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DIY Composite tubes?

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ttabbal

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I've been looking around for some info and found a few tidbits, but didn't see a thread dedicated to the art of composite tube making. I was wondering if some of the pros would be willing to share some info. I'd love to start making some small diameter tubes, say 38mm and under. I've had some success glassing cardboard tubes, but I'd really like to try full FG and CF layups. My plan is to start with materials I already have, CF cloth and Aeropoxy laminating resin. I know I'll need mold release, any tips there? How about mandrels that are close to the right diameter? It looks like 3/4" copper pipe is pretty close to 24mm, for example.

Another option that comes to mind is dissolvable mandrels. Perhaps 3D print in PVA, then use water to dissolve the mandrel out. ABS dissolves in acetone, though I'm not sure how well epoxy holds up to acetone.
 

ttabbal

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Thanks for the info. I tried searching for Jim Jarvis, but got a lot of unrelated stuff from Google.
 

watheyak

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Mannixfan posted the link to the Jim Jarvis PDF in post 2. It's a great write up.
 

TopRamen

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This^^
Tfish knows his stuff better than most and even took some time to privately converse with me and teach me about stuff like "Peel-ply".
I've been working composites for maybe a little over a year now, but his guidance and guidance from folks here have made me fairly successful at it. I'm super exhausted right now, and am only at the computer because I cannot physically lie down, but I'll subscribe to this thread, then maybe PM you tomorrow when I'm in a better way to tell you who else you can trust when it comes to making some tubes or what ever you want to make. I've started to be confident enough to make my own mandrels from spent motor casings glued together, the made to exact dimension with Teflon tape, but have had many pitfalls along the way, so if you want to talk mandrels, hit me up in PM, and if I don't know the answers, I'll suggest folks who do.
We all begin somewhere, then find the mediums that we love to work in. Feel free to ask me about stuff like lightweight cloth, removing glassine and how much weight that gets rid of, and where to ask about more advanced things, as I can refer you to folks that know way better than me. I love composites!!!
https://www.youtube.com/user/tfish38/videos

The couple on tubing are a page down I believe.

[video=youtube;q3wtcNTd9wg]https://www.youtube.com/watch?v=q3wtcNTd9wg[/video]
 

ttabbal

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Thanks again for the posts! I hadn't considered making mandrels from spent motors, though it makes sense when you mention it. It would make for a good ID match for motor mounts and minimum diameter tubes. I'm reading the Jim Jarvis PDF and will watch the tfish videos before I ask more specific questions. No point in going over things that are covered already. I just wanted to thank everyone that chimed in. I'd love to keep it going and try to collect some knowledge here so everyone can benefit. I'll be gathering materials and posting some results as I go, hopefully we can get a few new builders going.
 

ttabbal

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I have been using aluminum tubing from DX Engineering as a mandrel and Frekote 700 as a mold release. Works great.

https://www.dxengineering.com/search/part-type/aluminum-tubing?tw=alumin&sw=Aluminum Tubing
http://www.acpsales.com/Frekote-Mold-Release.html

Jim's method linked above works great as well.

Just coat the mandrel and do the layup? Sounds almost too easy. :) It seems like a good option for the smaller tubes I want to start with though. Anything to watch out for going this route?

I read Jim's guide, loads of good info in there, and the final product looks amazing. If I manage to get half as good, I'll be thrilled.
 

watheyak

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Just coat the mandrel and do the layup? Sounds almost too easy. :) It seems like a good option for the smaller tubes I want to start with though. Anything to watch out for going this route?

I read Jim's guide, loads of good info in there, and the final product looks amazing. If I manage to get half as good, I'll be thrilled.
It took me many years to try it because I thought it sounded too easy. I just spray it on and wipe it with a microfiber towel that has also been soaked a bit with the spray. Let it dry and repeat 3 or 4 times until is "feels right". Nothing will stick to it, not tape, not epoxy.

Once the tube is cured I put it in the freezer for about 30 minutes and it pops right out. Silly easy.

Tfish and Jim's method also work great and I used that method for many years. Jim's final product really is amazing, and if you follow his directions it's very possible to get close. His finishing method is the best I've found for getting the super smooth, natural carbon finish that everyone loves. The only reason I moved on was that it was very difficult to remove the tube if you compress the lay-up in any way.

