I've been experimenting with Alumilite to mold some grippers for my bots. Build the prototypes in plastic - cut it down, drill & file and smooth, etc. Then pour a mold around it using the RTV silicon rubber. My question: Is there a cheaper alternative to RTV Silicon Rubber for making molds ? As I go through several iterations of improvements and learning curve I have already used up the RTV Rubber from the kit but have plenty of the plastic left.
I tried Plaster of Paris (captured detail great, but too dang hard to get the part I created out of the mold). I also tried Silicon caulk from Home Depot (the unpaintable kind that doesn't stick to plastic very well ...) but it didn't cure even in the summer heat for over 24 hours because it was just too thick. Perhaps I could paint layers to build it up but that would takes a loooong time, I would guess.
I know some of the people on here have spent time in the special effects/movie industry so I figured this would be a good starting group for this question. I suspect the answer will be to simply get more skilled at doing this and become more economical with the RTV Rubber!