RDWorks Learning Lab 164 Honeycomb Alert

[@MakerFarmNL]

Never would have thought of Acrylic condensate building up inside the honeycomb, causing fire in the end. Thank you very much for this warning video. I will now divorce from my honeycomb for sure as well. Especially since it has never been my "honey" either :-). Thank you Russ for all your fantastic content. You sure have created a giant legacy with these series of videos and we (laser cutter owners) are all very grateful for all your work!!!

[@jensvanhoof]

I've been watching K40 videos for a couple of weeks now and just got mine delivered. I can't believe this is the first video that mentions dangers of acrylic together with a honeycomb bed. Thanks, that has potentially saved my machine and my house in the future.

[@RickEverett]

This is probably the best video yet, Russ! First thing I modded on my cheap Chinese laser was the light, moved from the back to the front. (No More Shining In My Eyes) Next was the little pads I put under the door for better air flow. Next mounted a small, fire extinguisher right to the front of the unit. Going to get a nice sheet of material from work (Machinist) before cutting any more material, and using some risers. No more Honeycomb for me....Brilliant as always, Russ. Thank you again, for all of your work! Rick.....In London, Canada.

[@ericdekeersmaeker5780]

Thanks I found this only recently, but I wrote an article about it in our diode laser group. With a link to this video. These video’s are priceless. Thanks.

[@samlenlap]

Thanks for showing that machine i just realized how dengerous these machines can be I'll always remember the two things that you said at the end Thabks Russ.

[@kennethzaremski5111]

Thank you so much for this informative video and commentary! I needed to know this as my engraver is on its way and I'm looking into accessories.

[@SarbarMultimedia]

Hi Kennneth You must not be scared of honeycomb, just understand that acrylic is a potentially dangerous material if it gets too hot. ALWAYS stay with your machine if you are cutting ANY material. Engraving is much safer. You may think that lots of air through the honeycomb is a good thing but what you dont see when cutting acrylic is what happens to the fumes below the honeycomb.. Again this may scare the pants off you but it is just a video to amke sure you stay safe with acrylic. see kzbin.info/www/bejne/m5Ldao17n9ydnNU Understanding and respect ,not fear, will keep you safe. Best wishes Russ As a new user can I suggest you watch this video series before your machine arrives. laseruser.com/the-concise-rdworks-learning-lab-menu/

[@na5y]

You can only get Crunchies from specialty stores over here. I miss them terribly! Interesting video - thank you

[@andyspoo2]

A tip for some:- The metal sheet I ordered was too shiny. I used my PCB etchent, Ferric Chrloide (FeCl3) which is used to remove uncovered copper from circuits. Just rub this acid (with gloves) in swirling motions over the metal. Leave it 15 mins or so and then wash off.

[@turboflush]

Mine came with the blades. I surprisingly like it. My cuts are large enough that they dont fall. I will still order a steel honeycomb for possible future use. To fix the gas collection problem.. Your honeycomb needs grooves cut in the top. This would allow the pockets to escape. Periodic cleaning is a must. Just in one month i have clogged the air filter and the blades have gunk on them.

[@DwightStebner]

this acrylic condensate, would it not be Acetone?

[@SarbarMultimedia]

I am not a chemist but from everthingi know and have experienced, acrylic is very analagous to H2O. At room temperature it is a clear solid just like ice. At 1C ice changes state to lquid water . At 160 C acrylic changes from solid to liquid acrylic. At 100C water boils off into micro liquid particles (steam). In the same way, liquid acrylic boils and evaporates as Methyl methacrylate, micro particles . Steam recondenses on a cold surface so does acrylic . If you blow it back onto the material surface with air assist the hot vapour will stick to the surface as it cools to a solid . Under the correct circumstances it is possible to cool the acrylic vapour before it hits the material surface and ithen just settles as a thin film of solid dust that can be wiped away with a dry cloth. I know that you can use acetone to dissolve acrylic but an not aware that any by-product of acrylic decomposition creates acetone. Quite the contrary. Acetone is used in the prodcution of acrylic (MMA) and is therefore most unlikely to return as a decomposition product.. Acrylic is basically a hydrocarbon and if you reheat the vapour to higher temperatures then it decomposes into combustable products. Great question Thanks

[@jankarlsson8927]

This was really an eyeopener. Thank You!

[@SarbarMultimedia]

Hi Jan You may like to look at this also kzbin.info/www/bejne/m5Ldao17n9ydnNU Best wishers Russ

[@rjlatheart]

thanks Russ for showing the real world!

[@jakesaari7652]

I use a small bed of nails for cutting things like acrylic. Much better ventilation and no need to deal with spacers. I reserve the honeycomb for jobs that require more support eg. fabric. Any suggestions for removing condensate from aluminum honeycomb? Maybe just burn it out with a torch every once in a while?

[@Damalycus]

What about reflections? Does the steel plate not reflect laser and mark the other side of your jobs? I avoid using any table where it's possible, and mostly hand my workpieces. I'm thinking of making a pin or needle table.

[@SarbarMultimedia]

Mild steel is in itself only about 65% reflective but because it is raw cold rolled steel and it is a matt finish the reflection gets rapidly diffused. You only need to be about 3 or 4mm above the surface and you will not suffer reflection of any sort. If you support your work about 12mm above the surface and cause a crossflow of air to rapidly move below the work and remove all fumes. If on the other hand you prefer to not have fumes condensing elsewhere in your machine or extract system you can keep the gap small. In that case you will condense the fumes on the cold steel plate see from 5:20 kzbin.info/www/bejne/jJDImXp7apalfpY I also made a pin support system almost 5 years ago and i still use it regularly. kzbin.info/www/bejne/oX6ng614j7mKb8U Best wishes Russ

[@Damalycus]

@@SarbarMultimedia thank your for such detailed answer. Cheers!

