How to use Casting Resin and Moulding Paste in 5 simple steps

Sometimes you want a particular element for a piece you’re working on and you can’t quite find what you’re looking for in the shops. Luckily, if you have an object that’s similar, you can make a mould and use casting resin to make a copy!

Here are my five simple steps, using Siligum moulding paste and EasyCast casting resin.

Step 1

Siligum moulding paste

Siligum comes in two pots – one blue, one white.

On their own, they don’t do anything, but mixed together they will form a flexible compound that you can press things into to form a reusable mould.

Step 2

Take two lumps from each pot that are the same size.

Mix them by kneading them, and rolling them between your hands for around a minute.

It can be a little tough at first but persevere.

Step 3

When the ball has become a solid colour, it’s ready to use.

Beware, it sets in five minutes! Don’t hang about at this point.

Press the item you want to make a cast of into the paste. This is a copper blank of a cog, but I also tried taking an impression of a spider ring which really didn’t work as it went straight through the bottom of the mould.

Step 4

Here is the mould minus the cog blank!

Now you need to mix the resin. Take equal parts resin and hardener and mix with a wooden stirrer – I used a small measuring cup I bought specifically for this purpose, and a cocktail stick. After two minutes of thorough mixing, pour into a second container and mix using a fresh stick.

After a minute, you can add any colourants – I used black mica powder but I’ve also used loose eyeshadow powder too. I added it to the mould by adding droplets from the cocktail stick until the mould was full.

Step 5

Leave the resin to cure for 72 hours – not good if you’re impatient like me!

Be aware that sometimes bubbles can form – simply run hot air from a hair dryer across the mould until the bubbles rise to the surface and burst.

Some resins and moulding pastes need a release agent to get the cast object free but I found using my products that this wasn’t the case. I simply popped the resin object out of the mould.


Here is my black resin cog close up.

Be careful when you’re casting – ensure that you use the exact same amount of the resin and the hardening agent, and mix thoroughly. Always scrape from the sides of the container and use a second cup to ensure thorough mixing.

Don’t reuse the cups – I bought a supply of about fifty! Same with the sticks. You don’t want to risk contaminating the next batch.

I bought all of my supplies from Metal Clay – Siligum Moulding Compound; EasyCast Clear Casting Resin; small mixing cups; a 19mm cog blank; and the colourant was Pearl-Ex powder in carbon black.

Have you ever used resin or moulding paste?

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