I am going to be infusing multiple layers of Kevlar in a female mold to make a 1 meter long racing RC sailboat. Because low weight In this boat’s class is critical (grams count at this scale) I do not want to paint the part, but I would like to have the hull a different color from the other natural Kevlar hulls as a visual aid to help pick out my boat on a crowded starting line.
Can you tint or color infusion epoxy and if so what is the best product to use?
SS//
You can use pigment, but I doubt it wil be a solid color. I have no experience with this but it seems that you need to apply some glas in front of the kevlar to get a good color saturation.
You can just use epoxy pigment but like the others say it will be a translucent colour.
I have infused coloured epoxy resins with fglass and soric and it looks great having the white soric core to make the colour quite bright.
With a little more digging I found that Fiberglast carries a pigment that will provide opaque colors to epoxy and PE resins. It comes in white, black, yellow, red and a light blue. http://www.fibreglast.com/category/pigments I had anticipated that I would only be able to tint the resin, but it looks like when mixed at about 6% it actually provides opaque colors, which is just what I wanted.
However, I was concerned that it would increase the viscosity of my 250 cps resin too much for infusion so I emailed their tech support. Here is what I asked and what they said:
Can your epoxy pigments be used to color low viscosity resin infusion resin? I am concerned that it will raise the viscosity to the point it will interfere with the infusion process
Our Pigments work with Epoxy, Vinyl Ester, or Polyester resin types.
We have customer using resins as thick as ~1,000 cps in an infusion application…and some as low as 275 cps.
Note the way the answer is worded is such that it does not really answer by how much it will increase the viscosity, but at least provides enough assurance that it is worth a try.
Thanks to those who replied.
SS//
I doubt you will have much issue. At 6%, you will only get a slight rise in viscosity. On a 250cps resin, I’d be very surprised if it took it up above 400cps. I infuse with a 450cps resin, so you will be totally fine I’m sure.
I agree, but according to a video on the site the pigment is a paste, not a liquid, so even at 6% it will probably increase the viscosity significantly.
The upside for this part is the greatest distance the epoxy must travel during infusion is less than 500 mm and the epoxy has an 80 min pot life. It may slow the resin front down, but on this very thin part (3 layers of 60 g/m3 slower is better.
Anyway, I will order some and test it
SS//
Tints are liquid, pigments tend to be quite viscous. The pigment I use is so solid you can’t pour it, if you held the stuff upside down it wouldn’t move. But it doesn’t affect the resin viscosity very much at all.
What’s the weight in pigment that you going to use ?
Just curious because 20-30 grams of 2k paint sprayed in a mould can be stretched quite far , however it tends to come out blotchy
What’s the weight in pigment that you going to use ?
Just curious because 20-30 grams of 2k paint sprayed in a mould can be stretched quite far , however it tends to come out blotchy
This is for a 1 meter RC sailboat hull and the bow section is nearly vertical, narrow and deep so it would be very difficult to PITM as you can’t get a good angle to spray.
Since the final surface must be show car smooth it will be sanded and polished so a blotchy finish would creat too much post mold work. It may just be better to shoot a thin water based color coat and top with a thin clear.
I will have to do some testing to see which is actually lighter - pigmenting the resin or painting and clearing. The painting allows more choices in colors, but the pigmented resin would be faster.
I use the fiberglast pigments with Proset epoxies and have never had an issue with viscosity and infusion after colored. Just an FYI: a little bit goes a really long way. The smallest dab colors the resin quickly and efficiently. 
Thanks for the tip.
The product description says it is used at 6-8% to be opaque, so I’ll start on the low end. I would guess that like most pigments, the darker colors require less than the lighter ones.
Another project has just jumped ahead of this one, so it may be some time before I get back to it. When I do, I’ll post results.
SS//