Guide : A Simple One Part Mold

In this tutorial I used Resin Plaster to cast the figures, this can be done in the same manner as the two part mold guide with polyurethane resin.

This is the mold box from above. I worked out what volume the tub of Silicone would fill as I was going to use all the silicone and catalyst in one go I thought Id just make one big mold rather than two seperate molds for the head and the bodies. So in theory the silicone should completely fill this mold when its completely poured in.

I then lined the inside of the MDF mold with foil, I prefer to do it this way as it gives a easy release to the silicone when you goto take the box apart, its not porous at all, so the silicone has nothing to attach itself to. You can of course make your mould out of LEGO, this is what I normally do but I didnt have enough for this size box. Using the LEGO is super simple and the best way to go about it, you can buy bags of bricks on EBAY.

Here is the mold all put together, I put a thin layer of card on the bottom, as it provided a super flat surface to stand the pieces on, Foil has a tendancy to wrinkle when attached using the photo mount and doesnt leave a nice flat surface. I also used some masking tape around the inside edges to seal off any gaps there may have been,of course with LEGO you dont need to do any of this as it self seals, all you need is a nice flatsurface to stand
the LEGO mold on.

Here are a couple of photos showing the pieces stood in the mold. Dont pack them together to tight, always leave a good gap

I always like to use a pouring jug to mix the silicone in, it makes it a ton easier to pour accurately rather than mixing it in the pot it comes in.

Pour the silicone into the jug and add all of the catalyst (if you are using it all in one go) you could do half/half if you wanted to use a smaller amount.

Mix the catalyst into the silicone until it completely blends in, and you end up with a light blue colour.

Once you have poured it all in give it a few light taps on the sides to release any bubbles of air you may have captured in there. Silicone is pretty good for not holding that many bubbles, so it doesnt cause that much trouble. Now leave it for 4 hours to set.

Here it is 4 hours later, the white marks on the top are just a few slight areas of the base silicone which didnt get completely mixed with the catalyst.

Now carefully peel off all surrounding walls, foil and tape and you end up with a big block of silicone, now its time to take off the bottom piece and reveal the mold.

This is what I use to make my figures, its Resin Plaster by Gedeo, I purchase it from a local shop, but it should be available in a ton of craft shops or online. Its like plaster of paris, but sets a lot tougher, it can chip if dropped from a height, but still takes a lot of abuse. The plaster itself is mixed with a 1 / 3 ratio, so for everyone set amount of water, you must add 3 amounts of plaster.

Here is a quick pic of my makeshift factory that I use when Im in the gallery. You can see my previous molds using Silicone on the left.

I use a kinder egg shell as above to measure out my portions. For this new mold, it will be about 2.5 scoops of water to 7.5 scoops of resin plaster.

Sprinkle the resin plaster over the water, then it leave to stand for one minute.

After 1 minute, mix it for another minute and you are ready to pour. If you have the mixture correct, it shouldnt be to runny, it should be the consistency of tomato soup.

I then pour the plaster into the mould, but dont completely fill up the body sections. Air is the enemy of somebody making molds, as it can cause chaos and ruin the finished figure. I use the thin end of a paintbrush and run it around in the mold, going down into the feet sections and making sure there aren’t any bubbles trapped down in there, then I top them up.

Also after 5 minutes just as the plaster begins to set and gets a bit thicker, I give it another mix with the brush handle as it gets out all the tiny bubbles of air out. Then, after it sets even more I get a little tiny squeegee and run it across the top of the mould to make it smooth (as above).