Color epoxy to show dry spots on carbon

On the surface of it adding die to epoxy in the middle of the layers should reduce strength.

So the question is how much? Is this a really bad idea to use white or yellow epoxy to infusion and/or vacuum bagging?

In a perfect world adding a die with uv protection and a contrast to the material would avoid dry layup in the final product. That is small color changes can be spotted to show a vacuum layup came out too dry for example.

 

If the appropriate pigment is used (and amount), no appreciable interlaminate bond strength will be lost.

 

Pigments tend to get filtered out when infusing, so you can't add enough to help much with UV protection.

 

A pigment wouldn't be the best way to get UV protection, as the percentage would be way too high to offer much. Clear UV inhibitors can be used, but a solid understanding bisphenol chemistry is a must.

 

What is an epoxy pigment? The stuff you normally see is more of a polyester pigment?

 

You may want to see some data:

http://www.westsystem.com/ss/adding-pigments-to-epoxy/

I use pigments pretty regularly and employ tempera powders, which permit a denser resin charge, without peel strength concerns. There are a number of products you can use, some dies, others particulates, many compatable with styrene and bisphenol resin systems.

 

My boat was built using dyed resin/hardener that is green in color. My guess is blue and yellow dyes mixed from resin and hardener. The hull was hand laid up and cured in an oven while vacuum bagged. This was before infusion becoming popular. The dye seems quite effective. I easily spotted resin rich areas when working on the deck.

 

After some experiments the outer layers of stuff seems to show resin is there or not. Aka flow media turns shiny. If you are laying up a 36 cat hull as I am their is a need for a layer of glass. That is infusion carbon fabrics are loose weave so you want something smoother over the top to finish and you really don't want to sand off that nice carbon.