I have the good fortune to be around the corner from Tap Plastics...
this has saved me a fortune on plastic for hydraulic dies! At their
full retail price, acrylic plastic costs one third of what any
"jewelry" tool company charges for blanks... including "while you
wait" custom cutting. (And yes, it is the red label acrylic.)
They also sell "Premium Pigment" - a brand of polyester and epoxy
resin pigments, in all colors of the rainbow. Since these are
designed for the purpose, I find them to be easier than trying to mix
up some concoction that may be the weaker for my efforts. You can
blend them to get any shade you need to match.
Brian P. Marshall
Stockton Jewelry Arts School
704 W. Swain Rd.
Stockton, CA 95207