[@Foche_T._Schitt]

Aluminum is very reflective. I didn't see you elevate the work on the honeycomb. It could be the aluminum honeycomb is reflecting the laser back at your work and leaving the marks.

[@DalyMalcolm]

Nuke Censorship I think he said that

[@surferdudemi]

The honeycomb (at least on our machine) is steel. We use magnets to hold down light material that might be blown away by the air blast in the nozzle.

[@andyspoo2]

@@surferdudemi Regardless of what it's made of, the main issue is that you cannot reliably clean the inside of the honeycomb and it is likely at some point to ignite.

[@surferdudemi]

@@andyspoo2 Ours has not ignited in 6 years of use on two machines.

[@andyspoo2]

@@surferdudemi My house hasn't been in a flood or burnt down in decades. But I'm still going to pay house insurance and use smoke alarms. You're welcome to play Russian roulette, but I'm not going to! :-)

[@pahuns9398]

Hi Russ, I find your videos to be a wealth of detailed knowledge and thought process. To help reduce the smoke condensate problem I have been toying with the idea of using a solid steel plate with work material raised with spaces of some sort (probably magnetic), BUT with active cooling to the bottom of the steel plate. Simply brazing, or soldering with silver , some copper tubing to the bottom of the steel plate and having the return water from the laser then go though the bed plate tubing then back to the chiller. This, I think, would allow for easy wipe off of the smoke condensate after each job or when deemed necessary. What do you think? I would very much appreciate your thoughts on this.

[@SarbarMultimedia]

I like the thought process but additional cooling with water is unnecessary. The golden rule in life is to keep it simple . If you use just a sheet of 2mm mild steel, the thermal capacity and thermal transfer rate will far exceed the heat you can inject into the steel. You may think that aluminium , copper or brass would be better at heat transfer and you would be right BUT the problem is the REFLECTANCE property. The are all more than th 95% reflective so any energy passing through your kerf will reflect up onto the back of your work. Less than 5% will go into the table That is why I use mild steel for my baseplate , It is still pretty reflective at about 65% but so you still have to be careful about reflection. . If you have a 100 watt tube for example then any 100 watt beam passing through your kerf will only be painting lines on your.table that are about 0.5mm wide and with 35 watts of power. The airflow through your machine will naturally keep the surface cool.. The tar condensate , or acrylic condensate will not just wipe off .it will need to be assisted by acetone. If the table start to mark up, just run an orbital sander over it using a coarse grit.. IF YOU FEEL THIS SIMPLE FIX IS NOT WORKING , BY ALL MEANS TURN IT INTO A PROJECT best wishes Russ

[@pahuns9398]

@@SarbarMultimedia Thanks Russ for such an in depth response!

[@joeblogs4146]

Brilliant stuff. One idea I was thinking of is on the inside of the machine at the front end "located on the area of the door handle ( could a 12volt mini fan from a old computer or eBay make any difference or improvement to forcing the air out of the inside of the machine without having the door open? as my blue and White K40 that hasn't even been used yet because I haven't ammeter installed "and" might I say that without watching these videos my so-called 40watt K40 tube would be destroyed, oh! It's now "spot on 3am in Liverpool my wife is asleep next to me as I continue to get amazed watching a genius at work! So I've got half a can of carlsberg left and been watching these videos since 4 - 5pm so I better get my head down in case this snoring ...... Wakes up, No I lover her to bit's really 😰 😁😁😁 Oh! Goodnight!

[@SarbarMultimedia]

Hi Joe The problem that many do not understand (including 90% of Chinese machine designers) is that to extract fumes you MUST allow clean air in. A sealed box like the K40 is nothing more than a vacuum cabinet.....except that it is so badly manufactured that that there are air leaks round the door. You will need to prop the door open with a couple of 25mm blocks to allow air to pass THROUGH your machine. Ideally you are trying to get air flow ACROSS your workpiece. Extract suction alone will not achieve this you need a directed air jet caused as you suck air in through the front door. This effect is well illustrated by holding a candle flame at arms length. Suck as hard as you can and in any way you can imagine. Can you extinguish the flame? No. However, gently blow a directed stream of air at the candle and the result is completely different. That is what that stream of air coming in through the front door will do. Maybe four 2" pc fans in the front wall of the cabinet will do the trick also. Best wishes Russ

[@derrickstewart5554]

Hello Mr. Russ, Hope all is well. I was wanting to know how thick the piece of metal you use on the table is and is the size 11 3/4 x 19 3/4?

[@SarbarMultimedia]

Provided it sits inside the table brass bushings if you have a China blue machine and covers all the slots in the original table then it will be OK. The thickness will be fine at 1.5mm but on my Tangerine tiger I used a more stable 2mm thick. Best wishes Russ

[@derrickstewart5554]

@@SarbarMultimedia Thank you again kind Sir.

[@robertjones1730]

I had a fire in my machine once and since I was there to see it, I just picked the honeycomb up out of the machine and took the fire outside and put it out, no damage to my machine. Big tip here: sodium hydroxide (Industrial Purple) cleans the wood residue off the screen like magic. Looks like new again, 1 part to 10 parts hot water soaking, As long as it's a steel honeycomb, sodium hydroxide eats aluminum

[@SarbarMultimedia]

Hi Robert Thanks for the great tip. Yes I do have a steel honeycomb but sadly it has an aluminium framing. The second issue is more interesting. Acrylic, the villain in this video , is unaffected by NaOH. See this chemical resistance chart marketing.industrialspec.com/acton/attachment/30397/f-006b/1/-/-/-/-/acrylic-pmma-chemical-compatibility-chart-from-ism.pdf All best wishes for the New Year Russ

[@TheBruster1]

