Step 5: Foaming gelatin
Place a puck of the prepared gelatin into your plastic jug and gently re-heat it in the microwave until it becomes liquid. DON'T LET IT BOIL!
Give it a stir with a coffee stick to make sure it is nicely mixed. Then add two or three drops of washing up liquid to the jug.
Get your small electric whisk and starting on the lowest speed begin whisking the mixture. Once it has started to take air you can increase the speed. You want masses of tiny uniform bubbles. I whisked mine for around ten minutes until it had taken on about 3 times it's original size.
Put the jug in the freezer for four hours. Then pull out the large plug of foamed gelatin. It is very much softer and more pliable than the standard mix and will make really lightweight masks and prosthetics.