How to create mold to copy existing items?

[Jakobud]

For a project, I have some aluminum cylindrical tubes, roughly 2" in diameter and 10" long.

I'm toying with the idea of replacing the tubes with home-made carbon fiber tubes. Even though I'm new to working with carbon fiber I should be able to figure that stuff out.

The problem that I'm trying to figure out though, is how to make a mold to properly make carbon fiber tubes that are "exactly" the same dimensions as my existing alum tubes?

I need the carbon fiber tubes to be the same length, same inner and outer diameter.

Carbon fiber typically has to be wrapped around a mold. But in this case, the mold to wrap around would have to be equal diameter to the inner diameter of the existing tubes. Wrap carbon fiber around it enough times and I'll get a carbon fiber tube with the same inner and outer diameters as the existing tube.

Does that make sense? Where do I begin? Anyone point me in the right direction?

[SORCHEROR]

not sure but i dont think carbon fiber will shrink much,so the core on the mold would be about the ID of your tube,the OD you will make the the mold same as the tubes OD
and wrap just enough fiber around the tube and stick it into the mold and sqeeze the whole thing together,carbon fiber is compressed during the curing process,most likely you will have to make the lenght longer and machine that fnish after,i dont think it will come out that good other wise

[Jakobud]

What should I make the inner tube mold out of? Wood? Metal? Something else? I'm afraid that the epoxy/resin used with the carbon fiber is going to make the carbon fiber tube permanent stick to the inner tube mold after its dried.

[awerby]

wrap the core with waxed paper, so that nothing sticks. But are you sure you can't just buy graphite-fiber reinforced plastic tubes the right size? That would certainly be easier than trying to make your own (if not cheaper - this stuff's expensive!: Large Carbon Fiber Tubes )

But if you're set on doing it yourself, here's some step-by-step guidance, with pictures:

Making graphite tubing

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[Jakobud]

Thanks for the direction. I've already got a big roll of carbon fiber cloth, so it will definitely be cheaper to make the tubes than to buy premade ones. And I'd like to learn how to work with carbon fiber as well, so it will be fun to do as well.

[SORCHEROR]

they usually clamp it under high pressure and heat it too cure it,makes it stronger,not sure what your using them for,make the mold out of aluminum and spray it with a release agent or cooking spray