Thread: Silicone Moulds

If you get some 401 silicone and some pine you can make your own in no time at all. You can buy some containers like the take away ones and use that but then you have to cut them up. If you don't have any thing to cut them up with you can wait until they start to set at the gel stage then use a knife to cut them.
David

I have been making molds for casting.. started out as a project for casting labels,
but now I use them for casting colored resins too.

You don't need to drill or glue tubes, they go in to the mold before you pour. And you
use about an ounce of resin for a pair of tubes. So far, so good..

Depending in the shape you want we have a CNC router with 3 axis capacity that can cut any shape, give us a call or visit our web site www.043turning.com.au

Mark

Well i finally had a crack at making a silicone mould with a bit of help and it seemed to work out fine. The mould i made was for just the basic pen blank (4 in total) and i used Barnes Ultrasil it worked out great. I will post a pic soon.
So next step is to try the blank itself. My question is what types of products do people use as a release so my resin doesn't stick into the mould or is a release not necessary ?

Any help appreciated

thanks Ian

Usually that is why Silicone is used as a mould, the resin doesn't stick to it, Amos

Release isn't strictly necessary, as the silicone will release both PR and urethane
resins, but using a release will extend the life of the mold.

There are commercial releases out there (Poly Ease, Stoner etc) but I've been using
mineral spirits and petroleum jelly (about 95% spirits) warmed and shaken. I put it
in a spray bottle and spray the inside of the mold with it.

When I'm making molds, I also use this combination to spray the walls of the mold
box and the masters. I also use a paint brush to get in all the little crevices with the
release. It really REALLY helps with undercuts and with anything semi-porous, as
the silicone likes to stick to cracks and pores.

I've been making mold boxes with four walls and no bottom.. I just use 3" tape across
the bottom of the box. Once I've positioned the masters (acrylic blanks, delrin parts etc)
I spray the whole thing with the release and use the brush to get into the crevices,
but I also spray the tape. \

The tape makes everything easier to disassemble (and assemble) when removing
your mold, but the silicone LOVES to stick to the tape.. and trying to clean the
adhesive off of the silicone mold is better described as punishment rather than
a chore. Using the release stops this, as the tape comes right off of the silicone, but
the tape still holds onto the wood, where it should.

That's made life a whole lot easier..