Excellent info as always Russ, You have got me thinking about your dilemma with your laser beams focal point. You seem to have covered and worked out everything, presented very well i might add, regarding the main beam strength as well as the type of bell curve for each lens used. I wonder what the beam would be like going into plywood or MDF? The only way i can think of seeing what the cut would be like would be to do your shots along an edge then check it with a microscope. The acrylic is a great medium for visuals but i wonder if the acrylic being evaporated is distorting the beams cut? I will have to ponder this more, keep up the excellent presentations. I have learned a lot from your videos on laser cutting. Thanks

[@russsadler3471]

Hi Bruce Although I showed the beam piecing through acrylic you do not have to anything special to see that same effect in plywood or acrylic.Just run a cut across a 25mm wide piece of material and offer the two cuts back together. You will find the faces are virtually parallel. And that is my real question, Regardless of material, what is the mechanism by which a diverging beam of energy can punch a parallel cut through material? Best wishes Russ

[@kennuimuffins2426]

Very informative video. I've been doing the exact thing in the melted machine, using small spacers to prevent flashback. Do you have a recommended setup for cutting 3-6mm acrylic? They will sag unless evently supported from below and hitting an acrylic piece below the main sheet will result in residue on the egde. I was using 1mm thick card which left no marks at all, but it's extra work cutting up and positioning those pieces for every sheet. Bed of nails seems like the most efficient, like in your earlier videos but it's too dangerous for regular work. I haven't yet purchased my own laser yet, just doing all the research I can now. Thanks.

[@SarbarMultimedia]

Hi Kennui 3 mm thick acrylic is surprisingly stiff. As you may have seen from my videos I hate honeycomb and always work with a flat steel sheet. This allows the airflow to come under a gap in the font door and flow backwards across the top of the work for engraving and under the work for cutting because I always use stand offs of some sort. I often use 400x600 sheets of 3mm and I have some 20mm diameter discs of 8mm thick acrylic which I use to support the long edges (3 back and 3 front I also drop one somewhere in the center This is adequate support to stop initial sag with a 2" lens you can tolerate over 1mm of sag/out of focus. However as you start cutting pieces out of the sheet the weight distribution of the sheet changes and additional sag can result. To overcome this I will put one or two tags (0.1mm bridges) to stop components falling out . This keeps the sheet balanced and when the beam passes over the acrylic center support I see no problem on the edge at that point. just a neat cut into the support disc.. I do exactly the same support method for 6mm thick acrylic but this time I do not tag items into the sheet because the droo is guided for all but the last 2mm and it is very rare foe items to fall into the cutting path of an adjacent component. The bed of nails is the ideal solution but it is a bit tedious to set up. I am just about to experiment with a quicker and easier flexible nail support system that I have copied from a friend of mine.and adapted. I will be showing it in a future video. Best wishes Russ

[@kennuimuffins2426]

​@@SarbarMultimedia Thanks for the reply, really appreciate you taking the time to do so. I'm very interested in Trotec's square grid table, it looks white and is supposedly good for acrylic, any idea what material or coating they use? Haven't been able to find good info/videos on it. Another system I have found is using metal rods arranged like a slat bed. In theory this should be easier to clean as well. Looking forward to your future videos.

[@SarbarMultimedia]

@@kennuimuffins2426 The Trotec grid you have seen is just an acrylic ceiling light diffuser/grill It is known as eggcrate. You can Google it but beware they are not all acrylic. Many are styrene and a bigger fire hazard than acrylic. For example www.edee.com/eggcrate.htm It's just a honeycomb support in acrylic and has all the closed cell trapped fume issues associated with metal honeycomb. Here it is. I have seen and used it but would not recommend it because it prevents rapid fume evacuation from below your cut. Best wishes Russ

[@dave-j-k]

Hiya Russ, that burnt machine is the same as my one, they are all clones of a RedSail machine, mine is the more common red and black model. Its been a good work horse for a year and still on its original tube. I cut a lot of card and that honeycomb is junk for that, i have some thin (0.3mm) strips of aluminium cut which i stand on edge to support the work, far better and can be moved around. What sort of extinguisher would be best for a cutter in a house? I prefer Halon but its banned now, maybe Co2? As you said, the golden rule is never walk away.

[@SarbarMultimedia]

Hi Dave I have a CO2 one I bought from Amazon. www.amazon.co.uk/Carbon-Dioxide-Fire-Extinguisher-FireShield/dp/B00NPWP6GI/ref=sr_1_2_sspa?keywords=fire+extinguisher&qid=1552122012&s=gateway&sr=8-2-spons&psc=1 I always use my pin table for card cutting. There is over 25mm air space below and unimpeded airflow Best wishes Russ

[@CiaranWhelan]

I wish you lived in South Australia. I would be doo happy to take this cabinet and build a new laser into this. Love this video.

[@SarbarMultimedia]

Hi Ciaran I would quite like to live in Southern Australia as well!! Best wishes Russ

[@robertsmagala2886]

Thank you for this informative video. I try to catch up on your previous ones but there is so much material to go through... Anyway, quick question: we use a 1600x1000mm 130W laser mostly for cutting fabric. It came with a honeycomb table which is a pain to clean and we see the poor airflow whenever we cut HDPE. Could you recommend a proper cutting surface for fabric? Standoff obviously won't work for us. I was thinking about a steel or aluminium table with bigger holes than the honeycomb.

[@SarbarMultimedia]

Hi Robert This is an ongoing learning journey so there is 3.5 years of getting to grips with the machine and the technology. Starting from the end and working back may be confusing so maybe jumping back 20 sessions at a time and then working forward may be a better strategy . Much as I hate the honeycomb it has its uses for some people. Soft floppy fabric is just such a use if you are doing one offs and specials. However if you are doing repetative shapes there may be alternatives. Attach you email to another comment and I will reply with spme questions and remove your comment/email from public view. Best wishes Russ

[@mikeboehk2307]

Hi Russ - as always thanks for the very informative information and the humor and practical thinking you always share. I've been looking at replacing my honeycomb for other reasons - it sags in the middle and the flash burns ruin otherwise pretty good looking cuts, but it's built into the frame of my laser bed. I think I can just cover it with a sheet of steel which should block any vapors from entering and certainly prevent any laser ignition. What thickness and type of steel do you use on your lasers? Mine's an 80W Reci, so not overly powerful. If I support the sagging middle so the sheet stays level, what thickness would be reasonable in your opinion and any difference in steel types as far as use with this wattage laser?

