Mold Making Supplies... What do you use?


Im sure this question gets asked in one form or another probably twice a week around here. But I want to put a personal spin on it...
I want to cast some things. Actually more things that I can afford right now. Thats why I need the input of people around here that know so I dont waste money buying the wrong stuff or buying from a place that has high prices.
The main thing I want to cast is a few little widgets of things I have. One is a Star Trek Pin from the new JJ Abrams movies. I want to make some variations to the style and cast them. I want to do a 2 sided mold.
I also want to cast some plastic model parts and panels that I am using to build a custom Borg Cube. Think "Death Star" meets "Best Of Both World Cube".
And third and final I wanted to cast some tools, like a hammer and large pipe wrench to be used as a safe prop for hitting people with... I know that for these I am gonna probably need a polyurethane foam to cast.
My problem is that the options are endless. Not only does it seem that there are many companies to choose from. But there seems to be hundreds of different silicones and resins...
So now that Ive explained myself... What is a good silicone for Casting plastic pieces? And a good basic Plastic (resin) to go with it. And What is a good Eurethane Foam to use for making safe props? Also I was looking to use an alginate instead of clay for sinking the piece into for the first half of a mold. And finally, where can I get a good deal on say gallon sizes of these items?


Master Member
Where are you located? Price and types of product will vary from country to country.

Some things you need to consider when choosing a silicone for molding is how many casts do you want from the molds?

Most molding and casting materials have a listed 'shore' which is the hardness of the rubber.

I am in Australia and the stuff I am using now is called Vario-40. It has a shore hardness of A40. The stuff I was using before was called "PinkySil" and had a shore of A25, so a much softer silicone. I went for a harder silicone to (hopefully) get more life from my molds. The softer silicone started breaking up after 12 or so casts. The breaks varied from cracks to small pieces breaking away which each cast. Once a small crack or divot appears, the next cast has a lump or ridge, so not suited to my needs.

So far I have made about the same number of casts from these new molds and there is no sign of deterioration.

There are also fast set and slow set products.

The PinkySil pot life is about 2 min and the stuff sets in about 12 minutes, so no time to degas and as a result, you could trap small bubbles during the pour
The Vario-40 takes about 2.5 hours to cure, so with a workable pot life of 15min, time to can degas and pour bubble free molds.


I am located in Wisconsin, USA. I would like to be able to do a decent amount of casts from any given mold. Not in the 100's mind you. But I would be happy if I could get 10-20 pulls from a mold. Maybe 30. Any more than that and Ill just be making stuff that I will never use...
I do have a vacuum chamber for degassing the silicone before pouring too.


I have used smooth on and to be honest. The silicone seemed cheap. It was very flexible and I want to try a different brand. Probably a Platinum type.
I have watched a ton of videos on Youtube but every single video uses a different type and different brand. I just wanted peoples opinions on here as to which type they use and where the best (cheapest) place to buy it is...

Lord Magneto

Well-Known Member
If you have a hobby lobby close by you can buy a large kit from alumilite for about $40 I think after. 40% off coupon. It's a good place to start


Sr Member
Platinum cure silicones will cost more than Tin cure silicones typically. I use Smooth-On's products quite a bit and I like them. They have several different durometers with different qualities to suit your needs.
A local company here in California (that does mail order!) is Douglas and Sturgess. Their website is and they have several kinds of silicone that I like too. One of which is a decent cheap Tin based silicone called PurpleStuf. It doesn't have the tear strength and durability of better (more expensive) silicones, but if I am only planning on casting a few parts out of the mold, then it is more than adequate (which is what this one is designed for). They have better quality silicones too, and you get what you pay for. The better, more durable, more elastic, more archival silicones are gonna cost more.

Another tip: A light(!) spray of mold release before each casting will make your molds last a lot longer.


I do have a can of Mann "Ease Release 200" Mold Release. I guess I am asking who is the best place to buy from. I have heard of a place called Burman Industries that apparently sells to the hollywood crowd but their prices seem really high.
Or at least what is a decent price to shoot for for a standard silicone that will work well casting plastic pieces? I am looking to buy the gallon sizes and split it with a friend. I assume that I want a stiff/rigid silicone. Not a soft floppy kind.
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