Wednesday, 25 November 2015

Silicone moulds for resin casting

After leaving to fully cure overnight, we turned out our test moulds. As the fingerboard was only held in place with a few strips of double-sided tape, it was easy enough to remove from the backing board

And when the master was removed, we had a very impressive looking mould. Sure, there are a few bits of burnt mdf stuck to the silicone, but we're pretty confident that these will come off with the first cast or two, made with our two-part resin (and if it doesn't, it's not likely to affect future casts either)

Our little test miniatures look promising too

After removing the play-doh and a little cleaning up with a knife tip

Unfortunately we forgot to add in some "pouring channels" with the front half, so we'll add them in before adding the back half of the two-part mould

The idea is that when fully cast, the two part mould will have two channels running from what will become the top of the mould - the first being a channel into which we'll actually pour the resin, the other being a vent to allow air to escape as the resin fills up the mould.

Now we just need to make up some more silicone rubber for the second half of the two-part moulds, and we'll be ready to actually start some casting.

We're holding off just because when we mix up a batch of resin for the guitar neck, we'll be able to try out our two-part moulds with the excess (there's always excess, since we always manage to mix up too much, for fear of not making enough!). Our polyurethane resin is also pretty stinky, so it's not something we want to have hanging around the place - we'll mix it up, pour it and let it go off overnight, at the unit, so the smell doesn't upset anyone while it's going off!