I found this post online: [URL="http://scratchbuilt40k.blogspot.com/2012/02/instant-mold-how-to-use-it.html"]http://scratchbuilt40k.blogspot.com/2012/02/instant-mold-how-to-use-it.html[/URL]
According to it you can use resin if the pieces are thin enough.
I'm going to give it a try in another week or so.
You absolutely can. Not that I'm biased as the author of the article or anything like that
My blog Scratchbuilt 40k- http://scratchbuilt40k.blogspot.com/