Introduction: Resin Casting an Alien Army Using Tinting Pigments

About: With a love for making and creating things - and I'm lucky enough to do it for my job and as a hobby! I put together Instructables for all the projects I create as part of my job!

This project was my first step into the moulding and casting world and came about as I made a cute little green Alien from modelling clay and my kids loved it and wanted one each and wanted them in different colours - so I made a mould and cast a little alien army!

I used a resin casting kit which included everything I needed to complete this project and a few essentials from my craft box.

Step 1: Original Alien


Modelling Clay to make the original

Silicone Rubber and Catalyst

Fast Casting Polyurethane Resin

Tinting Pigments

Mixing Pots and Sticks


Something to make a container - I used Signboard

Cutting Board, Craft Knife, Ruler, Pen, Glue Gun, Scales

Abrasive paper & Sanding Block to finish the base if required

Prepare the work area - cover work surface and wear protective clothing.

Step 2: Creating the Mould Box

  1. First I measured the original modelling clay alien (height/width/depth) and created a container to fit around the alien snugly.
  2. Then I made a little base for the alien to sit on in the box from wax and this also stuck the alien down to the base.

Step 3: Making the Mould

  1. Next I weighed out and mixed the silicone and catalyst until it was all the same grey colour.
  2. Then I poured it into the container to cover the alien by just over 5mm and left it to cure (as per the manufacturers instructions) which can be found here.
  3. When it was cured I removed the container and wax and popped the alien out of the mould.
  • Silicone needs to be mixed steadily and thoroughly to make sure you don't put in unnecessary air bubbles and to ensure all the catalyst is mixed in properly so the mould will set properly.

Step 4: Casting the Alien

  1. Then I weighed out equal parts of the fast cast resin from my kit and mixed it together.
  2. It's so fast curing you have to work really quickly - I got caught out the first time with a half poured alien!
  3. I always tip and tap the mould to make sure the resin is getting into all the hard to reach areas like the aliens eyes - it pushes out the air too as I did cast a couple with air bubbles.
  4. Then I left the resin to cure - this resin takes less than 30 minutes, so I cast lots one after the other.

Step 5: Aliens, Aliens, Aliens

  1. When the resin had cured I demoulded it and checked the mould was clean ready for the next casting.
  2. Then I experimented with the tinting pigments - the set I used has 10 colours so I cast the full colour ones with around 30 drops of pigment which sounds like a lot but it hardly made a dent in the bottle.
  3. It's best to mix the pigment into Part A of the resin before adding Part B as it gives you more time.
  4. I also experimented with different amounts of tinting pigment of the same colour as you can see from the picture of the green aliens going from 5 drops which achieved a pale minty green through 10 drops/ 20 drops / 30 drops and 50 drops which is the deepest forest green.

I was so pleased with my little army of aliens and the kids love them - I think it would be a great way to reproduce your child's art work in 3D if they have a great drawing you could use for inspiration - the more simple the shape the easier it is to reproduce and they could have their own unique, limited edition figure to play with! (or a little army!)


Once I had created the mould - Each alien took me around 25-30 minutes - sometimes you need to tidy up the base with a bit of abrasive paper.

Please see the video from the project with lots of other casting examples too!

Resin Casting Starter Kit from Easy Composites

Translucent Tinting Pigments from Easy Composites

FIMO modelling clay from Hobbycraft