Question for Carbon Fiber/Paint Guys

[Randy@StradaFab]

   I am laying up a CF seat from a mold that I made for my Monster. I want to paint a stripe on the CF but I wasn't planning on using gel-coat in the mold, just a clear coat after. Do I need to use the gel-coat so I have a smooth surface for the base coat?

[ducpainter]

Most of the carbon I've worked with has been vacuum bagged and has a fairly smooth surface with no gel coat.

I clear/paint/clear.

[BlackKat]

Most of the carbon I've worked with has been vacuum bagged and has a fairly smooth surface with no gel coat.

I clear/paint/clear.

X2

Then reclear  ...also, UV resistant clear is your friend...

[Randy@StradaFab]

Thanks guys,
  I'm doing vacuum bagging and planned on doing just what you said...I was a little concerned with shooting a base coat for the stripe over the clear and having the clear "lift".

[ducpainter]

Thanks guys,
  I'm doing vacuum bagging and planned on doing just what you said...I was a little concerned with shooting a base coat for the stripe over the clear and having the clear "lift".

Usually base coats will not lift a clear unless it's really 'green', and you sand through the clear below to another base coat, or apply the base to the point of sagging.

[Case S2R]

I do not know of a single use Gel coat is used with carbon, so I would not use it, just resin.  Once the part is made,
1. wipe it down with Acetone and remove all the mold release. 
2. You can now sand the part with 400 (You can also sand before Acetone prep).
3. Prep
     A)  Wet lay, excess resin should fill any pinholes so sand with 400 and shoot.  If you have blemishes treat it like pre preg.
     B) Pre Preg, depending on your resin ratio woven will give you pin holes between each weave, you can take care of these two ways
          1. Shoot with clear and sand it down, use your hand (with a glove) to rub clear into pinholes, I use a high solid clear but it will work with standard clear, just take your time.
          2. Hit the part with a black filler that will blend into the carbon, then shoot with clear.  If you use filler do not sand too deep, the squares of woven will get little circles on the top.  You can run it under water to see where you are.  I do not think anyone will ever notice but someone that knows carbon will be able to tell.
4.  Once you have a base of clear scuff with 400 and lay color.
5.  Finish it off with a layer of clear

Hope it comes out good,
S2R



 If your part is woven be carefull not to sand too far, you will turn your the carbon squares in the weave to circles (This is mainly for Pre Preg, wet lay will have enough resin to fill in all the holes and will require less sanding).  If you do sand to get circles, I doubt anyone will ever notice unless they really know carbon.  Depending on your resin ratio (pre preg) or

[Randy@StradaFab]

Thanks! Any tips on mold making over a foam mold. I carved a seat pan from foam and laid fiberglass with epoxy resin over it to get the mold. Had a few small voids, nothing major. Looks good to me. Any other techniques?

[Case S2R]

1 word, Vacuum

You could have a complete forum on that topic, but if you are dilligent you will figure it out.

Case