Here's a test from me as well: (originally posted over at WAMP)
Ok guys, I bought some InstantMold from the Cmon-shop a while ago and when I saw this discussion I decided to make a test run. I already experimented loosely with making a print of a space marine helm just to see how it catches the detail and all in all I'm impressed. I wouldn't use it for full 3D-moulds but for small, quick detailing it's worth its weight in gold.
Here's my 2 cents along with pictures!
I decided to make a mould of the old GW skeleton shield skull emblem:
It's got enough detail to show how the mould works without making the pics look busy.
So, I cut out a piece of the instantmold, just a bit larger than the object I'm going to mould. It turned out that the piece was a lot larger than I expected but it's a bit like measuring green stuff, take about half of what you think you'll need and then you can probably split that in two as well.
It's very easy to cut as long as you have a sharp knife, its rubbery consistency makes it hard to cut through at first but once you're through the surface it cuts easily:
it states on the package that you should heat water to 170 Fahrenheit, that's roughly 77 Celsius. Now, you can heat it to boiling status as well without any visible effect on the material other than that it gets more difficult to handle if you have sensitive hands. at roughly 80 celsius it is still possible to pick it up with your hands if you are quick about it, it's not hot enough for you to get burned but it will hurt if you keep your hand in there for more than a second or two.
At this temperature it is very knead-able and is rather fun to play with, and if you play with it a few times you can easily feel at which temperature you need to tuck it into the bath again and where you can still use it for moulding, it cools down quite quickly once outside the water. Just be very careful not to get any water into the mould while kneading, it doesn't blend together but it does create pockets that can and will ruin the mould once you press it.
Once it has set completely it handles and feels a lot like silicone, it is extremely bendy and it doesn't break from any kind of handling unless there's a crack in it.
Here I just simply laid the skull against the table and pressed the instantmould around it just like if making a GS mould or similar, making sure I press it evenly from all directions so that the subject doesn't move and distort the mould.
After it has completely set(this takes perhaps one or two minutes) I remove the skull from the now finished mould:
As you can see the material picks up detail wonderfully and there is almost no air pockets to speak of, a really lovely indent. Sadly you can see that I accidentally moved the subject while pressing so the forehead of the skull is slightly elongated but this is just another proof that the instantmould does hold detail very well.
After this I just knead a bit of green stuff together and press it in, being careful not to let the stuff stick to my fingers since it definitely does
NOT stick to the mould.
Now I took the closest hard, flat thing I could find and pressed the mould against it to make the subject stick to that surface and ensure an even pressure when removing the mould.
With Green stuff this process is completely awesome since it allows you to make tons of copies with just one mould since the green stuff doesn't stick to it whatsoever and you don't need to wait for it to cure to be able to remove it from the mould without risking warping.
I did make a copy using FIMO as well, this did stick a bit more to the InstaMold but not enough to cause any considerable grief, it just took a few seconds longer to remove the mould.
Hope this helps!
Cheers!