surface area in the pot, the epoxy mixture, how far along the reaction is, and how much heat is being added. It was meant as an experiment for the small piece like the one being worked on. Do you think mixing in glass microspheres rather than plastic would work equally as well to seal the wood?

[@TechIngredients]

Glass micro spheres will work just as well if not better as the epoxy bonds to them better. Actually, even the small part I demonstrated would be difficult to coat with epoxy that is about to "go off" as people who work with it call this run away heating. It is so rapid that when you dispose of any residual still in a mixing cup, it is best to spill it around the inside of a trash bin to prevent it from beginning to smoke. Been there, done that!

[@JohnCHansen01]

This topic was well presented. May I ask a few questions. NOTE, I ask these questions because I have not yet found any other site that discusses the weight (or specific density) of the end grain balsa that is sealed with any material and also provides the weight of the reference balsa that is unsealed. ~~ Have you or anyone developed an optimized sealer for balsa where the control (reduction) of weight is the primary objective? ~~ Can the phenolic spheres be measured by volume in order to simplify the formulation? ~~ When purchasing the end grain balsa, what density did you purchase and did you weight the balsa prior to your demonstration? ~~ What was the weight of the resin/phenolic mixture that you prepared and what was the remaining weight after you applied it to your sample? ~~ With a scale that can weigh materials to 0.01 grams, could the formulations be developed based on weight? ~~ How much weight of epoxy in the carbon fiber sandwich would be saved by sealing the end grain balsa? ~~ Are there any published sources for this information related material weight?

[@TechIngredients]

Those are a fair number of questions. We used the most common balsa density of 6.5 lb/cubic foot. The phenolic microspheres are the lightest available filler for thickening the epoxy. The approximate density of the thickened epoxy is 70% of the pure epoxy. The quantity used is variable and depends significantly on your application technique. Do not attempt to apply the cloth whether carbon or glass to unsealed balsa because the balsa will wick away the epoxy from the interface and prevent a good bond.

[@mytech6779]

That's a common problem with less costly balances. The hardware is just barely precise enough for the displayed precision, which in a raw readout would result in the least significant digit being unstable, so they use a sort of averaging to stabilize the display, which can lead to slow response and even inaccuracy during very slow mass additions as the averaging can essentially self-tare faster than you are adding mass. Lab grade balances use hardware with much more internal precision than the externally displayed digits so they don't need any averaging to get a stable output and have no self-tare issues during very slow loading. I still buy the modest price units but I do so knowing that user technique matters to a some extent. And my microwave oven can effect them up to about 6 feet away. Computers have a similar issue when adding very tiny floating point values to very large values, If you have 6billion and want to add 1 to it another million times you must sum all of the 1s first then add that sum to the 6billion; if you just add 1 straight to 6billion the least significant digits overflow the fixed number of bits in the computer hardware [eg 32 or 64] and the result will get truncated so the recorded output is still only 6 billion even after an infinite number of additions. (As I recall the standard significant digits for a 32bit float is 23bits, plus one for positive negative and the remainder being used to specify magnitude[decimal position]. This is approximately 6 decimal digits of reliable accuracy. As long as the programmer knows of the issue they can avoid it, if needed, by specifying longer floats or software workarounds but these are slower and use more memory.)

[@nikoladd]

Awesome stuff! Love your videos.

[@slojogojo2766]

A way to bond core and have a thin layer of adhesive is to use a very fine nylon mesh net to keep a uniform layer of adhesive between skin and core. This is how we do it in the aviation industry.

[@rocketsurgeon4876]

So if I understand correctly, with a balsa core you would do what he showed, let it cure, sand it some and get it dust free then apply the mesh then carbon on top? Is there a trade name for that mesh so I can find some myself?

[@TechIngredients]

I would avoid both the technique I demonstrated and Ruttigorn suggested if very high performance is desired. The manufacturer of these balsa panels supplies a sealed surface version that is more expensive, but lighter and more effective. It saves time as well.

[@anyalpine]

Cork would also be interesting to try

[@joohop]

Thank you buddy , You have helped me

[@jothain]

Very interesting stuff. As you have very nice shop, access to materials and knowledge. I would be very curious how you would make most cost effective and stiff DIY CNC mill frame. Obviously cast iron solutions are out of the question for hobbyists. I've been looking into possibility of creating mold and doing it by diy stressed concrete, but I don't have that much knowledge and shrinkage might be big issue as also possible cracks if not done properly. Other option would be something composite like. Resin with rock/steel could be maybe option. However I'm personally not confident which would make most stiff and vibration absorbing and moderate weight having solution. I've played with thought that maybe something like resin, gravel/steel and possibly fiberglass combination. Biggest problem I think with any of those solutions would be how to have base withstand desired dimensions accurately as possible as obviously rails would be needed to fixed into this base securely and dimensions for these need to be very accurate and remain like that under stress and usage. I have 3D-printer and it would be easy to even fairly complex shapes for mold. Would just need to figure out some good material combination and internal structure shape.

[@TechIngredients]

I would avoid the composite approch. Even the concrete will shrink and it will be very difficult maintaining alignment with such large and heavy components. An amateur can't fabricate prestressed concrete in complex shapes. Also, time is money. Although there are companies that sell composite and granite CNC frames, like Aerotech, these are really expensive. I'd weld up a frame from heavy, but simple steel components. Steel welds easily, is relatively inexpensive and is thermally stable.

