DIY dying cement is a tough job. Cement is often a dark media (my favorite crafting variety, Rockite, however, is already light, making dying easier) and the chemical processes and heating that take place during the curing process seem to destroy most pigments.
In my initial attempts, I used a professional grade high pigment fluid acrylic paint and was shocked to find literally no trace of the color after the cement cured. In subsequent attempts I tried alcohol based dyes and even a super powerful resin pigment, each time uncasting my cement to discover no color visible in the final project.
Finally, after trying all these methods to add color to my cement castings, I found myself at a craft store clutching a grossly overpriced tiny bottle of cement dye and I just couldn’t do it. One more attempt at scouring the internet for cheaper alternatives to achieve dyed concrete turned up an idea to try the dye that hobby soap makers use: pure pigment.
Pigment, dye, and colorant are all words used pretty much interchangeably, but they aren’t the same. While colorant is a word that includes both dyes and pigments, dyes and pigments are not identical. Dyes are colored chemicals that are dissolved in a solution while pigments are colored particles that can be suspended in a liquid but remain distinct structures from that liquid. Consider: a bottle of dye-based stamp ink never settles and separates carrier from coloring, but quality watercolor mixed heavily in water, because it’s pigment based, will eventually settle at the bottom leaving a clear glass of water.
SO PIGMENTS WORK TO DYE CONCRETE?
Well, kind of. In my testing, it appears that the pigments made up of larger particles do a much better job of dying concrete.
What didn’t work: Resin dye, Liquitex Basics acrylic paint, craft store paint, or even Liquitex High Flow Acrylic Paints (which are artist grade, pigment based, and extremely powerful colors in other media)
What did work: Raw organic pigment. (wow, that sounds like something from Whole Foods!) Pure Titanium Dioxide produced dramatic color changes with the addition of one or two tablespoons of powder per pound of cement.