Colouring Epoxy Resin
Collated from newsgroup postings.
I use Lamp Black powder (pure carbon) available from the art supply store. It doesn't take much, and it has no bad effect on the epoxy. I mix the carbon into one of the two epoxy parts before mixing them together because I usually use the 5-minute variety, and I get a longer working time that way. Some people use black pigment from the paint store, or fabric dye, but I prefer the lamp black
I used a few drops of black leather dye. Worked very well with 2-part 5 min. epoxy. I also added some brass key filings to the top, let dry and buffed out.
I have used photo-copier/laser printer toner. It's very black.
Use artists oil paints. I tried it and it works great. The paint must be oil paint.
On using an artists paint or other other oil based medium for coloring epoxy;
It should not be used as a structural adhesive. The oil paint, and its solvents, have the effect of changing the chemical composition and properties of the epoxy, and reduces its strength and hardness. In the extreme, it will cure to a weak rubbery consistency.
Dry pigments such as lamp black, colored chalk, and aniline dye can be added without sacrificing the strength or hardness of the cured epoxy, because they do not alter its chemical composition or properties.
Tempra powders (add water to make poster paint) provide a large variety of brilliant colors, and they are compatible with epoxy.
I have found that mixing powders in too high a concentration will cause the epoxy not to harden properly. This was quite high (like maybe 50%). I have been able to get real nice colors at much lower concentrations than that so you shouldn't have a problem.
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