Carbon Fiber, Specifications? Options

[Todd Enlund]

I want to make a few Carbon Fiber parts for my car... but I'm trying to decide on which fabric to purchase. Twill vs plain weave, weight, and tow size. I will be using the CF primarily for it's cosmetic value, so appearance is my primary concern. I believe that twill is my choice for weave, and I'd prefer as light a weight as possible... but I'm not sure what "tow size" is. I'm guessing that it has something to do with the size of the weave, and the heavier the cloth, the larger the tow. For example, 5.7oz cloth has a 3K tow, and 11oz cloth has a 6K tow. 5.7oz would be my preference, but I'm concerned that the weave may be smaller than I want as far as appearance goes, and I may be better off with 11oz.

Anyone have any experience, and can offer some advice?

I plan on vacuum bagging with epoxy resin.

[sww914]

If it's the appearance that you're primarily concerned with, get the one that looks good. Either will be really strong.
I bought a bunch of epoxy from these guys several years ago for a boat project- http://www.raka.com/
They were far and away the cheapest at that time, like 1/4th the price of West System epoxy. I don't know how they compare now, I haven't shopped for any lately.

[Todd Enlund]

If it's the appearance that you're primarily concerned with, get the one that looks good.

That's the problem, I can't see them in person, so I don't know what size the weave is... (IMG:style_emoticons/default/biggrin.gif)

[sww914]

You need more than one layer, buy some of each and put the one that you like on the outside.

[Sleepin]

Here are some fine examples of carbon fiber weave types.

[Todd Enlund]

Here are some fine examples of carbon fiber weave types.

Thanks, I'm familiar with the different weaves, but what this site tells me is that all they offer is 3K, so that makes me believe that it is the most popular. They also sell samples, so I might order a couple to compare.

I've considered the carbon/kevlar fabric as well... U.S. Composites has it in black/orange, which might work on my tangerine car...

[Sleepin]

I looked into tow strength. Most everything I read is either vague, or way above my head. What I gather is that it measures the tensile strength.

I can't remember who, but I remember seeing carbon weaved with titanium wires. Not much for weight savings, but it looked pretty cool!

[Wilhelm]

If it's the appearance that you're primarily concerned with, get the one that looks good.

That's the problem, I can't see them in person, so I don't know what size the weave is... (IMG:style_emoticons/default/biggrin.gif)

Looks like you live in Boring,OR. Next time you are in PDX go to TAP Plastics http://www.tapplastics.com/shop/locations.php?lid=3 and you can see some carbon fiber.

[dw914er]

go with the double weave thing. Buddy has it for his hood on his 350z, and it looks good, with better depth than the single weave.

[hcdmueller]

Find some carbon fibre with metal filament woven in. It has some interesting properties concerning radar signature....

But you are probably just making smaller parts.

[r_towle]

Where are you getting the supplies?

Rich

[Todd Enlund]

Where are you getting the supplies?

Rich

Best prices and selection that I have found is U.S. Composites.

[Grngoat]

3K, 6K, whatever refers to the number of individual fibers in each tow. So 3K tows will be half the size of 6K tows, resulting in a finer grid. You probably want something larger if you want to see the weave from some distance away. Plain weave is what you normally see on automotive stuff, so it's what people "think" carbon fiber looks like. But 5HS is stronger and more typically used on real structural parts. Strength wouldn't matter in your application though.

[jd74914]

Here are some fine examples of carbon fiber weave types.

Thanks, I'm familiar with the different weaves, but what this site tells me is that all they offer is 3K, so that makes me believe that it is the most popular. They also sell samples, so I might order a couple to compare.

I've considered the carbon/kevlar fabric as well... U.S. Composites has it in black/orange, which might work on my tangerine car...

Watch out for Kevlar, you might have to deal with fuzzies if you go that route and they are supposed to be nasty (at least that's what I've heard from some composites engineers at PWC).

[charliew]

The cost of carbon along with it's availability has really gone up and will stay costly because of the military consumption. My son has a CF hood with some damage to the edge and I still haven't figgured out how to fix it without painting over the repair. I have bought fg supplies from Fiberglast and they are very helpful with advice on most applications.
I ran across a supercar made out of wood composites and they had several ideas on vaccuming composites. It's a college project and if you've got time it's worth checking out. They have a very high tech car going. http://www.joeharmondesign.com/index.html

[Todd Enlund]

3K, 6K, whatever refers to the number of individual fibers in each tow. So 3K tows will be half the size of 6K tows, resulting in a finer grid. You probably want something larger if you want to see the weave from some distance away. Plain weave is what you normally see on automotive stuff, so it's what people "think" carbon fiber looks like. But 5HS is stronger and more typically used on real structural parts. Strength wouldn't matter in your application though.

I've seen plain weave and 2x2 twill used for "cosmetic" applications... I'm trying to decide between the two. Also trying to decide on 3K vs 6K, but would like to see the difference in person. I guess I could go to TAP and look at their 3K cloth, and if it's too small, I can get 6K. The 3K has a big plus in that the lighter weight would be easier to form.

Suppliers that I have found, and prices for 5.7oz 3K fabric (per yard):

TAP $65.00
Fibreglast $59.95
U.S. Composites $43.50
Jamestown Distributors $45.00
Soller Composites $35.99

Soller Composites also has great info on their website, and a much wider variety of products. Carbon Fiber biaxial braided sleeves. Carbon Fiber/Fiberglass 2x2 twill dyed to sample.

http://www.solarcomposites.com/

[okieflyr]

The Kevlar can look cool as a hybrid into the carbon weave, but it will add another level of difficulty for edge finishing. The carbon will be stiff when sanding and buffing, but the Kevlar being ballistic, will fuzz as the resin will exit the fibers. Using CA will help to solidify these fibers again fo further finishing. Also UV exposure will play havoc with your resin choice and may play apart in discoloring of the Kevlar. It's all fun though!