Same process I've talked about in earlier posts: sign vinyl and just rit dye in water. AFAIK, the only things they dye are the "tri-fly" symbols, which are pretty durn simple, the rest of their stuff is actual custom stamps. I imagine they have a stack of precut templates sitting in their workshop, and whenever they want to dye a disc, just acetone the factory stamp away, slap the vinyl cutout on there, and dip it in the dye. I don't know if they have a plotter to do it all themselves, or just get a sign shop to cut out the templates for them.