[@russsadler3471]

Hi Mike All metals reflect the CO2 laser beam. However, some are better than others hence we use gold plated or molybdenum mirrors on our machines. Metals like aluminium, copper , silver and tin are VERY reflective 98% plus. Stainless is close behind at about 95% . Mild steel is one of the less reflective metals at about 65%. If you use hot rolled steel (black/oxidized finish) that keeps the reflection very low because metal oxide is NOT metal and there will be little reflection.. There is only one problem with hot rolled steel, it is shipped from the mill to distributors on a huge coil that has to be passed through rollers to flatten it before being chopped into sheets. Getting hot rolled steel that is nicely flat will be difficult. For the size you require you will probably be fine to use hot rolled . Take your old honeycomb from the frame and pull your sheet of steel down onto the frame with countersunk screws. I would use 2mm thick steel. I chose to use cold rolled steel because it tends to be naturally flat. It is at that 65% reflecting vaue BUT the slightly orange peel surface causes the beam to scatter and diffuse any reflections. You can clean either surface with 3M industrial abrasive pad if it the grunge gets burnt on but usually you can use acetone to clean of fresh deposits.. Best wishes Russ

[@stephenheller635]

Interesting warning about the use of honeycomb to support acrylic. I've thought about using a sheet of mild steel as you have but I am concerned about the steel reflecting the infrared energy from the head through the acrylic (or other material) back into the head and damaging the lens. Not long ago I recall you tried etching stainless steel, which did result in damage to the lens. Does mild steel pose a problem here?

[@SarbarMultimedia]

Hi Stephen Stainless steel is naturally about 95% reflective , hence I was doing something risky when I did "naked" stainless engraving. Mild steel is quite different. Firstly it is only 65% reflective and secondly it causes scattering of the light. The concern you have of IR reflectiing back through acrylic is ill founded. There are only 3 types of material that out 10.6 micron light "sees". The first is metals. All metals reflect IR,. some more than others . The second is a very small group of exotic salt-like compounds (example is zinc selenide) that allows the IR light through unhindered. The third group is EVERYTHING ELSE. The molecules of this group will be stimulated to various degrees and heat up. That includes acrylic. It may appear transparent to visible light but to IR light it is completely opaque so there will never be any refelection back to the lens. Hope this allays your fears Best wishes Russ

[@LaserWoodShapes]

That is why I stopped cutting acrylic and focus only on wood. Even with that decision, it's important to clean the honeycomb regularly to get all that black and brown off of it since the laser will hit that old stuff, and cause more heat, smoke, and fire (think re igniting a charred piece of wood)

[@SarbarMultimedia]

I agree that wood fumes are also sticky, nasty and may also be prone to reigniting, The reason I focused on acrylic is because 6 out of 6 fires that I know of are all acrylic based.machines. My 1% usage of honeycomb is never going to expose to the risk but when I cut wood on my steel base plate I often get a serious sticky brown condensate even with my good cross flow under the work. The great thing it is obvious and just a quick wipe with acetone fixes the problem. Thanks for reminding others of the wood residue danger. Best wishes Russ

[@LaserWoodShapes]

@@SarbarMultimedia your honeycomb is relatively clean of wood residue.. on our production machines that can get solid black edge-to-edge. I'm sure that others run their machines like I do and are pushing the dirtiness past recommended amounts.

[@andyp6909]

@@LaserWoodShapes What do you use to clean your wood residue from your honeycomb? I've tried all sorts, oven cleaner seems relatively successful but still hard work. My bed is 600x900 and not found anything big enough to allow me to let it sit and soak which I'm sure would make it easier

[@LaserWoodShapes]

@@andyp6909 degreaser for day to day cleaning and a sand blaster every other month to restore them to 100 percent.

[@andyp6909]

@@LaserWoodShapes thanks, I'd not thought about sand blasting. Will see if I can get someone local to do it

[@Michael-lo3ht]

Excellent. Gives food for thought about residue no matter how it accumulates. I don't know if this helps any or not. But would adding say a thin metal rod evenly spaced going across the honeycomb? That way it lifts the material enough to get air from front to back and down through the honeycomb? There will still be residue, but at least maybe have flow enough to keep it down. I would say if anyone does use a honeycomb that it's cleaned or replaced regularly. I get the feeling you're going to have a better solution coming up anyway. lol

[@SarbarMultimedia]

Hi Michael You do not need airflow to pass easily thriough honeycomb and starigh out the extract duct, what is the point? No you need to MANAGE the flow over and under your work. I VERY occasionally have to use the honeycomb table but for 99% of jobs I use my flat steel plate bed which clips into the machone. This forces the airflow where I I want it to go and that is through a nice 30mm gap under the front door, across the top of the steel plate table and then down through a grill at the rear of the table. There may be 5% leakage over the edges of the table but that is inconsequential. In this way there are no dead spots for fumes to accumulate. Cutting any sort of organic material is a heat induced chemical rection producing tars and resins that will easily condense onto the first cold surface they encounter. Acrylic is a completely different mechanism akin to ice and water. It is solid at room temperature, liquifies at 160 C and eveporates at 200C. It is just acrylic vapour and has not changed chemically. It will also easily condense and solidify on any cold surface . It so for this reason that I use a cold steel plate to work on. See this unissued video to illustrate what I mean.. kzbin.info/www/bejne/b3uTqJugaM6KbZI Best wishes Russ

[@Michael-lo3ht]

@@SarbarMultimedia For myself I wouldn't use a honeycomb. Guess what I'm saying is if someone insists on using one then maybe raising the part up enough would at least allow air to flow and keep the honecomb cells from filling up with fumes. Like you showed there are better options than a nasty honeycomb anyway. Thanks As always I'm learning a ton from your videos.

