Carbon fiber people, help!, I need info Options

[Dr Evil]

I have seen some very impressive custome work on this site and the latest had me thinking. If the door panels that I have seen did not require a vac bag, how did they do it. I have worked fiber glass before, and even had access to a vac bag set up when I worked on helos, but not anymore. With the cost of carbon fiber I would like to avoid a steap learning curve, so any info on techniques, amounts and types of materials, would be greatly appreciated. How do you get the pretty finish?

[Jeroen]

For flat stuff like door panels, you can just buy sheets of carbon fiber

[Dr Evil]

Jeroen,
Ya, that part I know, but how do you cut, mold, and get the nice after finish? Luckily most of the stuff I want to do will be flat, but not all so I need to know how to do curves (door basket).
-Doc

[URY914]

You are able to sand and polish the "finished" side of c/f. If you have small imperfections after you remove it from the mold, like air bubbles, you can rough up the area, mix up some resin and fill the hole. Let it cure and hit it with some 320, 400, 600 paper, than bring out the shine with some rubbing compound.

Not a big deal, really.

Paul

[URY914]

I had several areas that needed to be filled when I made these...

[Jeroen]

Hmmm... maybe you misunderstood. The sheets I meant are already done.
You just saw them to the shape you need and bolt em up (IMG:style_emoticons/default/biggrin.gif)

If you want to make big flat sheets yourself, you can use a piece of formica (hope that's the same in English (IMG:style_emoticons/default/biggrin.gif) It's the cheap wood panels with plastic covering)
This will get you a nice smooth surface to work on and it's cheap.
Lay down a good clear gelcoat, then the carbon weave, just like you would with fiberglass
You can make it from different layers of carbon, or just use 1 layer of carbon (the one you see) and use regular fiberglass mats to build up strength/thickness or even kevlar

For curved pieces, the molding is just the same as with fiberglass, except for clear carbon, you need perfect molds and perfect first gelcoat and a nice clean layup to get a good result because all stays visible
With fiberglass, you can fill imperfections because it gets painted anyway

Disclaimer... I've never done this before, but from what I heard and read, this is how it's done...

[Dr Evil]

Jeroen,
Yup, I missed your point. That sounds very interesting. Formica is the same here, too. Thanks for the tip.
Paul,
Thanks for the info. The major differance was that you can cover fiberglass and not care so I have never pollished it.
Thanks guys!

[URY914]

I was surprized whenI polished it how well it brought out the shine.

Jeroen explained the process pretty well for flat work.

Try it on a small piece first.

(don't tell anyone, but I found almost no differance between working with c/f and f/g)

Paul

[monkeywrench]

Carbon fiber look

If you just want the carbon fiber look just lay it in like fiberglass. I have heard of cloth that is used to fake the carbon fiber look. And you can use poly-resin. Gellcoat polishes up well.

Carbon fiber structure

Laying up strong carbon fiber involves running the cloth/threads in a direction that is needed. This is done by various crisscross of the cloth or knowing where the force is needed. Air bubbles in the epoxy cause a major weak point thus the need to force the air out by vacume baging or other compression.

So what are you thinking of building??

[SpecialK]

If/when you're drilling holes in CF you'll be needing carbide "dagger/spade" drills for the smaller holes (less than 1/4"), and diamond impregnated hole cutters for the larger ones. Diamond impregnated and carbide cutting or drilling tools are a must because real CF eats high-carbon or any other drill bits for breakfast!


Dagger Drills:

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...sspagename=WDVW

I've worked with CF for a loooong time, but mainly structural repairs that didn't require them to be aesthetically pleasing (plane's getting painted anyway). Vacuum bagging and heat curing a part (with the correct breather and bleeder layers) ensures an optimal CF to resin ratio for strength and stiffness, but that's not important if they're non structural or decorative parts like door panels or lense covers. If the parts are to be molded, and the mold is fairly intricate, vacuum bagging would help to eliminate possible air pockets from forming in the tight corners.

As for composite parts fabrication, Morph is the man to talk to for "tips/tricks", high quality stuff from what I saw.