carbon fiber repair of nocom
 

I had some problems with some cracks appearing in the gelcoat on the nocom that shouldn't have been there. I'll be getting a new warranty frame but for the meantime I had to do something to slow down the damage. It would take quite a while of riding the bike before total frame failure would occur, but I didn't want to take any chances. Dana and Kamil suggested I lay some carbon layers over the affected area. 1st picture is the stress damage. second picture is after sanding and prepping the area for the west system epoxy lay up of the 10k 5weave and 5k 2x2 twill patches. The epoxied patches will be pictured tomorrow. Next will be sanding and refinishing the area to make it better blend back in. 3 days before I can ride the bike in order to give epoxy full time to cure.

Wow that crack has really grown since I saw it last! Does this mean you're back to riding the VK2 for Assenmacher 100 on Sunday?

nope, I'll be riding the nocom. The area is now repaired. The expoxy layup will be fully cured by sunday and ready to ride. I have a bit more cosmetic work to do on it, but this is so far after sanding with a bit of polishing.

here it is with the first wet layer of gelcoat before I steel wool it and apply second coat. I'll do the assenmacher with the first coat applied and worry about the next coat later.

If you get more cracks you can try 4 to 1 fast epoxy hardener listed at the bottom of the site page.
http://www.shopmaninc.com/epoxy.html

I have used this epoxy with carbon tape for many repairs and mods to carbon frames. It cures in 4 hours and quicker under a heat lamp or outside with sun exposure on an asphalt surface.

After sanding the repair a couple light coats of spray lacquer will give you a smooth clean surface.

AA

thanks alan, that looks like a pretty good deal there. I'm starting to get the hang of carbon repairs. It looks like as long as I own carbon bikes, I may as well get some knowledge in carbon repair. I bought my carbon 4x6 swatches from fiberglast.com for only 2.95 each. got the west system expoxy for 10 bucks from jamestown distributors. http://www.jamestowndistributors.com/userportal/main.do

there almost done. almost can't tell that there has been any damage repair done.

a bit of polishing now and all done.

You guys amaze me. I wouldn't know where to start. If my VK2 cracks, you guys are going to be on my speed dial! :)

Very nice work.

1 more pic from slightly different angle of almost finished ............ final gel coat layer still wet.

I wouldn't worry too much about the vk-2 I sure didn't have any problems with my second vk-2. The first one I had was a custom 650c rear wheel model with a campy hiddenset. The boom clamp bolt pulled through the carbon. I epoxied the boom in place and that fixed that until I got a new frame out of that deal. I feel sorry for Kamil having to dish out warranty frames from time to time, but on the other hand when you dish out the kind of money for a bike like that, I think it should be done correctly and not fail within a year. Now if you crash your bike.......... well now, that is another story. There are lots of guys on the forums with carbon bikes who have done way more carbon work than I have. I really have to give Alan props for the fantastic work he has done with his various carbon bikes. Viewing his posts gave me the inspiration to tackle the repair with some level of confidence.

I agree. His built up paddle brake levers recently were really cool.

ok, all finished, gel coat dry and electrical border tape removed. The repaired area is not perfectly finished like the rest of the bike of course. I would have to spend hours and hours buffing. I'd rather spend hours riding. I think by adding the electrical tape both top and bottom of the repaired area, it defines the area with a slightly different finish, but at the same time looks like it may have been intended to be that way by someone else looking at the bike.

What you should've done with the electrical tape, after applying the wetted-out carbon fibre weave to the area, was turn it sticky side up and wrapped the dry side to the surface of the wet area.
It forces the epoxy deep into the weave and all those vital scratches on the repaired area. It also forces air pockets out of the job, leaving a much more compact and stronger repair, and forcing the edge of the carbon strips hard agaisnt the original surface, meaning less chance of de-lamination of the cured surface. Excess, unneeded resin also exits the area.
If you havent went overboard with resin (repair area and both sides of the carbon should be wet out fully yet lightly) then all you would have to sand is tiny tape marks. If you have overdone it with the resin then you'll find the tape simply bulges and stretches as it can't get the resin out quick enough, resulting in a rippled area that needs much sanding. Tip for next time I guess.....

EDIT: I've gotta say, I never get sick of looking at lowracers. You own an amazing piece of machinery, lowracer1 :love:

Thats the exact method I used with the electrical tape. I didn't show a picture of the repair covered in tape. after the carbon was cured, removed the tape and sanded. the gel coat however brings the level up higher than the original surface. Too much work to feather in the gel coat surface to match the original. The quality of the original surface is almost flawless. Feathering the two surfaces together still wouldn't look right.

On a repair with masking tape, a sharp ice pick can be used to punch many small holes in the electrical tape while the area is curing. The small holes will allow excess epoxy resin to drain thru the tape. The excess can be wiped off with a paper towel. Minimal sanding is required when the tape is removed. Adhesive side up or down makes no difference for small repairs with electrical tape to apply pressure.

Your repair looks very good. The NC3 did not have a gel coat as that option reduced frame weight. The local NC1 & 2's all had gel coat finish.

sweet repai. Do you have to send the fram back to kamil or do you get to sell it to me cheap? :)

If you're needing to punch holes in your tape, then you've used too much resin. The edges of the tape are all that should be needed for resin to escape. Plus, by taping you're trying to replicate the characteristics of a vacuum bag repair, albiet with less effective resin extraction. By putting holes in your tape you are simply weakening the tape and thus it stretches, meaning some of the pressure vital to extraction is gone.
True, but the sticky side is always the sticky side, regardless what its been exposed to (in this job). I know what I'd choose if I wanted to make life slightly easier.

It depends on the amount of tape used and the size of the area wrapped. If adhesive side down on a small surface repair, all the excess resin will not leak out of the edges. Pin holes in the tape are similar to perforated film and allow for more resin to escape.

However, the strongest repairs are made by vacuum bagging.

Do you know anything about using peelply for construction or repair? I get the impression that peelply leaves a clean surface that requires no additional finishing.

There is some brief info listed here about peelply but I'd like to find out more about it.
http://www.blids.nl/gallery/Carbon-R...-Workshop-2004

AA

Peelply, when peeled off a cured area, leaves a rough area. It just means that if you were needing some rough areas on the job for future layers, that you wouldn't have to sand the area, which takes alot of time. You simply put it on the wetted out areas that need to be rough, then chuck your vac bag layers on. When it's cured you just peel it off- easy as that :) . Great for composite fairings where you need to install brackets etc that would put a hole in a vac bag.