[@tweakgames]

I love these episodes. May I ask if you have any more information on that nozzle/tube setup on the light blade? Is it a stock unit? An upgrade? Anybody know where I can get one. I love how easy it is to adjust. Thank you.

[@SarbarMultimedia]

Hi All these Chinese machine are assembled from a big Lego kit of standard parts that they buy from a big laser supermarket. There are certain basic standard machine designs that the Chinese government authorize and subsidize but the build factory can choose the discrete components (often the cheapest) that go to make up that machine. One such laser supermarket that I have come to trust is Cloudray You will find lots of better quality items on their website. It depends on what head you have at present if it will take one of the standard diameter lens tubes available see www.cloudraylaser.com/collections/nozzles-lens-tube or maybe you need to buy a complete new head assembly (C series) www.cloudraylaser.com/collections/laser-head-mirror-base-1 Best wishes Russ

[@acdii]

Here, all this time, I was thinking Honeycomb was the way to go as long as the acrylic was elevated above the comb to prevent reflection. The one I am getting supposedly has two different platfoms, guess the Honeycomb will be relegated to acting as a shelf after seeing the destruction!

[@SarbarMultimedia]

99% of th time my honeycomb is acting as a barrier to stop the dogs getting into my workshop. For 1% of is life it has uses. For example if you want to cut some flimsy cotton material or such if you are a dress designer ( not one of my skills!!) or cut a jigsaw puzzle (sadly I have not found another way) then yes it can very occasionally be invaluable. Whether it be plywood or mdf fumes they all stick and build up in your honeycomb. It's just that acrylic build up is a lot more liable to catch fire, particularly when you maybe cutting thicker acrylic very slowly and the excess energy gets enough time to add lots of heat to your residue. Of all the fires reported to me , they have all be machines that are predominantly acrylic cutting. This is just a tip to be wary if you are doing lots of acrylic work , NEVER walk away from a CUTTING process. and maybe think about swapping out your old honeycomb every 6 months or so. Just examine it carefully and maybe you can rescue it by torching it with a blowlamp to burn off the residue safely away from the machine. Don't be frightened, just be cautious Best wishes Russ

[@acdii]

8 months later and I am still fine tuning the laser. I have been using the HC for what I am doing, which is cutting balsa and lite ply, and though I haven't done much since I got it, what I have done has left a smelly residue on the comb. I also found it shifts around, and isn't easy to secure panels with, so need to replace it. Underneath it has aluminum slats, so those will work well with the wood, but difficult to secure the material to is. If I put a metal sheet, how does it effect the cuts on plywood and balsa?

[@izaberipoklon]

If I want to cut a hole in some materials, to fit in it material 3mm thickness, how do i know what dimension to draw do rd have any option for it? When I draw 3mm he cut let's say 3,2mm, you understand me I guess... Or I whill learn that by expiriance

[@SarbarMultimedia]

Hi Zoran That is a challenging question because it depends on so many factors.. Draw a 25mm circle then cut it out at what you think is the correct (or a good) speed and power. Now measure the hole you have produced and measure the disc. Subtract the disc dimension from the hole dimension and the difference may be 0.4mm That means tour effective cut width (kerf) is 0.2mm wide. This means that for a perfect fitting disc in your hole you need to add 0.2mm to your disc. RDWorks has a tool for doing this. It is toward the right end of the top toolbar and is called OFFSET POLYGON. This allows you to offset your shape by a fixed amount inside or outside the original . HOWEVER, if you change the speed of cut, the fixed power you are using will affect the kerf width because the burn will happen in the cut for more or less time. If you run almost as fast as the possible so that your disc JUST falls out you will have produced a slightly tapered cut where the kerf may be 0.2mm at the top and 0.05mm at the bottom.. The focal point of the lens should ideally be on the surface of the material you are cutting, if it is not then the kerf will change. The focal length of the lens will change the kerf. The longer the focal length, the bigger the kerf will be. The efficiency of your air assist will affect kerf width also.. The kerf width on a 6mm hole will be bigger than on a 20mm hole because the 6mm hole will never reach your program speed and will therefore be burning more.. Change the material you are cutting or the thickness you are cutting and everything changes. There are no absolute rules you can follow other than to do some tests with the materials , speeds, power and lens you intend using and then measuring both parts as I described earlier.. I think challenging is the correct word to use because no matter how much experience you gain it will only teach you about your best guess. If you are always cutting 3mm mdf for instance and always use the same lens, power and speed, you may be able to record these factors and reasonably be able to predict the kerf. Best wishes Russ

[@izaberipoklon]

@@SarbarMultimedia thank you for answer, all the best!!

[@andyspoo2]

Brilliant! Did you ever try the laser tube from the burnt out cutter?

[@SarbarMultimedia]

Hi Andy No. I did examine it and apart from the smoke/fume build up on the outside it looked relatively OK until I checked some plastic covering/insulation on the HV end that had distorted with the heat. This was only a 40 watt tube and of no real use to me. It was sent to the recycling centre along with the rest of the top half of the machine. I kept the base frame and wheels and made myself a mobile workbench. Best wishes Russ

[@brianfoster1504]

Wouldn't you get the same result if you used the 10mm supports with the honeycomb?

