HELP!! Cracked carbon fiber fixes/ideas

[Andrew_Holly]

I ordered a carbon fiber front lip on Ebay for my M3. Unfortunately, it came slightly cracked (just the clear coat). I reached out to UPS but they denied the claim. I can ship it back to the sender, but that would cost $60. I watched a couple videos on YouTube and the fix looks time consuming, but pretty simple. What should I do? Thanks!!

[bvrider1]

you can try to apply some resin and it might fill in the cracks. I did to one of my front splitters and it turned out decent.

[cmyE93M3]

It's an easy fix, wet sand it down with 120 grit to make short work of it, do not over sand into the carbon, if you start to notice the paper going black from hitting the carbon stop. Once done, mix up some epoxy resin, brush it on, do several coats but apply even, don't be sloppy as it causes more work after the fact as you need to wet sand it again once the resin is 100% dry. Work from 250 grit up to a 1,000 (by hand) and then high-speed polish with some cutting paste and finally a buff.

[Pig Farmer]

Send it back. Seriously, it will cost you less in the long run. You can try to wet sand the cracks and re-spray with 2k clear coat, but be warned... If you sand down into the the carbon fiber weave, the pattern of the weave will not be uniform and will creat strange reflections. You won't notice it until the clear coat is applied. Don't try to apply resin unless you are experienced with laying down a hot coat. Take my word for it, you will spend more than $60 in materials and several hours before getting it to look half decent.

[BOOF-M3]

This is something else. You purchased an item expecting it to arrive as advertised and either the seller or shipper screwed up but you have to PAY to get what you PAID for.

[6ixSpd]

How the hell did UPS deny the claim? Time to file a PayPal claim they're very good about stuff like this, usually.

[///M3Fresh]

Originally Posted by BOOF-M3

This is something else. You lurched an item expecting it to arrive as advertised and either the seller or shipper screwed up but you have to PAY to get what you PAID for.

That's exactly what I was thinking... I'd deny charges with PP and OR CC and see what the seller says after that. Ship it back only if provided a prepaid label.

[dparm]

Originally Posted by Andrew_Holly

I ordered a carbon fiber front lip on Ebay for my M3. Unfortunately, it came slightly cracked (just the clear coat). I reached out to UPS but they denied the claim. I can ship it back to the sender, but that would cost $60. I watched a couple videos on YouTube and the fix looks time consuming, but pretty simple. What should I do? Thanks!!

If the seller won't give you a return shipping label, just spend the $60 to send it back and order a new set. It won't be worth the time and hassle to try and fix it, and you stand a good chance of making it worse.

[deansbimmer]

Make them take it back....

But, If you want to fix it, Buy a little bottle of THIN cyanoacrylate (CA/superglue) from a hobby shop. You can also find thin 'flexible' CA which is a good match for thin panels. The reason you want this is because it's so thin that it wicks into the cracks and wets the cloth, rendering the cracks and delamination invisible. You can then sand and polish as you wish to smooth out the surface. Sanding won't take out those cracks, and resin is too thick to wick into the cracks.

[Pig Farmer]

Originally Posted by deansbimmer

Make them take it back....

But, If you want to fix it, Buy a little bottle of THIN cyanoacrylate (CA/superglue) from a hobby shop. You can also find thin 'flexible' CA which is a good match for thin panels. The reason you want this is because it's so thin that it wicks into the cracks and wets the cloth, rendering the cracks and delamination invisible. You can then sand and polish as you wish to smooth out the surface. Sanding won't take out those cracks, and resin is too thick to wick into the cracks.

This is an interesting suggestion. Do you have experience with this method. I often see a haze form when using superglue. I guess if you block sand with 400/wet paper to take down the haze without cutting through the cleat coat. I would probably lightly sand the whole piece and hit it with 2k clear coat for a uniform surface and additional UV protection. I've had great success with the 2k that comes in a rattle can, although the fumes will kick your ass without a respirator.

[///M3Fresh]

Originally Posted by deansbimmer

Make them take it back....

But, If you want to fix it, Buy a little bottle of THIN cyanoacrylate (CA/superglue) from a hobby shop. You can also find thin 'flexible' CA which is a good match for thin panels. The reason you want this is because it's so thin that it wicks into the cracks and wets the cloth, rendering the cracks and delamination invisible. You can then sand and polish as you wish to smooth out the surface. Sanding won't take out those cracks, and resin is too thick to wick into the cracks.

good to know. I've played with some CF and never tried this.

Originally Posted by Pig Farmer

This is an interesting suggestion. Do you have experience with this method. I often see a haze form when using superglue. I guess if you block sand with 400/wet paper to take down the haze without cutting through the cleat coat. I would probably lightly sand the whole piece and hit it with 2k clear coat for a uniform surface and additional UV protection. I've had great success with the 2k that comes in a rattle can, although the fumes will kick your ass without a respirator.

I would be willing to bet the same type of super glue is what windshield crack/chip repair places use. If done right it does hide the cracks well.

[deansbimmer]

Originally Posted by Pig Farmer

This is an interesting suggestion. Do you have experience with this method. I often see a haze form when using superglue. I guess if you block sand with 400/wet paper to take down the haze without cutting through the cleat coat. I would probably lightly sand the whole piece and hit it with 2k clear coat for a uniform surface and additional UV protection. I've had great success with the 2k that comes in a rattle can, although the fumes will kick your ass without a respirator.

Yes I used to work with aircraft composites, it's a handy trick for minor touch ups and edge or hole fraying. The blooming (white residue) can usually be wiped off. It not and/or you need to sand the surface to level it, just touch it up with 1000 and polish the surface. (400 is too coarse). I'd also suggest paint protection film for carbon parts over using a can of 2k convenience clear. Although better than a can of typical lacquer clear, it doesn't have the high solids performance or durability of a real two part reduced urethane. Wrapping the splitters with protection film gives the part UV protection, a little extra strength, and obviously keeps the part from chipping and looking like garbage in a month or two.

Edit: If you can find some, low odor CA glue doesn't bloom as much. It may also be sold as "foam safe". (CA glues melt foam).