So, it's been a while since I posted something educational.
How to cast your own gems
You will need:
- Liquid Rubber Latex (Air drying)
- Clear Casting Resin plus hardener/Catalyst
- Colouring Agent
- Small square container whose edges are larger than the Pringles tube (8-10cm tupperware box is ideal)
- Disposable cup and stirring stick
- The object you're going to make a copy of
Steps in GREEN
are OPTIONAL. You do NOT need to follow them, although you can if you wish.
1. Find a work area which is flat and level, and free from pets/small children. Assemble all ingredients.
2. Take a deep sniff of the latex, it smells roughly like 12 used condoms, without the fond memories.
You can apply the latex in one of two ways - brushing or dipping.
3A. Brushing: Take a small, fine brush and simply paint the entire object in latex, thin enough so that it doesn't drip. Repeat as many times as you need, depending on the thickness of the coats, probably 8-10 times to get a nice mold. Obviously let it dry between coats, just like paint.
3B. Follow manufacturers instructions and simply leave the brush in water between coats instead of cleaning it properly. Rage in frustration as it destroys a nice expensive Citadel wash brush.
4. Dipping. Literally pick up the object and dip it in the latex. Remove it and pop any air bubbles. Re-dip again immediately, then leave to dry. Repeat as often as necessary. Make extra sure the latex is dry before dipping again - you know it's cured when it's completely transparant and not-white.
5. Alternatively, and particularly well suited to flat backed gems, you can place the master copy in a small tupperware box, flat side down, and pour the resin over it. Do it in depths of a millimeter or two at a time, letting each layer dry fully before doing the next one.
6. Eventually, you'll have a workable mold of your object, which is a minimum of 2mm or so thick. If you're planning for it to hold it's detail well, you probably want to go for about double that to reduce distortion.
7. Remove the master item. Bask in your own magnificence.
8. Now you need to set up the mold ready to fill with your casting resin. It needs to be flat side facing up, and level. Because a flat backed gem shape will obviously distort when placed flat side up on a table, you need some way of suspending it with no weight on the shape itself. Enter the Pringle tube. Cut it to a manageable size (eat the Pringles first, idiot)
and then make sure it sits level on the table.
9A. Pour an appropriate amount of resin into the cup. Always use slightly more than you think you'll need, because you'll never get the colour right twice, and mixing when it's already in the mold is a pain in the ass.
9B. Marvel in astonishment as you read the instructions, and realise that they want you to use 2-3 millilitres of hardener with 100 grams of resin while using no more than 5% colour with no way of measuring any of it. Who the fuck measures liquid in grams?
10A. Add about a half teaspoon of hardener for small gems, a full teaspoon for large ones. Literally dip your stirring stick in the colour to a depth of about a centimeter and use only what sticks to the stick. Do not pour colour into the resin.
10B. Get overenthusiastic and pour about a teaspoon of colour into the resin, then have to bin the whole thing when it refuses to cure and leaves a sticky hard-to-clean mess in your nice new latex mold.
11. Stir well, without generating air bubbles if possible. Pour into your latex mold. Curse as you knock the mold, spilling all the resin over your workspace. Frantically scrape it back into the cup and use it again before cleaning up your fathers tool bench.
12. If using a POLYESTER RESIN wait for it to get tacky and mostly solid (spend the time sitting around making jokes about what else you could mold out of latex)
. Then place some clingfilm or plastic (I cut up a plastic bag) on the flat back, removing as many air bubbles as possible. This will hopefully prevent the back of the gem from curing "sticky".
Pop it out after 24 hours (don't get impatient!) and admire. I'll tell you how to back them to make them shiny once I'm done doing it myself and making all the mistakes.