[@SarbarMultimedia]

Hi Brian Simple answer no. The air flow will find the easiest way in and out of the machine. So most of the airflow will down and through the honeycomb before its much more than 6" inside the front door. Many machines like my China blue do not have ANY gaps for airflow IN so I have to jam the door open a bit.. By blocking off the honeycomb you are MANAGING the airflow to go where YOU want it. Best wishes Russ

[@dbrgn]

Hi Russ, thanks for this video! I'm thinking about getting a Gweike laser. They sells their machines with both honeycomb and "knife blade" platforms. Do you have any experience with those knife blade platforms? Are they any good?

[@SarbarMultimedia]

There are two types of knife blades supports. Fixed in a lifting frame and stat position across the top of the machine but removable singly. Thes removable ones are usually a poor fit and any work placed on them could wobble/move by 2 or 3mm. I would be pretty sure this is what GW would supply having seen a couple of their machines. . Although I hate honeycomb it does have it's occasional uses. As you will see in this machine I have the best of all worlds. I have a fixed frame knifeblade bed which again I rarely use, that is my Z axis table. I have removable honeycomb that sits on top OR I can replace the honeycomb with a flat steel surface which I use 95% of then time. Why? Well, it's all to do with air flow management, something that zero machine manufacturers pay any heed to. Take a look at this video from about 24 minutes onward and I will explain what airflow managment is. kzbin.info/www/bejne/d3nRe2WNrbOia7M It is vitally important and you may have implement your own method on a GW machine. That is why I indicate that maybe the more stable honeycomb well be best (is it raising and lowering?) because you can easily place a sheet of steel on top to FORCE airflow management and have a nice stable work surface. It does mean you will have to raise your work by 10mm or so to let airflow below your work. You might like also view this kzbin.info/www/bejne/m5Ldao17n9ydnNU Best wishes Russ

[@dbrgn]

@@SarbarMultimedia Thanks Russ for the quick and long reply! Yes, the machine I'm planning to get has a motorized bed/table. I think I can retrofit a steel plate as an alternative to the honeycomb.

[@SarbarMultimedia]

@@dbrgn I'm suggesting to wait until the machine arrives and then fit a removable steel plate that sits inside the honeycomb edge frame and leaves a 2" air gap along the back edge to draw air down in a controlled manner. In that way you have options. Best wishes Russ

[@muddundee]

@@SarbarMultimedia We had a Laserite machine at my last school with knife edge bed, it was excellent with no movement of anything placed on it. Bars easily cleaned once every couple of weeks in a bucket of hot soapy water with a scotchbrite pad. Gotta keep them clean!

[@russsadler3471]

@@muddundee Yep. I have a fixed knifeblade bed under that removable honeycomb bed. and it works well for some jobs..However it make proper air flow management through th machine abysmal. . Since that video 2 years ago I have learnt of 4 more machine fires caused when cutting acrylic. Most of the time I use my flat pale steel bed. Best wishes Russ

[@TimRobertsonWoodturning]

Hey Russ, what is the steel that you are using (Type and thickness)?

[@SarbarMultimedia]

Hi Tim All metals are reflective to 10.6 micron light to some extent. ordinary mild steel is in the lower region at about 65%. There are different finishes of steel with various plusses and minuses. depending on the size of your machine table.For my 300x500 and 600x400 tables 1.5mm (16g) uncoated cold rolled steel has been used. For this relatively small size the sheets are very flat and do not bend when cut to size from a larger sheet. If you are bigger than this, maybe 1000x700mm or in that region, I would be using 2mm (14g), Cold rolled steel has a fine orange peel finish wich is great for scattering the reflected light thus breaking down the energy density. On the other hand Hot rolled sheet (usually black finish) has an oxide layer on the surface which absorbs the energy and very little is reflected. With such obviously great properties this seems a no brainer. . Sadly hot rolled material hides lotsof residual stresseswithin and is shipped from the mills in huge coils that have to be passed throught straightening rollers before being cut into sheets. The sheets may be flat but when you start cutting into the sheet stresses are released and your 1000x700 sheet may finish up with a 2 or 3mm bow in it. If you can secure it to a decent table support frame with countersink screws and pull it flat then this is probably the best (and cheapest) option. For most tables 2mm will be thick enough, Best wishes Russ

[@TimRobertsonWoodturning]

@@SarbarMultimediaThank you Sir, mine is 1300x900 and I have people asking me to cut cloth for COVID-19 mask. I will see what I can purchase from local metal shop. As always thank you so much for everything you share with me and so many others.

[@SarbarMultimedia]

@@TimRobertsonWoodturning Hi Tim Much as I hate to admit it, fabric is about the only thing that is best done on a honeycomb table. I dislike honeycomb intensely but I think it was just this application in China that started the honeycomb revolution. There is little else it is good for. However, If you have a honeycomb table you have been using for other things it will be in a bit of a state and any beam passing through the fabric will not be sensitive to passing over the edge of the honeycomb cell (that's a minor problem that will not show on most fabrics) but that excess energy will cause your crap within each cell to burn and create fumes and that will mark and create smell on the underside of the fabric. You may really be looking for clean steel honeycomb. Best wishes Russ

[@TimRobertsonWoodturning]

SarbarMultimedia thank you, with that information I may take my honeycomb table out, pressure wash it, dry it and give that a try.

[@SarbarMultimedia]

@@TimRobertsonWoodturning Hi tim Pressure washing will help but it may also distort it. Try it carefully. I ave heard of people having success with alloy wheel cleaner and bbq cleaners, Caustic oven cleaners also work but they are dangerous to use and your table is big. A thought has occurred to me. If you plan to run the same program many times, draw your program in absolute mode so the beam will always follow exactly the same track on the table. Drop he table about 2" and run the program a few times quite slowly to BURN off the debris along the beam path. This may be the quickest and cleanest way to solve your problem. Best wishes Russ

[@TMS5100]

And that folks, is why you never ever run a laser cutter unattended. Ever. There is absolutely no excuse.