Here's some pics of a coupler tube I did recently with the Frekote and heat shrink from Soller Composites for compression.

20160806_155821.jpg20160806_160237.jpg20160806_160806.jpg20160806_170146.jpg20160806_170719.jpg20160807_155126.jpg20160807_155246.jpg

Here's a link to the Soller heat shrink tubing if you want to compress the lay-up. It's not necessary, but it makes for a dense layup with very little surface finishing required.
http://www.sollercomposites.com/composites/carbon fiber sleeves.html#Shrink
 

JimJarvis50

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Just coat the mandrel and do the layup? Sounds almost too easy. :) It seems like a good option for the smaller tubes I want to start with though. Anything to watch out for going this route?

I read Jim's guide, loads of good info in there, and the final product looks amazing. If I manage to get half as good, I'll be thrilled.
Thanks! There's a Part 2 article here. It's a bit closer to what I do now.

Jim

http://www.raketenmodellbau.org/repository/archive/167793?view=true
 

ttabbal

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It took me many years to try it because I thought it sounded too easy. I just spray it on and wipe it with a microfiber towel that has also been soaked a bit with the spray. Let it dry and repeat 3 or 4 times until is "feels right". Nothing will stick to it, not tape, not epoxy.

Once the tube is cured I put it in the freezer for about 30 minutes and it pops right out. Silly easy.

Tfish and Jim's method also work great and I used that method for many years. Jim's final product really is amazing, and if you follow his directions it's very possible to get close. His finishing method is the best I've found for getting the super smooth, natural carbon finish that everyone loves. The only reason I moved on was that it was very difficult to remove the tube if you compress the lay-up in any way.

Here's some pics of a coupler tube I did recently with the Frekote and heat shrink from Soller Composites for compression.


Here's a link to the Soller heat shrink tubing if you want to compress the lay-up. It's not necessary, but it makes for a dense layup with very little surface finishing required.
http://www.sollercomposites.com/composites/carbon fiber sleeves.html#Shrink

I had wondered about compression. My first thought was vacuum bagging, but that seemed like it might be difficult with a tube. I wouldn't have thought about heat shrink though. Interesting idea.

They had a video using a carbon sock over the mandrel. Is that method less desirable or just more expensive?
 

watheyak

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I had wondered about compression. My first thought was vacuum bagging, but that seemed like it might be difficult with a tube. I wouldn't have thought about heat shrink though. Interesting idea.

They had a video using a carbon sock over the mandrel. Is that method less desirable or just more expensive?
I've used carbon sleeves a bunch for R/C sailplane fuselages. They're kind of a pain but great for a taper like a tailboom. It's also very difficult to get multiple layers of sleeve on the mandrel in an orderly manner while the resin is wet. You'll always mess up the underlying layer due to the Chinese finger trick behavior of the sleeve. They're also not the ideal fiber orientation for a rocket tube. In the end, rolling fabric on the mandrel is easier, if not more time consuming.
 

TopRamen

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This is a video about CF Tube making that I've watched three times now, and it has a fair amount of detail that are worth trying to keep in mind.
It's 49 minutes, but a worthwhile 49 minutes.
I like that they touch on epoxy safety, as I am sensitive to epoxies having used them frequently in a past job, (96'-02'), but without the proper knowledge or safety gear.

Enjoy, more than once even!

[video=youtube;TwfyvkGAPjQ]https://www.youtube.com/watch?v=TwfyvkGAPjQ[/video]


I'm still very new to making tubes from entirely CF, so I spend whatever time I can doing research, as CF is too expensive to waste if I make mistakes. I am still working with my first yard that was generously given to me by a member here.
I have made a 13mm all cf tube and rocket, and a 24mm tube which has not become a full rocket yet, but was made on a mandrel but around a paper body tube that had the glassine layer peeled off. The mandrel was made using spent D motors, and I used my digital calipers and some fine tuning with CA and primer to make it serviceable tolerance wise.

I tried to wet it with water for the pic, so that's not delamination, the dark/light spot are just the water evaporated away before I could take the pic.
Star Trooper CF24 Mandrel 2016-05-23 001.jpg24mm CF Star Trooper and Deer 2016-06-10 012.jpg
 
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