I’m working on a project with Smooth-On two-part urethane resin and silicone molds, reproducing dashboard vents for the silver car that spent the last week in the automotive square. Initial results tell me I won’t have much success with passive casting and venting of the molds. I think I’m going to have to do the castings under pressure to achieve acceptable results.
The urethane I’m using for this project is TASK-4, which is a slow-curing resin with a demold time of 16 hours at 75 degrees. I tried Smooth-Cast 327 (40 minute demold) previously, with even worse results.
What I want to know is, if anyone has any suggestions to achieve good results without getting huge surface bubbles in a portion of the mold which is impractical to try venting. Also, as far as pressure casting goes, what kinds of solutions are there at relatively low budgets?
Structurally, the trial pulls have pretty much been solid, except in areas where bubbles have removed structural features like pins. However, aesthetically, all of the castings have been trash due to heavy surface bubbling.
Any suggestions are appreciated.
-Kris