EPP and Kevlar Drone Construction Techniques

Want a bulletproof drone? This is a start....
Over the years I have sourced all my Kevlar from sweetcomposites.com/
They are not paying me anything to say that and that is not an affiliate link, that is just how much I love them :).
Some videos showing these planes in action (most of the videos are not mine):
• We're Back! Chimera vs...
• COFPV | Drak V. Grauga...
• COFPV | Moab, Utah Pt. 2
• COFPV - Drak chasing G...
• COFPV Hartsel Meet | 3...
• Twilight Canyon Cruise
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[@AdrianMelia-0]

I love your tidy, organised workspace!

[@talisman3d595]

Thanks for making these videos. This is exactly what I want to be doing

[@blissbouwerij4033]

Great video and technique, Thanks

[@PKsLab]

Awesome stuff! Thanks for sharing!

[@thinkflight]

You bet!

[@daemn42]

Very cool. All my favorite materials in one vid.. Kevlar cut on the bias, thinned Goop, and thin CA. I never cared much for the way spackling is used to fill in the wire cut EPP surface in traditional PSS construction because it'll de-bond from the foam on impact or sharp bend and then can never be repaired without stripping *all* the covering off. But bonding it with thinned Goop makes it permanent. . I can attest to the durability as both the planes I fly that you built, have taken some pretty serious hits and have never delamed. I've creased the surface here and there and broken a joiner, but that's about it. Didn't know that about n-propyl acetate to thin Goop. Wonder if that's available in countries that don't have access to either Toluene or Xylene Perchloroethylene (aka perc, aka dry cleaning fluid) will also thin Goop. I've always used 3M Super 77 misted directly onto the Kevlar itself rather than the surface. Same benefits as your 3M 90. Can stick it down, smooth it out, shift it around as necessary. Not as thick and gooey as 3M 90 and won't ever obstruct the pores of the Kevlar fiber from receiving thinned Goop or CA. Best to do it outside and downwind though as the mist will get on everything nearby. Easiest way to not cover your fingers in CA (or glue them to the surface if/when it kicks fast) is to just cut off a short length of good clear packing tape, stick it to your fingers, and then rub the CA with the slick side of the tape. Can even hit the CA with a little kicker at the end to firm it up and still rub it down (which you'd never do with your bare finger). And maybe the blue CA doesn't fume as much but my Zap brand thin CA (I buy it in big 2oz bottles) is really obnoxious and it requires a lot of ventillation or it will burn your eyes/throat.. etc.. I apply it outside if at all possible. Inside with a fan otherwise. Any pair of decent kitchen scissors can be turned into quite effective Kelvar shears if you've got a bench grinder in seconds as I demonstrate here. kzbin.info/www/bejne/qHiZi3l3aplmeKs You can fill in the pores and make Kevlar a little bit sandable with the same thin CA trick you're using on the TE. Oh, and you might want to throw this up in the Slope forum as it really is highly suited to EPP PSS construction. A brand new EPP PSS plane can be every bit as smooth and fast as a wood/glass one but the complaint is always that after a couple hits they start to get pretty ratty, due to a combination of torn cloth (folks used to use Solartex to wrap the curves) and the aforementioned spackle fill layer failing.

[@thinkflight]

Thank you for stress testing and flying these planes to their maximum over the years. Appreciate the recommendations and details above.

[@nevillecreativitymentor]

I saw your Kevlar Scissor hack of the decade video ... AWESOME

[@austntexan]

You really cracked the code with that spackling witches brew. I'm using it on a build and it's incredibly forgiving and clings to the EPP like Grim Death. I see what you mean on the EPP density(RCG comments). The whole process works best with #1.9. I'm doing a VAS build and I think he cuts his wings out of #1.3. It's not impossible, but I'm sure it sands easier/smoother with #1.9. Well done and thanks for sharing these fantastic techniques.

[@IlusysSystems]

I developed similar coating technique, but I am using PVA glue and non-woven textile from gardening supplies for very light planes. Sticks very well to polystyrene, haven't tried to EPP. But it is water soluble, which may be an issue sometimes.

[@superbeetlejosh]

are you talking about "geo-textile" weed barrier? That would be a lot tougher than fiberglass.

[@IlusysSystems]

@@superbeetlejosh not quite its thin 50g/m2 stuff from gardening supplies. Not sure what it is used for.

[@BigAlNaAlba]

Interesting, do you have any construction pictures of your technique?

[@IlusysSystems]

@@BigAlNaAlba Sure here you go: kzbin.info/www/bejne/r5CUfZeDaNFpY80 Hope, that links are allowed

[@BigAlNaAlba]

@@IlusysSystems Thanks for sharing. Your video is really worth a look. :)

[@frasersteen]

I attempted a version of this a few months ago. I thought I was crazy. Nice to know I wasn't and to have some advice to make it better. I tried it with fibreglass and it worked but arguably not much better than laminate or tape.

[@carmeloarroyo5520]

i'm deff going to try this on one of my mini draks.

