I need suggestions for good materials to use for molding and casting..(details inside :) )

I need some casting(?) material ideas. I'm looking for fairly inexpensive material to make selector knobs (so it needs to cure to a hard, strong material)...would that material work also for casting things like remote control casing? If not, what would be a good material?... then i also need to make some thermocoupler holders, which need to be able to handle 300 degrees for a very long time. a hard material would be preferable, but, something with a firm rubbery texture would be ok also.... THEN, what material would be good for making the molds to pour the casting materials into to form those items? First, I'd want something solid i could cut into to form the shapes I want to cast, then I need something to put over my first cast(s) after I 'fine tune' them so I can make more.....So.. any ideas/suggestions?

kirnex6 years ago
One of my preferred methods for such endeavors is to use cheap outdoor (for greater heat and light resilience) trim silicone to cover the object in, then before removing it, I make an overcast of plaster or cement to stabilize the piece. Easy-cheesy, and about as firm as you can get--cement will definitely provide heat-resistance, and--since it absorbs the heat, it will give you increased work-time and better control, and thus result in a better cast product. There are also various grades of silicone that have different heat-resistance levels; don't know if outdoor trim silicone could stand 300 degrees for prolonged periods, but it's worth a test!

I've also been mulling over the idea of trying out an agent like "Liquid Nails" to make more rigid forms--I'm betting that stuff is pretty heat-resistant, since it's often used as a tile/stone mastic for fireplaces. Might be worth a go. Might want to go peruse the caulk isle of Lowes to see if you can find something that specifies it's heat resistant--maybe you'll find just what you're looking for.

Good luck, and let us know if you figure it out.
lemonie7 years ago

I have cast lead in cheap household filler. Cheap white-ish powder you mix with water (like image)

frollard7 years ago

cheap?  small quantities are affordable.  They offer everything from cast-making rubber to moldable urethanes, silicones (can handle high heat), and otherwise.