[@khaledhalabi2430]

Fantastic work ...thank you so much

[@mcget123]

Hi Russ Your videos are excellent. Its the only real help i have had since buying one of these machines. I bought the bigger "60w" Model of this machine and am having a lot of trouble with the laser tube arcing internally to the piece of steel where the beam exits the tube. I bought a replacement and straight away the same problem persists. I always use distilled water and have flushed the system and checked the earth wires. Can you give me some guidance as to how to fix this problem? Im sure you are busy with all these comments but you are the only person i can think of that can help. The seller has no clue. There are no videos on youtube with a solution. thanks Tom

[@SarbarMultimedia]

Hi Tom This may require some email communication because what you have is not normal and you may have have to send me some pictures or video. Add your email to another comment and I will reply. I will also delete your comment from public view Best wishes Russ

[@spawnytraxx]

much appreciated video thanks again russ

[@Martin-ll7jc]

Great advice

[@weesew50]

Hello Russ, Let me start by saying I discovered your videos while researching CO2 lasers. You are the only reason I felt secure enough to purchase a 60 watt machine from China. Your videos are priceless, and I've been watching them in order, while also jumping ahead to interesting subject videos . This video about honeycomb tables is very valuable and shows the possible danger of using one. With that being said, I plan on removing my honeycomb before I ever start doing any type of cutting/engraving. Is mild steel a better choice than aluminum? I believe I know the answer to my next question, but can you use Midas Black Max, a metal darkening chemical to lower the reflect ability of the steel? I'm currently building a room in my woodshop to isolate the laser from all the dust producing equipment, and also waiting to purchase a S&A CW5200 chiller before I start using the laser. Thanks again and I look forward to your fiber video's as my next purchase is a 50 watt fiber with a Raycus QB laser and a Sino Galvo SG78210 head. I look forward to your reply. Bill H.

[@SarbarMultimedia]

Hi Bill ALL metals act like mirrors at 10.6 micron wavelength. It is all to do with the crystallographic structure of metal. However some metals are better mirrors than others. For example, copper, aluminium, silver, gold and platinum are about 99% efficient and this only drops by a couple of percent if you scuff or roughen the surface. Stainless steel is about 96% efficient and mid steel is about 65% and the natural orange peel effect on the surface of cold rolled mild steel does cause some beam scattering (reduction of energy density.) Hot rolled mild steel will be a bit better because it has a thin layer of non-metallic oxide and non-metals absorb the IR light. However hot rolled steel is usually not flat. Treating the surface of metal will have the effect of absorbing the IR energy but it may need regular treatment if you damage it. A comment from Andy Parry may be useful to note also. Best wishes Russ

[@weesew50]

Thank you for your reply. Can’t wait to see your fiber laser work.

[@Lowbattery_fpv]

hi! how you? happy to meet you again here

[@SolarMillUSA]

You are such an amazing wealth of information. Thank you.

[@DaniMora81]

Thanks for the video !

[@DalyMalcolm]

I was planning on using a honey comb base. I won’t now

[@SarbarMultimedia]

Hi Malcom If you are cutting thin fabric or in my case it was an acrylic based jigsaw puzzle there is no sensible alternative to honeycomb. So yes I still have a very distant relationship with it for odd jobs but because mine is removable is only on an "as required" basis. Yours is a wise decision not to base your machine around it It puzzles me why the Chinese (and even the "big boys" insist on using it. I feel like a bit of a Ralph Nader with this mission. Best wishes Russ

[@kurtlyons7123]

I just watched this video on the "downside" of a honeycomb table. I see yours is a steel top, but would 6mm or 12mm thick aluminum do the same job without any additional hazards? Thank you in advance.

[@SarbarMultimedia]

Hi Kurt The problem with all metals is that they are reflectors. Some are much better than others. Aluminium is one of the best along with silver,copper,gold,platinum and molybdenum. When you make a cut, the beam does not lose its power just because it appears out of the bottom of the cut. That beam gets reflected off any metal it strikes. That is why the flashes from honeycomb cause damage to the back of your material and why that "pass through" beam can ignite stagnant pockets of fumes below your work. see kzbin.info/www/bejne/m5Ldao17n9ydnNU Aluminium can be a great baseplate if you anodize it because you are converting the metal surface to a non-metal (aluminium oxide) which absorbs the light rays and converts it to heat. However. if the energy density is too high you can burn through the aluminium oxide and expose raw aluminium again. . I use ordinary cold rolled mild steel because the reflectivity is about 70% (still quite high) but the natural fine orange peel finish causes scattering of the beam as it reflects. This greatly reduces the potential damage the reflection can do. If the surface gets a bit caked with debris that cannot easily be removed with acetone, then it can be removed with an industrial grade abrasive pad. The multiple scratches only helps to scatter the beam . Best wishes Russ

[@mamoonnaseer1886]

Loved your speechless moments and thanks for showing us the danger associated to laser machine

[@arieagung]

From honeycomb snack to burned laser machine forensic....

[@ruftime]

Thank you!

[@pierrick1705]

Your left and right audio tracks are not at the same level on your video editing software.your left is less loud than your right.

[@SarbarMultimedia]

It's more likely that I am standing on one side of the camera and the stereo mic is doing what it should do.. Thanks, I will investigate, although this is never intended to be a Hollywood production. Best wishes Russ

[@letsfixit1594]

Great info thx.

[@Luis__Martin.]

