Covering Carbon Fiber in White Test Panels

Disclaimer:  For 20 years I have only used Resin Research.  Pretty much always will.  Best strength numbers, ease of use, optics, clearity, and I know the product so no surprises.  I'm doing some carbon boards and covering the black for Florida is troublesome.  ProLink has just come out with a pre-prigmented 2:1 resin that they say will solve the strength issues associate with adding pigment.  Even epoxy based pigment is not 2:1 and therefore will have an effect on strength.  So,.....
I prepared 4 test panels of carbon fiber (single layer 12 inches by 5 inches) for the purpose of evaluating the best way to color a black carbon board.  Only color coverage was evaluated.  The relative weight of each panel is easily determined without adding the uncertainty of weighing the panels, based on the lam steps and material used.  I also noted the number of steps required for each, and the likelihood of reducing pinholes.  The four panel color methods are the most common I have seen.  Their maybe others and I'd like to test them, too.
I first laminated panels 1, 2 and 3 with clear resin and panel 4 with pigmented resin.  (I've never used pigmented resin for laminating before because of strength issues.)   I then applied a fill coat as follows:
  1. Resin with 100% by volume micro balloons,
  2. 2 oz glass layer applied with heavily pigmented resin,
  3. Clear resin, cured, then followed by white spray paint, to be scuffed when cured,
  4. Pigmented resin (not Prolink since I don't yet have it)

Panel No.     No. of steps     Rel Weight     Best Color      Fewest Pinholes  

1                      4                         1                      4                       3

2                      5                        4                        2                       1

3                     5                        3                        3                         3

4                    4                         2                       1                           2

Picture below.  Numbered 1 to 4 from left to right.
I choose panel 4 as the best,  but the key is going to be using Prolink pre-pigmented resin.  And under the assumption that their published strength numbers are real (no reason to doubt).  I checked their published numbers against those of Resin Research and RR came out slightly better on almost all key parameters.  However, they were close.  Close enough, with the exception of Barcol Hardness, that they could be considered almost equivalent.  Prolink BH is shown as 80 and RR is shown as 84.  Maybe this would give a sanding edge to RR, but hard for me to tell.  Also, Prolink is pretty certain their additives will reduce pinholes.  RR is silent on this.  My carbon boards have all be wrapped in pigmented 2 oz so this has not been a problem.
In any case, I like the notion of a pre-pigmented resin so that strength isn't compromised by a pigment additive.  I think this is going to see wide use in the carbon board biz.  And good for them.

I think most places lam with clear then paint a polyurethane coating for the color. Seems like that would be easier.

I’d would use Carbon Fiber if I knew how to laminate in a bag. Heck, I’ve only used the bag myself twice, it’s always been me helping Bernie.

I take your point, SC, but spraying PU properly is tough for me.  I think just sanding pigmented resin will be easier.  But that’s just me.

all the best

I spray clear and colors over glassed boards, but use rattle can crap. One day, I’ll use a spray kit Bernie gave me and do it right.

From my tests You have to had way more pigment past to noticeably modified resin properties than what You need for coloring. And what You modified is You reduce stiffness and increase elongation to break, not necessairely a bad thing.

Mat, Is it still a good rule of thumb, up to 3 percent pigment per mixed batch of resin, before there is an adverse affect?

Greg, thanks for doing the tests. On my last carbon fiber deck patch I pigmented the resin during the lam. Not a 100% white-out but enough for me to feel good about not setting up an EPS meltdown with black materials in direct sunlight.

I had trouble seeing the numbers so I added them in on the pic below.

With specific for resin coloring past you can add up to 10%. For lam i avoid to go up to 3% too.

Yeah Greg!  This is the kind of stuff we need more of around here! How do you evaluate # of pinholes… with a magnifying glass?  Several ways around those including sealing the foam with epoxy bog to minimize resin drain from the laminate.

I am in agreement with LeMat… while theoretically weaker, the actual material properties of epoxy seem barely affected by moderate use of pigments.  I have used white pigmented resin to laminate and fill coat carbon to get that ‘scrubbed hippy/acid washed Levi’s’ look.  It all seemed good.

Thanks y’all. Lemat I agree with you and on a basic short board I wouldn’t worry too much but on a 12 ft prone paddle board for which I have paid $100’s for the carbon fiber I want it as strong as it can be. 

John, Prolink tells me they are putting some additives in to help with the pin hole issue. But on panel tow I used 2oz cloth as a sacrificial sanding layer and assume that that helps mitigate the pin holes. Just an assumption. I really like the look of my test panel with Prolink.  I’ll update when I have something to show. 

All the best

J, thanks.  that is a killer paddle board you posted.   I should be so talented.  But I’m not.

all the best  


I have just been testing the same thing myself trying to find a way to do a sandwich but keeping the temps down but still having the benafits of the carbon stiffness. 

I have been experimenting with laying up with white pigmented epoxy with 4 and 6 oz over the top, there was a significant differeance in tempriture between the two with the 6 being slightly more opaque and cooler. The white 3D corecell was the best however which has carbon on the back and 6 oz glass on the front. The cork allso performed quite well. The silver cloth over carbon did not make a huge differance.

I have just orderd a few samples of coloured glass to try from this place