[@memo73219]

Thank you for sharing these great techniques! What kind/weight of kevlar do you use?

[@JNacoustic]

Awesome thank you for sharing. I know you were kind of keeping this under wraps for a while.

[@thinkflight]

I would have shared the idea immediately after learning that patenting it probably wouldn't be worth my time, for whatever reason that never occurred to me. Better late than never.

[@parshvapatel8484]

Think Flight It would be a great video if you build something similar to this kzbin.info/www/bejne/fWnNgnafrrmNfrM Also, what should I study if I want to make VTOL and large scale drones , wasted a month but found nothing

[@AntiVaganza]

@@thinkflight Just curious, did you seriously consider patenting this or were you joking?

[@waynep343]

Hint. See if you have a Re-Store and look for a kitchen range hood to install over your work area to allow the fans in the range hood using aluminum ducting not vinyl. To pull the xylene , toluene and CA fumes out of your work area . Even with a respirator you dont want to be breathing them.

[@robertfpv7733]

Nice strix hat is was thinking of getting one when I bought my nano goblin but forgot lol its discontinued now lol

[@guillermocortes3783]

Totally off topic, but where do you film your flights. Love the scenery.

[@charlespolk5221]

I wonder if you could use a similar technique used by boat builders to cover in kevlar. Apply kevlar and goop, then put polyester release cloth over the laminate and put the whole thing in a special vacuum bag and apply a vacuum. Remove from the bag and peel off the release cloth to remove the excess goop and get the kevlar weight to goop weight as close to a 1:1 ratio as possible. That gives the best weight to strength ratio. Note that boat builders use epoxy resins to accomplish this technique when building foam core boats. I don't know if the foam used in boat construction is similar to that used for prototyping aircraft or not, so the foam might not be compatible with the epoxy.

[@pangrac1]

To fill the voids you can use epoxy with microballons too and is less toxic I guess. But I always use mask with charcoal filters with epoxy.

[@migalito1955]

I wonder if sealing the wood with shellac & or using a grain filler would allow your mixture to bond the Kevlar to the wood?

[@k.bellingham8335]

Recently discovered your channel, very cool stuff happening here! Interesting techniques and material choices too! Question; "Laminates", you use this term to describe what exactly? Laminates can be sooo many different materials, to what are you referring when you say "I use kevlar instead of laminate"? "because of weight,, strength, durability etc." Good flying, or would good ground effecting be more appropriate, regardless, can hardly wait to see your ship take to the air.

[@bbrockert]

Googling around it seems that it's just called laminate film, used as a skin layer over foam airplanes. No one says what plastic it actually is.

[@diveflyfish]

Thank you for sharing this technique. Just out of curiosity, I noted at minute 6:20 in the background,( this is a long shot question,) Is the green book, a Frank Netter Anatomy Volume? Just curious. If so, I too have that set. It is a great. Have a great week. Thank you again. Very Best Regards.

[@thinkflight]

Unbelievable, yes it is.

[@diveflyfish]

@@thinkflight super! Wonderful distillation of information. He was a genius at combining a wide array of material in a manner that is visually memorable. I used them during my schooling 26-30 years ago! Thank you for your confirmation.

[@bluecookiemonster3]

clicked on the ArduPilot yaw wag video, Now I want More EPP wing content!!! I have 3 of Reubens wings from Sweepwings and I know he cut his from EPP in his workshop and ever since I built those and they were a freaking blast (and indestructible if laminated properly). I Gotta get to making a setup to do this once Summer starts. Never thought about Kevlar but Im down considering how impossible it would be to break. I have a Strix Stratosurfer I was going to make a Twin setup and printed the motor mounts last night. Now I want to Kevlar the Wing before I do that so it will last forever but would this process be safe for EPO foams? Thank you!

[@thinkflight]

It is not safe on EPO, but you can use polyurethane glues or something similar that will not attack the foam. For EPO I would generally stick with laminate, as the flexible kevlar application is better matched with EPP characteristics of deformation recovery than EPO. Good luck and experiment!

[@kiranpande5416]

Hey, found this vid very insightful, could you please tell me how to go about doing the same using carbon fiber/glass fiber/kevlar in an Autoclave machine? and is it really advisable... please give your thoughts and info, thanks!

[@timschmitz9581]

can you use the goop technic also with carbon fiber?

[@latexrope1358]

You don't wear a respirator when applying the cyanoacrylate?

[@siop5709]

Can that goop and Xylene mixture be used to apply carbon fiber?

[@chrisw1462]

Didn't really say the proportion of Toluene in the mix. I've noticed in a few of your vids you tend to explain in depth what you're going to do, then do a montage / time-lapse to actually do it. Explaining with a voice-over _during_ the time-lapse would make a much better video.

[@tombouie]

Thks but ??hows-abouts the advantages & disadvantages of 3D printing a RC airplane??

