The 1st , Ive ever heard of pre-peg and infusion was from this forum.
I can see the benefits of prepeg doing these tubes and I think the heat box will get to 250-275degrees as it is. Worries me when it gets this hot though.
Eventually Ill try both these systems but I have an inventory of regular carbon and materials I bought from another hobbiest. I am going to have to work with the materials I have for a while.
Tips off this forum have really helped me and Im getting close to being able to make the quality of product Im shooting for
Thabks again
What I want to do is keep the 1st edge tight in place so I can really do a tight wrap as I go doing the layup.
I just finished a little test with a clear surface coat epoxy.
The stuff gets tacky in 1 hour. This should work good.
Sorry men if I am revisiting things that have been posted before. I do try to hunt the forum before asking my goofy questions.
Thanks again
Cant say I aint been trying.
Atually these tubes are all in good shape . Usable.
Out of all my experiments I think I have only had to throw 2 in the garbage.
I like working with this stuff but I have one big problem that may shut me down.Im allergic to either the epoxy or hardener . Itch myself raw at night. Starts looking like poison ivy. This is screwing me up bad.
wear protective jackets and gloves when handling and cutting the fiber!!! Don’t dismiss the fibers giving you a hell of a time…even if you cut the fiber with a knife, it can throw off a dust of fine microscopic darts. They will enter the skin and cause a rash like problem. I’m not discounting the resin, but people forget about the fabric! Just wear some Tyvek lab coats. They are cheap, and might be able to be washed if careful. Gloves are mostly important no matter what!
The tubes look great. I think once you get your process down it should work fine. Just messy!
Do you hand roll the tubes and tape, or have the mandrel on a motor and put tension on the material? The FG antennas my last job made, had a pressure roller system to roll the prepreg, and then a tensioner on the shrink tape to tightly compact the tape before cooking it. Just makes it easier than doing it by hand 
I havent been protecting myself handling raw fabric. Today the itch is playing hell with me and I havent touch any resin. But I did mess with fabric . Ill heed to your advice on this (gloves, Jacket). It would be great if it was the material itself screwing with me. That can be fixed.
These tubes are hand layed up over an aluminum mandrel, all by hand.Ive been daydreaming of some backyard electric tension set up. Even if it was just a motor that turned the mandrel by touching a foot pedeal or something.
Is there a chance you no of a pic or two of a machine that does these procedures. Today I talked to a person that mass produces parts for our hobby. I believe his machine is pretty much fully automated, Does the layup and then puts on a material called BOP(if I have it right)over the layup.Im wondering what this machine looks like.Just curious how its done commercially , I realize this guy has a serious investment in equiptment
For some tube making methods, commercially it works exactly the opposite of what you describe.
Good that you will start protecting yourself from the fibers. Long sleeves and gloves should always be the norm.
The resin also can build up an allergy. Your body can only take so much…and when you get to your personal limit you will have developed a sensitivity…then you will have trouble working with it again.
I myself am also higly allergic to some epoxies, it sucks to have your hands swell and turn red for many days. my first suggestion for you is to find an epoxy that you are not sensitised to. there are many epoxies that dont bother me at all. tooling epoxy is the worst for me. I always wear nitro powder free gloves then put latex on top of that and change them out often. also where a vapor resperator as even the fumes you breath can cause allergic reaction on your hands and wrist. ultimatly I think you going prepreg would be the best for your tubes. they will stick well to your tubes and it will be hard for you to have an allergic reaction to it since the resin is not in a fluid state. your tubes will be lighter stronger and very consistant.
“exactly the opposite”.
That doesnt suprise me in the least.
Im pretty sure the sesetivity limit has already been reached. I ended up in ER a week ago the hives were so bad.Told the wife I will probably have to give it up as soon as I start having fun.
Thank you men
I should have explained “opposite” better.
Instead of taking the fabric and trying to wind it on the mandrel (it would seem difficult to keep tension on it without distorting the fabric)…think about a different approach.
What I have seen is fabric laid out on a table. The fabric doesn’t move, the mandrel moves over the fabric. It rolls out over the fabric with pressure winding the fabric up as it moves along. If you have a layup schedule that varies you can easily lay all the plies out the way you want the finished tube to end up.
You still have the same problem getting the first edge attached, but otherwise it is a great way to get the fabric very tight on the mandrel. That is where prepreg comes in.
Tbone: no, sorry, no pictures exist. It was like a lathe, where the mandrel was attached. Parallel to that were 2 other rollers, that I think clamped down onto the mandrel, and compressed the fabric as it was layed on, and rolled up. Almost like some candy machines that pull and rotate the sugar. (i watch lots of Unwrapped)
dy123: Yes, I have done that with my prepreg, to compress the fabric as I roll it. Takes a steady hand, but it works.
Glad you guys dont think Im obsessed with this tube stuff LOL Iam.
Dy123
Ill for sure study up and test out pre peg as soon as I get back to work.
I have 25-30 yards of 8.3oz twill fabric to practice with in the mean time.
riff42
Thanks for the description. I can see it in my head.
Both
I just spent a couple hours rigging up an adjustible tensioner thingy on the dispenser roll and the mandrel. I actually think this may help.:rolleyes:
Hi,
this is how I make my tubes. maybe it will help.
I place the outer layer down first on a glass plate and wet it out. The I add the next, wet it out, and so on. When I have it all layed down I slightly lift the leading edge and place an “L” shaped aluminum straight edge underneath with the long arm pointing to the edge of the carbon. Leave about 0.5 cm looking past the al piece. Place the mandrel on that and start rolling. As soon as the edge starts to go under pull the al part off and continue rolling without it. If I need a little more tension, I use the al part to clamp the carbon to the mandrel for each 1/4 turn. That way I can pull back on the mandrel while I roll. I’ll try and post some pictures when I make the next ones but that might be awhile.
Cheers
DB
Great!
Lets see the pics when you have a chance
Terry
Hey, how do you do your fins? VARTM, wet and bag, wet and press, etc?
If you mean me and this picture, those are pairs of tubes woven around a mandrel. The idea is to increase torsional strength without going oversized or adding material. It’s wet layup in a vacuum. The single pair is for chainstays and seatstays. The double pair is a toptube. These particular ones had the vacuum fail but were still good enough for destructive testing.
The frame was not intended to look good. I wanted to test the principal. I ride it regularly and it is still holding up fine.
Cheers
DB
Um. Fins, not tubes. I meant Tbone’s rocket fins.
ps: I like the aramid braid on the top tube. Looks nice!
doesn’t anyone buy tubes? I’ve never made a tube. There is a winding factory nearby, and I don’t think I can make tubes as stiff, light, and cheap as they can in their mass production
ok, they dont have the twill fabric look, wich is nice on homemade tubes 
i had some from an old project awhile back. But no, you can’t make it as good as the professional tube makers do…but you can’t also PAY for them
I lay them up wet on either glass or aluminum . Then put a top piece on. Then put it under vacuum.
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Have you played with foam cores at all? You would get a lighter fin. Of course, much of the design would involve knowing how much pressure they take, especially the leading edge.