August 29, 2010 – 9:38 am
Fancy making your own moulds, or maybe you have been making them with Siligum- a two part clay-like mixture? Silicone can be quite expensive but not as expensive as Siligum, but sometimes you need it’s properties for making small moulds, which help it to last longer- there’s no pouring it into a large container and having too much waste around the edge! Here’s how to make your own version of Siligum, which can be used for gravity defying mould making (maybe you want to capute a detail on a ceiling rose?!) and repairing silicone moulds too!
NOTES! This has the consistency of cake frosting, so you will need a mixing cup and stick. This only works with addition cure silicones- these are the most common types where you add a 2% catalyst to the silicone liquid. Thixotropic Solution is available at all good silicone suppliers, I bought mine from http://www.tomps.com
1) Pour your silicone into a cup and add 2% volume catalyst (instructions in my book) with the same amount of thixotropic solution (2%). Mix really well until the colour is consistent. I used a fast catalyst (red), but it is also available in slower curing varieties such as blue. I find red works best for this technique.
2) Now you have a thick, gloopy mix! Spread it like a thick layer of peanut butter on the model you want to make a mould of. You can also use it on your skin to make body part moulds though do be aware you will have to stay still for quite a while! This is really economical moulding as you don’t need to put your model into a container. Make sure your mould walls are pretty thick though, about 1cm should give you a long lasting mould.
3) Leave to set for a few hours (half an hour to an hour should be enough for skin moulds) and if it is no longer wet and sticky, then you can peel it away from your model, and there you have it!
You can use these for resin, polymer clay, silver clay, allsorts really! I now plan to test out the flexible additive for polyester resin today and see what happens!
I am off again with the vaccuum former trying to make moulds, the first two attempts proved I had the right material this time, though has taught me about height limitations on bangles and also to really really secure the lock before switching the vacuum on to avoid injury and failure as shown here…
Now the blimming release platform has locked, so waiting for OH to come home and unjam it for me and hopefully I will be able to test my first mould tonight!
Another failure this week was Fletcher- I took him to the BBC Over The Rainbow auditions for Toto and he got really anxious with the two hour wait (not to mention the 45 minute journey in my little car) and the fact that he was surrounded by other dogs that all wanted a piece of him, that when we went into the show arena thing, he wouldn’t look at the judges and wanted to excape- I think he thought he was at the vets! Needless to say he didn’t get through because of how stressed he was (to the disappointment of the carpark stewards), so I now know acting isn’t the boy for him. He was totally exhausted when he got back home!
I got a vacuum former last week- and I can’t get it to work properly yet. I did a tester with some acrylic that came with it and I didn’t let it get hot enough so that was a fail…
Then I thought maybe material would make a difference. Since I wanted to make moulds from polyethylene anyway, I waited till my delivery of 1mm HDPE came and then this happened…
I don’t know if it got too hot, or whether it’s not suitable for making bangles. Maybe I need LDPE so it’s more flexible? But then I have an area where the sheet has pulled away from the clamps which suggest it is too hot (or the clamp is faulty), and it would only get worse if I used a softer plastic surely? Is there a better way of doing things?
*sigh*
I’m quite pleased with how this has worked out. On the left are the buttons I use on my knitting needles with the shank cut off, though I can’t get these anywhere anymore! So what I did was create a mould from the buttons with silicone. I used gelcoat for the brown middle first so that it didn’t run everywhere, then the next morning topped it up with yellow resin and ta da!
December 17, 2008 – 11:39 am
The mould was an absolute nightmare and the base still wasn’t set by the time I decided enough was enough. Once the mould had been turned out of it’s container (or wrestled out in my case) a craft knife was useful for removing excess rubber so the model could be easily removed.
I then put in the name so facing the correct way round as per sketch in part one. It was then part filled with resin to hold acetate down.
Once it had part cured, I could then fill it to the top and leave to cure fully.
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