Adventures in moulding.
I’ve been wanting to give resin casting a try for quite a while now, and decided to start with something fairly simple that I’d need a lot of to get some practice in. The perfect thing was replicator blocks from Stargate SG-1. These are made from hundreds of little blocks, and a few people have these for sale on Shapeways. I ordered a few of them as originals, along with a starter moulding kit from Easy Composites. The kit is quite good, and comes with most things that you’ll need to do simple moulds. The only extra things that I ended up getting was some clay and mould release, but that was because I was going to be doing a two part mould.
It would be a waste of time going through the whole process of making moulds as there are plenty of tutorials and youtube videos on the various techniques. I just followed some of them, but I did learn a few things along the way.
With the mould done, I did my first attempt at casting. Whilst it didn’t turn out particularly well, it wasn’t the great big mess I was expecting. I hadn’t taken into account the amount of spillage when I poured into the mould, mainly due to the small entry point, so ran out of resin on the second block.
I’m going to remake the mould now, taking into account a few things that I learnt on the way, along with some tips from experts.
- Make the mould box differently. I used acrylic and a hot glue gun which made it very hard to dismantle. I think I’ll use clay for my next one as I should have enough of it.
- Do the base of the mould first, and press the parts into it before making the box round it. Was difficult to get in to make a clean seam.
- Don’t make the key marks for the two moulds too deep. I did stupidly small deep holes first time, and it made it very hard to pull the mould apart, which leads to….
- Use more release agent when pouring the second half of the mould.
- Make the fill area bigger, and it needs vents to allow the air to come out. It has also been suggested to use an injection technique with a syringe to force the resin into the gaps.
- Make more resin than I think. Its also hard to make small batches, so my next mould might incorporate all four blocks I got from shapeways.
If I get the next one working well enough, it’ll be a production line I think. By my calculations, I’ll need about 200 blocks to make a standard replicator. I’ve also ordered some metal powder to use in the moulds to give the finished blocks a metallic look, along with some black and dark grey pigment which will hopefully mean less painting of the finished product.