What a machine penalty

[@RGCbaseace]

I never tried that aluminum honeycomb cant find a big enough section of it I use ceramic tiles 15 of them my 50watt laser has a 12x6 foot cut area I use little tiles as spacers i mostly cut F111 nylon and a fabric called zero p Just f111 with silicone coating on it nylon does the same stinks just as bad too I cut quite abit of it i do art work on modern ramair parachutes but my machine is rather large it also has a spindle too be binge watching all your vid love them

[@SarbarMultimedia]

Hi Jerry. I would guess your machine is very low fire risk because unlike MDF and particularly acrylic, nylon tends to melt rather than vaporise or oxidize (burn). Your material is also very thin so although there may be smelly white smoke your machine has no crevices where any condensing fumes can build up. I also think that any residues will be hard to ignite with 50 watts because I suspect you run quite fast maybe 20 to 30mm/sec? so any residual energy passing through the material be moving so fast there will be insufficient energy per unit of time to ignite any residues. Acrylic is exactly the opposite ie cutting slow with high power. Your "flat" approach is much safer than honeycomb.because there is always a heat sinking mass behind the material.. Thanks for the interesting feedback about a material I am unfamiliar with. Best wishes Russ

[@RGCbaseace]

@@SarbarMultimedia Yes i believe you are correct although my machine built from 3/4 ply and steel L beam like dave gattons machine got together with Patrick daniels machine had a big angry baby with dual output shaft 1600 oz nema 34s on all axis it can be quite fast 1200 in per min but thats the stupid fast never use danger danger setting i cut f111 at 40 in per same with zp the zp has silicone coating to make the fabric non permeable to air but its also kinda weird the condensate from it is powdery gets everywhere dosen't want to come off even with ipa so i have to use acetone then a vacuum like crazy lol no fire hazard their huh my vacume table seems to have minimized it to an extent but i fear it collecting inside the vac box the thing cost a small fortune its 1/8 aluminum sheet with 9 bagillion 1/16 inch holes punched in it the bottom and sides of the box is backer board and ply ( concrete board for showers) just incase the laser shoots thru one of the holes i tested it at full power for 5 mins it turns black But thats about it no fire ive tried to ignite the nylon condensate it does burn but not as readily as acrylic I was wondering do you still have the files for the rotary device ? Seem very interesting the link say its no longer their ?

[@russsadler3471]

@@RGCbaseace ¬Hi Jerry Add another comment with your email and I get auto copied to my gmail. I will send you the file and also immediately delete your comment/email from public view. Best wishes Russ

[@CallumWK]

Ill take it off your hands and rebuild it! I'll promise I won't use honeycomb in it... I'm in england too!

[@SarbarMultimedia]

Hi Callum. I had already stored it for a couple of weeks before I did the video. It was a nice day when I did the video so I decided that it had outlived it's welcome. I set about it with my slitting disc and decided to save the base frame for a mobile workbench. The rest was at our local recycling centre by the end of the afternoon, Oh not quite all .The air pump and blower went to separate local good homes (both in need) and the HV power supply and controller went to a local makerspace. Sorry to disappoint Best wishes Russ

[@CallumWK]

@@SarbarMultimedia Not dissapointed, it was a long shot! - I am planning to build my own though, your videos have been a great help in some of my design features. This video for example, I always thought honeycomb was the way to do it, the laser cutter I used to use came with one from the manufacturer, but I've seen the light... Figuratively speaking haha.

[@Tuffenough4u]

Two things that you should be aware of is you shouldn't be cutting acrylic with more than about 2-4 PSI of air pressure from the nozzle to begin with. That is what blows the smoke under the bed and it makes for some pretty crappy raster etches as well due to the air cooling the surface of the acrylic to fast, thus causing scan line ridges to harden in place instead of smoothing out as they should be. The second thing is don't buy acrylic without protective film. 99% of acrylic comes with said film on both sides. Don't remove it from the back of the piece before cutting. Only the top where the laser kits it. Knowing those two things alone will drastically reduce your issues and make for better finishes. The honey come does very well for certain materials such as paper where you need it laying across a fully supported bed.

[@SarbarMultimedia]

Hi Acrylic is a unique material. I has all the properties of H2O. At room temperature it is solid(and usually clear). At 160C it turns to liquid and at 200C it turns into acrylic vapour (steam). There is no chemical change just a change of state. Just like steam, when acrylic vapour hits a cool surface it will first recondense back into liquid and then cool further to solid. The next fact to understand is that there are two manufacturing processes for the same acrylic material. They are chemically the same (and act as described above) but have significantly different properties, both mechanical and processing, Extruded acrylic is squeezed and rolled to sheet (like toothpaste from a tube) and cast acrylic is poured between two sheets of thick glass and allowed to set into a flat sheet. Cast acrylic thickness tolererance is huge and extruded is quite small. You can cut extruded acrylic with lots of air assist and it will still give you a nice flame polished edge with no striations. Not so cast acrylic Even with zero air assist you will get striations especially below 3mm thickness Above 3mm you can slow your cut speed by 30 to 50% to allow heat build up within the cut. This allows the LIQUID phase of the material to FLOW and self level on the walls of your cut to get a polished edge. The vapour will ALWAYS flow from the BOTTOM of your cut regardless of air pressure. Never turn your air assist off , just reduce it to a whisper to make sure fumes do not reach your lens. Once you have established a THOUGH cut, there is no longer any material in the way of the beam to absorb energy. It is this energy that reflects off the honeycomb that damages the back of your work and also this energy that can ignite the vapour below your cut. Yes leaving the protective film on the back of your material will stop marks on the reverse face but have you ever looked at the little nicks it makes in the edge? When you are surface engraving, there are several golden rules. First always turn your air assist to just a whisper because your do not want the jet of air to blow the VAPOUR back down on to your worksurface. Once the vapour is in the air you need a good CROSSFLOW of air to carry it harmlessly away from your work. Secondly, use the least amount of power possible to get a good image , do not try to get a deep cut. The more material you convert to vapour the more likely you are to get those "grooves" in the bottom of your cut and the white recondensed fumes all over the bottom of your cut. Experiment using the preionization zone when engraving acrylic. It works wonders. Best wishes Russ