Thursday, September 19, 2013

Patience is a Virtue: Mould Making

Caroline of Blueberri Beads so enjoyed writing for our readers, she's written another article for our wonderful AJE readers. Today she covers mold making. Enjoy!

I've had a busy week this week, all my kids are in school and I've had some time to make some plans and get organised. I did expect to be standing here after week 1 with armfuls of creations, but I seem to have just run around trying to do everything at once... I think I need a lesson in pacing myself!

So next week is going to be better, I have a plan of action and am working at things in stages. So I thought I'd share stage 1 of what I'm working on.

For my first project, I'm going to make a ceramic moon cabochon and set him in copper. So as I want to it to be repeatable, I first need to make a mould.

I have discovered a great way of making really sharp moulds using polymer clay and RTV moulding silicone which I'm going to share today.

I use Super Sculpey original to make my masters. Although I like to sculpt in clay, the polymer makes a much better mould as it's less porous and so far, has worked every time! Unless ceramic clay is glazed, the liquid silicon will stick to it and destroy the mould when you come to take out the master.

Here are the moon faces ready to make in to moulds.

The moulding compound I use is the same as the 2 part putty, but comes in liquid form. I didn't really get on with the 2 part putty and found it difficult to use around anything that wasn't flat. The liquid type is much more cost effective, so you can make a decent size mould that should last for a long time.

To hold the master and the moulding compound, you will need to make a container, I've found thick cardboard works really well. Make it into high sided boxes.

Roll a sausage of Blu-tak and stick it around the bottom edge of your master and stick it in the box. The blu-tak will stop the silicon from seeping underneath and keep your master from moving about.

Weigh and mix the 2 parts of the moulding compound in a cup taking care not to add too many bubbles. The type I'm using is condensation cure and has a working time of about 15 minutes so don't hang about too much! When the mixture is an even colour it's ready to pour.

Pour it into the mould in a slow stream, this helps to remove any bubbles that are there from the mixing.

When the mould is dry (I leave mine overnight) peel off the box and remove the master. You might need to trim it a bit with a scalpel blade to make sure your clay comes out easily, and that's it! To use with clay, I brush a bit of oil in to help it release.

Here's the clay when it's just come out of the mould,

And here they are after being trimmed and cleaned up, drying out ready for firing.

And after promising to be patient, I was in a rush and put these in to fire on Sunday and put the wrong program in, completely missing the slow ramp section of the firing. I opened to kiln a few hours later to lots of little exploded moons... Good job I have moulds!



  1. Thanks for sharing more useful tips Caroline - I use 2 part come and it's a horrendous price so I might just be giving this a go...

  2. Another wonderful post!! What is the name of the 2 part silicone liquid? I don't think I've ever heard of it. I do like the regular 2 part silicone compound I use but as you say for some things a liquid would be much better.

  3. Thanks ladies, I was actually looking for something more cost effective Lesley, I get worried using expensive stuff because I usually make a pigs ear of things on the first attempts!

    The silicone is called RTV silicone moulding rubber over here Kristi. This is condensation cure, which just means it will cure under normal conditions and is shore 28 which is the hardness. It sets as a quite stiff, but still flexible rubber.

  4. You are a patient soul! This is a tedious process. Nice work!

  5. Love the moon faces! I have visions of them in porcelain with PMC over... how bout that? Your process looks so clean and orderly! You should see me when I am doing plaster molds! All the same steps, and dust, and splatter...

    Sorry they didnt make it.

  6. What kind of jewelry are you going to make with those faces? In Calgary, jewellery like this would be a hit! Thanks for sharing all your lovely creations!

  7. Sounds like you and I have the same type working style, lol. Lord help us! Love the faces!

  8. I love it! I have a hard time eyeballing that 2 part mold compound (the solid, clay form) and it never quite cures correctly. This is COOL!!!

    Glad you have molds to make more moon faces :)

    You Rock Caroline!

  9. Thanks for all the lovely comments! :)

    I'm planning to make something up in copper to start with Jenny, I have silver, but I'm a bit of a scaredy cat at the moment, so I'm sticking with cheap and cheerful while I practise... and I don't usually work this tidily, if you could see out of the edges of the picture, it's a different story!

    I'm planning on setting these in bezels Anne, not quite sure what as yet, I tend to make things up as I go, but I'll share more when I decide :)

  10. Thanks for sharing your process. Its always fascinating to get a behind the scenes look at how things are created. Sorry the moons exploded. They looked cool.

  11. I've just clicked your link Anne, there is some fancy stuff in there! I hope I can get my work up to that standard, but I have a bit of a way to go yet!

  12. Thanks for sharing. I have considered making molds but never given it a go. It is encouraging to read your post. You give me hope that I just might be able to tackle the projects I have in mind. I'm curious about one thing, I would think you would fire the Sculpey clay first, then create the molds. No? It doesn't sound as if you this is the way you proceeded.

  13. Sorry Ema, yes, I should have said, the sculpey is fired before I make a mould from it.

  14. That is amazing!!! I can see why you llike using the liquid mold because each one came out perfect!

  15. Just found your page by accident — loving it!
    Interested in making a mold of a round marble for resin... so it would need to go all the way around.... advice? suggstions?

  16. where can you find the two-part liquid silicone in blue?


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