Sure, you can always create a press mold using some Green Stuff. One the mold is created (and the Green Stuff is fully cured), with a dab of oil you can use fresh Green Stuff to press into the mold to create some copies. This presents with only a couple of issues. First, you end up using a lot of green stuff and, once the press mold is created, you obviously can't re-purpose this Green Stuff. This isn't a problem is you see yourself making multiple copies of something but if you aren't, you could be using a fair bit of it and it could be costly overtime if you are creating multiple, different molds. This links to the second point -- Green Stuff while not overly expense, isn't cheap either (I can't reinforce the need to shop around here).
A year or so ago, I came across 'Instant Mold' and I finally had a chance to try it and test it out some. The stuff is pretty amazing and offers several advantages over using Green Stuff to create press molds:
- It's cheap. I bought my pack for about $12 - $14 at my FLGS
- It's quick. It takes minutes to create a press mold from something.
- It doesn't stick. It doesn't stick to surfaces (the original item or the copy you are making)
- It is reusable. That's right. Once done you can re-use the material to create new molds
The package contained six small bars of the stuff and the feel was something akin to a plastic. How to use them was simple enough. Boil some water and drop some in for two minutes. The heat is what makes the material malleable and it hardens up again when cool. While you wait, you may want to start thinking about getting the Green Stuff ready and whatever piece you need to create the press mold from. Keep in mind to use implements to pull the Instant Mold out of the water since the water will still be hot.
But what about whole objects?
It's still possible to do and the best way to go about it is to use enough material to fold over a bit and effectively sealing it. Once that is done and it has hardened some, you will need to cut it back out along a seem to leave you with two halves. You can use these halves to even copy an entire model though pieces like bits would be a bit more practical IMO.
When you are done and satisfied with your copies, simply put the pieces in boiling water for another couple minutes to reuse and reshape in order to create a new mold.
Well worth the investment given the re-usability of the stuff. Finding Instant Mold could be a bit tricky but well worth the hunt. CoolMiniOrNot has it online HERE and I saw some through a third party retailer on Amazon, HERE.