Talk Composites - The Forum for Advanced Composites

New guy to carbon fibre and the forum

http://www.talkcomposites.com/Topic5722.aspx

By dr3bin - 4/9/2013 7:24:29 PM

Hey everyone,

I'm new to carbon fibre. Took an interest after looking through Carbon Mods and watching their videos, so I thought I'd give skinning a go as I have a few parts I'd like to carbon-fibre up

I have (what I class as) a 'fairly simple' shape. A spark plug cover for my car. First time I've ever skinned anything, so I knew it'd mess it up. Which I did. A load of times. However the finished product finally came out and it looks like this;



The major issues I have is the finish is rubbish. I didn't go up the grades of sandpaper long enough and you can see fine lines. There's little white dots in the resin which I believe are air bubbles. Hammering it with a low-temp heat gun didn't get rid of all the air, so it appears. Also the resin became contaminated as I re-used a brush (washed and soaked in acetone) with fresh resin for the final layer, but the resin dried as a complete fog instead of nice and clear. So about 8 hours of sanding pursued to get it to a semi-finished state, as above. You can kind of see the fogged resin along the bottom of the part. I've learnt from that to use a new brush for each layer.

However, my main gripe is how on earth do I prep the carbon fibre cloth to accommodate the bolt holes. On the above example, I skinned the part, done all the resin layers before drilling the holes through - starting with a small drill bit and working my way up. But, this messed it up as the part eventually chipped around the edges resulting in a poor finish, rather than leaving it with a nice edge to work on with a file to get a nice, flat edge. Took me about 30 minutes of drilling as I knew to take it slowly and carefully. 

I tried cutting the fabric prior to laying the resin, however this frayed the cloth and put it all out of alignment with itself. I can't re-use the part as the fabric is bonded to the part so I binned it

I'm getting pretty annoyed with this process as I want to get this part perfect so I can sell it to my car club. I know I can do it, I'm just missing knowledge that a training course or other, experienced people would be able to offer. Thus me joining up on here Smile

Any advice would be greatly appreciated
By matthieutje65 - 4/11/2013 2:02:33 PM

dr3bin (11/04/2013)
Good video. So that guy goes with one thick layer rather than the 'multiple thin layers' process. Something else to try - although I know if I go with a thick layer I'll get 'pools' of resin in the recesses where the bolts go, so that'll make things interesting when I come to drill through the carbon once cured fully

Looks like he left the basecoat to dry fully instead of going to a tack as the plastic sheet didn't 'stick' to it when he placed it upside down on the bench
I would indeed do this in a different way and let it go to a tacky state, to improve the bond with the resin going on top and that black basecoat, 


I would of liked to have seen how he trims the excess off the back of the part, as I don't imagine he left it all stuck to the back with the double-sided tape
The triming shouldn't be that difficult? trim of the excess with a dremel or sand the edge till you are through the carbonfiber...

All good to see though. I'll have to try multiple processes to see which works best, or mash a few up to best suit me


In addition to this I can show you a video I've made on how I did some "skinning" on a helmet I've made, I Had some dry spots so I've added some layers of resin on top of it (like the skinning process)

worked out great for me but took me loads of time but I'm very happy with the result!

Carbon mods also did a video on this 


Best of luck and share your test with us Wink