Current update: machine oil is no good to separate different layers of rubber. I've just spent a nerve wracking 10 minutes carefully cutting the master out of the block in approximately the correct place around the top of the Lc. Vaseline is the way to go.
I'm using easycast resin for the first time here, and while I'm impressed with the viscosity, I do have a minor problem with it. Back in the old days when men with mullets roamed the earth, I used epifill as my favorite polyurethane. this was a mix A with B in a 1:1 ratio, but it was nice and thick, and you could do it with a screwdriver and then smear it into the mould. the amounts could be measured by eye. with this stuff, you measure it by mass, and I fear my cheap plastic scales might not be up to it. on the other hand, the 2 piece mould has dropped into place under its own weight, is nicely lined up along the sides, and all things being equal, should work a treat.
Update; second time around, got the mix right. Had a stack of moulds on hand, and only got 1/2 of them filled, as the resin went to a rubbery form inside 3 minutes. will have to learn to be much faster, or work somewhere thats much colder.
First casts had air bubbles all round the place in the 2 part mould that I've had a go at fixing second time around by forcing the resin into the courners and edges etc.
Subscribe to:
Post Comments (Atom)
2 comments:
I found industrial talcum powder works really well for getting rid of bubbles in castings. A light dusting of the mold is all it takes. I've been able to cast really small stuff (e.g. injectors) with almost no wasted castings since using the stuff. Works for white metal too, evidently
I'll give it a go, but I'm not sure its going to quite solve the problem. I'd love to be wrong though :v)
Post a Comment