Carbon fiber Questions

OK I read a thread somewhere months ago pertaining to someone making so purely DECORATIVE items for their bike using CF cloth. As I remember due to the tightness of the weave the resin has to be forced into the cloth unlike Fiberglass cloth which the resin will actually just SOAK into. Anyway from what I remember the guy just brushed the resin OVER the CF cloth and then rolled it in with a rollerwheel (Looks like a pizza cutter but not sharp) once the resin was dried he brushed the other side and then finished sanded everything and came up with some pretty nice stuff. SO if anyone here has CF experience post up and let me know if this is doable.
SRAD

I've helped make some CF parts a while back when I/we were drag racing boats. We used some Vacuum Bag type things to get the penetration into the CF cloth. On the decorative parts we didn't finish sand them, we shot them with a Clear Gel Coat.

I tried to make some parts on my own (boat dash) but it didn't turn out so well. I used too big a weave in my CF cloth. Looks good in the pictures, but up close, it kinda rough.

You need to have a really clean work area for parts that you want to show off. Start with small parts and Pratice, Practic, Practice! Better yet, find someone that's done it the way you like and let them help gide you.

The 2 men I used to run boats with have passed on and taken their "Hot Rod" secrets with them. It was fun while it lasted.

My old Drag Boat:

Das Boot!

Carbon fiber is tricky to work with.

The most common mistake in any composite resin/weave process is using polyester resin. Polyester resin sticks only too itself, and even then, only if laid wet-on-wet. Polyester resin is also porous, so it is not waterproof. Over time, polyester resin will allow the carbon fiber, which is quite hydrophilic, to absorb water, which will significantly increase the weight of the part.

The second most common mistake is two much resin. As you said, epoxy resin does not soak in, it must be worked through the cloth, but not too much or the carbon will float in the resin. Special rollers are made for the job, but vacuum bagging is also effective. The trick is using barely enough resin to saturate the weave, but not too much. Remember, epoxy is merely the glue that holds the fibers in place--the fibers are the strength. Extra epoxy adds no strength, merely more weight. The proper amount of resin is thorough saturation, but still able to see the pattern of the weave in the surface of the resin.

That said, I always use a slow-setting resin. First I wax the mold. Then I coat the mold with gelcoat or resin depending on the desired finish. Third, I wait for the fist resin coat to kick, then lay out the cloth. Next, I pour a little resin on the cloth and push it around with a plastic squeegee cut from a coffee can lid or milk carton (free!!). Then I lay a piece of Saran Wrap on the resin, which keeps the roller clean. Next, I roll the epoxy into the resin, working excess resin to the thin spots, and finally out from under the cloth to drip on newspapers on the floor. I let the resin set before removing the Saran Wrap, which leaves a very smooth finish, eliminating 90% of the sanding for paint prep.

Great info Ken. I wish we would've had someone in the know back when we were experimenting with that stuff.
And yes we made the mistakes of using standard resins on parts that would be wet. Doh!
I still have some of the catalogs and instructions we used, somewhere in my garage I think. I'll look this weekend and report back, just in case anyone wants to get more serious with that stuff.
Be careful what you ask for though... you might get it. It's a LOT of hard work for small prizes and a little bit of "I did it myself" pride.
Then again, you guys may find out it's your calling and start a business and get Rich making Carbon Fiber Fenders and Huggers for V-Stoms!

As you've undoubtedly found on a CF thread I started here at TWT, I made some side covers and throttle body covers from CF. I didn't use any kind of roller wheel but I think I saw the same webpage you are thinking of. The guy made a hood for his rice racer car.

I PM'd you my number. Give me a holler any time this weekend.

Long story short goes like this:
My wife rearended my bike and broke the frame. After shopping everywhere for another frame I broke down and bought a wrecked one and just cut the damaged part off of both frames and heliarced the good pieces on mine. OK OK before anyone panics here calm down. On the 96 GSXR750 the seat frame bolts to the main frame via two perches that stick up about 6" this is a NON stressed NON suspension part and merely supports the rear section(tailsection) that the rider sits on. After the new pieces were heliarced on and the aluminum retextured to match the sandcast finish I discovered something I hadn't bargained for the wire in the welder was a slightly different composition than the frame and as a result a different color. So although no one really notices the weld line I do and it really bothers me. I tried to polish out some of the metal in that area of the weld with the same results two different colors of metal.
Well I heard about a company online that makes a PLASTIC snap on glue on cover that goes over the frame and has a chrome finish to look like a Polished chromed frame. GREAT! This would hide my ugly spot till I saw the price! $375 just for the frame covers!
After some more research I found a CF frame cover for a mere $589.
SSSSSOOOOooo you can see where this is going, this is merely a cosmetic deal just to cover a small ugly. During the 80's it was pretty common to see raceBikes with CF frame protectors so that was the inspiration until I found out about high prices and limited supplies. Well now I have a supply of relatively CHEAP CF so I am thinking about undertaking this project again.
KenH you mentioned "Slow setting " Resin Does this set alot slower than regular fiberglass resin" where would I need to purchase such? the idea with the saran wrap seems like a great one to keep the mess to minimum.
As for the actual part I was really hoping to get by the lazy mans way and lay the CF directly onto the frame rails as opposed to trying to pull a female mold off of the frame then using that to make a plug to mold the CF over and the place that on the bike.
SRAD

Good luck laying up carbon fiber directly on the frame. Use the Saran Wrap so you won't be sanding for months. Do not let the sanding dust from carbon fiber get on your skin, in your eyes, or breathe it. It's a definate health hazard. Another choice between ATGATT and suffering.

http://www.raka.com/

http://www.systemthree.com/index_2.asp

http://www.westsystem.com/

These are genuine marine epoxies. They are more expensive but higher quality and more consistent than utility epoxies. Aircraft epoxies are also available, but the price increase is very large for a very small increase in functionality. I prefer System Three. It is the easiest for me to work with.

Epoxies come in different formulations that affect working time. A fast epoxy on a hot day will kick in the cup in a matter of minutes. In fact, it isn't unusual for fast epoxies to burst into flames when directions are not followed exactly. A slow epoxy in the winter may not kick for a few hours, and might take weeks to cure to full strength. Choose your epoxy formulation based on climatic conditions and necessary pot life. Better to err on the side of too slow and be patient than to have to rush, do sloppy work, and waste volumes of expensive ($31/qt) epoxy.

Epoxy is sensitve to two environmental conditions. The first is ultraviolet light. A coat or two of marine spar varnish will provide protection. The second is excessive heat. Black-painted horizontal surfaces in the summer sun will soften a bit. Not a problem with non-structural parts such as fenders. When riding, airflow will cool the parts sufficiently to prevent problems. Light-color paint will also eliminate the problem.

Ok, why not just use pre-preg?

84SabreRider said:

Ok, why not just use pre-preg?

Click to expand...

Sloppy.

I use Hysol 9396 resin. we put the cloth in a zip lock bag with a glob of resin, close the bag, work it through with a plastic bondo spreader, comb the excess off the end of the sheet, then split the bag, and pull out your wet workpiece and apply. works pretty slick for small stuff, but bagging works best for anything bigger than a personal pan pizza.