First off, let me say this is for your own use.
Don't copy parts for commercial reasons.
1: Fix your original parts (masters) firmly in a polythene or similar container. Not too big or you will waste moulding rubber.
Fix the parts down firmly using double sided tape. You don't want your masters floating to the top of the moulding rubber as it is setting.
2: Mix and then pour enough moulding rubber, taking care to make sure it goes into any little nooks and crannies. You don't want air bubbles as these will come out as a 'blob' in your final casting.
If you find you haven't mixed enough rubber, it's ok to mix more but try to get the same ratio of silicone to catalyst. Pour it into your still uncured mould.
3: Allow the mould to cure for 24 hours, then release it from the plastic container.
Carefully cut around the edge of the master using a knife blade. Don't cut deep - about 1-2mm is plenty.
Peel away the rubber you just cut free.
4: wiggle your master free of the rubber mould and then clean up the open edge of the mould with nail scissors.
5: Mix your resin and pour it slowly into the mould. Flex and twist the mould as you are pouring and also poke a cocktail stick into any fine details in the mould so as not to get air bubbles.
If you haven't mixed enough resin you MUST let the first layer harden before adding more.
6: Let the resin cure - about 5 - 10 minutes.
7: Pull your copied part from the mould. Bingo.
8: clean up and cut away any resin not wanted on your part.
You can see my intake fan casting had a thick base of resin. This was cut away with a razor saw.
Be VERY careful about resin dust. It's nasty stuff.
There are many moulding rubber and resin suppliers on the web.
I mustn't mention them here but PM me if you want more info.
Have fun...
roymattblack attached the following image(s):
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