composite materials and pvc forms

[cattlehound]

having done several hours reading and researching I have some idea of what I want do. I would like to form 2 identical 6' long, 2" OD (roughly) tubes out of Carbon Fiber (with an arcing profile). after toying with some ideas I thought...

Using PVC bent under load, lay up a glass sock or sleeve over the top (applying pressure with heat shrink tubing?)... wait for an intermediate cure.

Carefully cut the glass fiber away from the pvc and use this as a form for laying up carbon fiber (as per my requirements, not important for this post)

Question, would a vacuum and or heat shrink cause the glass (at only 1 ply thick) to implode / crack / deform, under the carbon fiber layers? Is this a terrible idea, ie would the thickness of glass required to hold up to vacuum negate the weight loss of using carbon all together?

further thought... joining two or more curves made this way, with straight tube and or what ever you might need, at the glass stage could produce a very clean, tidy form for CF tubes (depending on all the applicable strand orientation / epoxy / thickness variables)

Any thoughts greatly appreciated...

[Mr Efficiency]

I'm stuck on understanding what this vacuum stuff is all about, in fact I have " NFI " !

[cattlehound]

sorry, long day at work.

having formed a fiber glass tube with the bend I need, I could vaccum form layers of CF over the top (or use heat shrink tubing to compress the composite-resin matrix to remove excess epoxy).

If that makes sense... Imagine two or more curved tubes of glass sleeve joined, then vacuum form a nice, smooth, consistent double curve carbon fiber laminate tube

[Herman]

If you don't envelop the whole structure in a bag, you could get away with it. However, keep in mind that 1 layer of cloth very likely is not vacuum tight.

[rwatson]

How are you going to 'carefully cut the glass layer away from the PVC" ?

The bond is really good - it would be a case of grinding it away.

What would be the problem with just hand laying the glass over the PVC for your 'former' ?