[@jothain]

@@TechIngredients Yeah, you're right. Welding and accessing various steel plates/profiles and even getting them plasma cut isn't problem for me and I can get them very reasonably priced as I can do everything except post-processing cam files and repaired basically free one cutting machine and having that "I'll come some day to get favor back" deal. It's just that space needs are quite crucial for me and knowing metal working (mechanic/welder profession) and it's just that basic steel isn't good for vibrations which are going to be problematic, that's been the reason considering composite base. Buying ready frame is absolutely out of the question as even shipping here would cost very much. Though I suppose I'll lean into making from simpler components as I even have very good access to them as mentioned. Even occurred to me just now that I think I could even get laser cut profiles with decent price, which would make assembly very easy. Time is money aspect is well said which I've kinda forgotten here. Going composite would have to take many, many samples to even get good enough "base" for working. Off to the cad computer it is, thanks for answering :)

[@TechIngredients]

Regarding vibrations, take a look at our "World's Second Best Speakers" video. Build the structure stiff with heavy steel then use constrained layer damping to deal with vibrations.

[@jothain]

@@TechIngredients I just quickly watched that video. Yes, that would very likely be the easiest solution, plus it would be very easy to implement even after completion of assembly, if taken even remotely into consideration when doing the design. Huge thanks, I'll 100% sure keep this in mind. I've done few speakers in past and haven't thought about that possibility of dampening. That's essentially the same which can/will happen in milling machine too.

[@robertgarms8106]

I fly R/C gliders which must be strong and light. We (glider flyers) build our wings using exactly this method. Gliders experience multiple g loads on launch and pulling out of dives as well as in turbulent air.

[@thetruedjlivewire]

reminds me of rc cars and model air planes, though they don't really use nickel cadmium batteries much that i know of anymore.

[@rogercrier]

I was taught that the fillers like micro balloons and fine glass powder bulk the resin up and give it varying densities and properties, but are only causing thickening as a by product so to speak. We used a silica powder to guarantee the thixotropic element, then the fillers to achieve the desired mechanical characteristics. Our microbaloons were white, and we had a brown filler that was even lighter made from some fish based product, but the industrial name escapes me. If you squeezed it in your hand it formed a solid like a snowball, but feather light, so useless for throwing! There is stuff called peel ply, that can be put on the wet surfaces so that they are kept ready for further laminating at a later date. You just peel it off to reveal a matte surface ready for resin.

[@MrEazyE357]

Just a suggestion, when you know something is gonna be loud, hold it just a little farther from the mic. Even small distances can make a big difference.

[@JorgeMarioManuelOrtega]

no background music. ever. thanks. excelent videos. 3d print that stuff.

[@bhughes3663]

Thixotropic might be my new favorite word. Thank you for that. What might it's antonym be? Because I HATE it when people say "liquidy." I tend to use "aqueous" instead, but thixotropy seems more about the viscosity changes over time. This has been bugging me for far too long. Love your channel!

[@TechIngredients]

Thanks! Runny, plastic, self leveling...

[@EggBastion]

Google > Thixotropic + Antonym = Rheopectic. The opposite of viscosity though? Fluidity.

[@oddjobbobb]

470K thank you for that!

[@adambournes8356]

Great channel ! Super content. I was wondering what needs to be done to ensure the filled epoxy layer on the balsa adheres well to the carbon fiber layer? Sandpaper? flame ? plasma? THX.

[@TechIngredients]

Sandpaper works, but take a look at our later video on epoxy "Cheap and Strong" there is an easier, cleaner and stronger method.

[@dennisshen4388]

Agreed with respect to music, your presentation is adaquate, better than crappy music.

[@Linktw0]

This is the best channel ever! A lot of these topics are things i'm quite familiar with so I always start watching this thinking i won't new anything new in terms of science but i might get inspired to try some new technique or whatever.. So far, i've never been right about the science part lol. The diversity of in-depth information keeps surprising me every time and its so impressive that your knowledge stretches out over such a wide range of expertise. Thanks again teach! keep em coming! PS. Could you tell me if the tubular orientation in your piece of balsa wood is manufactured like that specifically for use as a hybrid composite core, or is it a typical characteristic of sheets of balsa in general (im referring to the panels i can buy at my local hobby shop, would they most likey be suitable for this application?) cheers

[@TechIngredients]

Thanks for your kind words! Regarding the balsa, typical hobby balsa will not work. The tubular orientation is parallel to the surface in these boards. End grain balsa is specifically fabricated as a core material with its vertical grain orientation. It also makes for nice speaker panels if you have any left after your project.

[@YouTubeDoxedMyRealName]

Perfect timing. I was about to buld a light weight structure.

[@larrygodbold3017]

One nice advantage of balsa wood is that you could use fiberglass resin without dissolving styrofoam if you were using that for a core material.

[@TechIngredients]

I think you're confusing polyester and epoxy. Epoxy resin doesn't dissolve Styrofoam.

[@robertchilders8698]

You must use polyurethane foam! The styrene In polyester resins quickly dessolves styrofoam!