tell me about making composites

[contero]

I've recently been interested in making things out of fiberglass or possibly graphite material. I read a pretty general explanation off of google, picked up some balsa/polyester/epoxy at a hobby shop and made a little boxed in balsa piece.

I'm interested in making larger things out of composites and I know that some of you on here do this. Can you explain some of the finer points of making things out of fiberglass? Or at the very least point me in the direction of a book/video/class where I can learn how to do it. I have a few basic questions also.

- I've only seen fiberglass made with some sort of lightweight core. It isn't neccesary to make fiberglass with a core, is it?
- If not, how do you go about giving it the right shape?
- I would imagine something like a polyurethane mold is used to do this. If so, how do you make it? Do you pour out a block of polyurethane foam and carve out a mold?
- I'm not looking to just make body parts or whatnot, but how thick are body panels/parts usually made? Something like 3 layers of fabric with 3 coats of epoxy each?
- How do you "wet out?" I've heard a couple different techniques like coating the surface with epoxy and laying the material down on that to keep bubbles from occuring.
- If you are covering a 2 sided surface with fiberglass where the ends of each side are tapered and the fiberglass will be touching, how do you lay it out? one side will have to always be facing down and both should still be wet IIRC.
- How do you mix your epoxy without making bubbles?
- Not only that, how do you keep bubbles out of the entire thing?
- What do you use to apply the epoxy?
- I've been looking at the stuff at http://www.fibreglast.com/ and I think I might order stuff from there. If there is a better site or local place (san jose) where I can get materials cheaper, please tell me.
- Last, what are some of the essential tools used to make good composites that I will probably overlook?
- Anything else I should know?

I'm not getting into this because OMG CARBON FIBER I"M GOING TO SAVE MONEY AND MAKE MY OWN CF HOOD or something. It's another skill, like welding, that I would like to have and be able to use when I need it. Thanks for your help.

[Sniper]

let's start over with all these questions.....do you want to make something one off out of glass/carbon or make something that already exsist in a different medium?

[contero]

Both/either? For simplicity's sake, let's say I wanted to make something like a door panel or a fender out of fiberglass and I have the original body part.

I don't want to be limited to just being able to reproduce things but for this thread let's just start there.

[psycheb]

I hear CF is decently easy to make? How would one go about replicating a car part in CF? make a mold out of a certain material i assume, and then.........?

[PNG]

You might want to check out www.aircraftspruce.com (and be sure to request both their big catalog and the motorsports catalog - They're free for the asking). They have all sorts of supplies for making composites, books on the subject, and even instructional videos, IIRC.

[contero]

I found a book that looks pretty good. I guess this kind of thing is too complicated to explain over the internet.

[Sniper]

quick steps for making a fender....

A.) mold making
1. cover outside with mold release
2. pour on a bunch of resin
3. lay fiberglass
4. layer it up so it won't bend all over the place and incorporate a jig around the outside
5. (not exactly needed) flip it over and do the same steps for the inside, again, making the jig so the two halves line up.....also fill any small holes with bondo/icing/etc.
B. part making
cover both halves with release
dump a bunch of resin on the outer side
lay mat(watch the grain if you're doing cf. and you care about it.)
more resin, covering all the mat
press the other side of the mold in....you should have enough resin in there that it squeezes out.
let it cure, outside side down seems to work best for me.

pop it out and show friends y0 mad skilz.

[contero]

Hey, that seems easy enough (until I actually try it and run into problems I'm sure). Thanks, that gives me the general idea I guess.