[@PrefersAnonymity]

Love the channel and the help your giving. Question: Is thinned epoxy too heavy for these kind of builds? or is there another reason to not use it? Also as a filler, thinned epoxy with micro balloons for the foam? It would obviously add strength and adhere to your trailing edges without the need to use the CA? Thank you. I apologize if this sounds rediculous but trying to rationalize the build after a few decades away. 😤

[@thinkflight]

A mismatch in material properties. Going for flexibility, not rigidity. Want everything to bend and not break in a crash.

[@PrefersAnonymity]

@@thinkflight Thank you

[@donochetti2177]

Hi, can you tell me what plane that is in the beginning of the video @ 0:02 , thank you so much. Enjoyed the video!

[@thinkflight]

kzbin.info/www/bejne/jXnNfWtmrqiDqcU

[@tom1907]

Is this the plane you designed？

[@GOAFPilotChannel]

why do you use goop over laminating resin?

[@212caboose]

What about using gesso? It's basically a paintable spackling? Also, why thinned out goop, rather than epoxy? Is it a weight thing?

[@thinkflight]

In my experience gesso is very heavy and dense. The goop is about flexibility, epoxy is very stiff. Depends on if you want a durable airframe or not.

[@Mike-oz4cv]

Is the respirator really going to help against toxic gasses? I’d assume that a well ventilated desk (maybe with a fume hood) is more important. And why are you not wearing it while sanding?

[@ericliu2727]

If the respirator filter cartridges have carbon in them, they can indeed do a good job against toxic fumes.

[@zakiabdinasiromar5434]

Can I use the kevlar ontop of balsa skin?

[@zakiabdinasiromar5434]

Can i use kevlar over a nylon 12 printed airframe?

[@Allan_aka_RocKITEman]

👍👍

[@haraldschurr1035]

@Think Flight: wouldn't it be much healthier to wear a breathing mask while sanding fiberglass - too?

[@jeffcauhape6880]

What kind of foam do you use for the core of the wing?

[@thinkflight]

EPP

[@mithrandir1313]

I have had some luck wet sanding kevlar with finer grits of sandpaper...

[@janspoelstra8309]

Is the Kevlar plain woven, or twill woven? I'm having a hard time finding Kevlar/Aramide that thin (1,7 oz/m²) 'locally'.

[@thinkflight]

Plain weave

[@janspoelstra8309]

@@thinkflight Thank you, that explains the somewhat wastfull cutting it to the bias. I ordered some Aramide cloth from China to see how I like working with it compared to glasscloth and epoxy.

[@elbowdonkey]

I suspect the balsa quickly soaks up the Xylene/goop mixture, preventing a good bond between the Kevlar and balsa. If you sprayed a primer on the balsa you might have better results (as long as the Xylene doesn't melt the primer). An alternative to using a primer is to use a mixture of epoxy and micro-beads. The micro-beads (just super small, powder sized glass bubbles) fill in the wood grain and reduce the weight of the epoxy coating while still being really strong and sandable. If it were me, I'd do whatever I could to avoid spreading thin CA with my finger. I've been literally burned by CA as it set off, which is worth avoiding. It's great stuff, but I just don't trust it. It acts differently depending on the humidity levels, the brand you buy, how old it is, etc. Using epoxy to bond the Kevlar to the balsa might be just as durable, goes on quicker and more consistently, and is a lot lighter than CA.

[@thinkflight]

I don't have any microbeads on hand but it seems logical, I'll order some and give it a try.

[@elbowdonkey]

@@thinkflight You can also use balsa sawdust instead of micro-beads. Or just skip the micro-beads and aim for a thinner coat of epoxy for less weight. Though I suspect if you're covering with Kevlar, weight isn't so much a concern.

[@thinkflight]

@@elbowdonkey Yeah I don't think a thin layer of epoxy would hurt anything at the weight and size these already are. Need to try this out.

[@markgerard363]

OK.... that was a real surprise to see that you don't use any kind of resin... I mean from the perspective of repair it have to be like living in heaven it self.. some more goop and the heat gun and it have to be like if that crash never actually happened.... but let us talk about using resin " The rigidity and the extra strength that is offered by the composite are a force to be recon?? ?don't you agree?? the rest well you have actually take me to school!! you have leave a ton of brand new knowledge! thank you very much for your videos....

[@thinkflight]

The extra strength and rigidity offered by resin impregnated composites is indeed necessary for many types of builds. You must select your construction technique for the benefits offered in each use case.

[@markgerard363]

@@thinkflight I do believe I will keep using the regular polyester resin for the leading edge only... but definitely will give a try to that goop/Xylene recipe of yours.... may I ask you where do you buy the Kevlar???

[@thinkflight]

@@markgerard363 SweetComposites

[@markgerard363]

@@thinkflight Thank you very much! I really appreciate your time...

[@roidroid]

1:09 What does "Laminate" mean here? He's using "Kevlar instead of Laminate", *what is "Laminate"?* (it has so many meanings, it's not obvious)

[@thomasmaclean7465]

Why thinned Goop and not Epoxy?

[@thomasmaclean7465]

Found my answer below, Goop will flex in a crash.

[@Dreamer66617]

ventilator, but no gloves!!!