Is it necessary to vacuum or pressure the Clear, Slow Clear, Water Clear and Flex systems?Updated 23 days ago

Not in order for it to cure, but yes, in order for it to cure with absolutely no air bubbles present within the cast piece, as well as the best physical properties. Both of these materials start out at a higher viscosity (thicker) than the lower viscosity, fast cast Alumilite resins. Therefore, when these two materials are mixed, the viscosity (consistency) of the material does not allow the air bubbles to freely find their way to the top of the cast piece as the other much thinner resins do before the material cures. These two materials feature a slightly longer open/work time in order for you to either vacuum and/or pressure cast to eliminate all of the bubbles within the casting.