Thursday, November 13, 2014

20 minute moulds

 Whenever I’m brainstorming for new ideas, it seems that I usually need to make a mould. Being incredibly impatient, the thought of getting out plaster, mixing and waiting days for it to dry really doesn’t appeal to me. I’ll do it, but only if I can’t find a quicker way of getting the result I want. 

In my mould collection I have loads of rtv silicon moulds, looking for some seasonal ideas. I pulled out one full of snowflakes. It has some lovely designs, but they are so detailed and close together, it’s difficult to press the clay in and get a good impression. I also wanted to be able to stamp the design so that a cavity was left in the clay rather than a raised impression. This way if I used a coloured transparent glaze, it would pool in the recess and show the pattern.

I needed to make a reverse mould. If you want to try this yourself, you will need some rapid set resin, scales or measuring cups, a wooden stirrer, nitrile gloves (resin can melt vinyl or latex gloves), and an empty syringe. 

To start, make sure your mould is clean and dry. This one is made from silicon. This technique might work with other types of mould, but do a test on the edge first, there’s a chance that the resin will stick and ruin it.

Put your gloves on and measure the resin following the instructions. Mine is 50/50 so I added equal amounts in weight, then stirred with the wooden lollipop stick. You need to make sure you do this gently but thoroughly so that both parts are well combined, but you don’t add any air bubbles. You also need to be fairly quick. The resin has a 5 minute pot time and after this will start to cure. For small projects like this one, I usually only mix about 10 grams at a time.

Fill the syringe with the mixed resin and put a couple of drops in to the mould. Using the wooden stirrer, poke the resin in to all of the gaps in the cavity and then continue to fill until the resin covers the whole of the pattern. 

In a couple of minutes, the resin will start to change colour as it cures. 

After 15 minutes, they are ready to remove.

You can use them straight away. Just roll out some clay and stamp them on. If you find them a bit fiddly to use like this, you can make a handle from a cork and glue the resin casting on to the end.
I'm going to make these into individual moulds that I can use more easily. To do this, I've pressed them in to polymer clay and baked them. I now have an inny and an outy design for each snowflake.

There would have been a picture of the finished fired and glazed charms here, but due to an unfortunate incident with my cat being accidentally locked in the studio overnight, I’m afraid I have nothing to show… they would have been lovely!


  1. Cats are wonderful creatures, but they sure can cause a few problems now and again.

  2. I must try this it seems much quicker than making clay stamps. Thank you, and I hope you get the cat and studio back to normal soon.

  3. Thanx for sharing Caroline. I enjoyed this post.

  4. Thanks Caroline. So far I've been a miserable failure in the mold department, Perhaps I'll do better with this method.


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