Blue Stuff, Mold Making

There is cool mold making material called Blue Stuff.  You use it to make molds and then press green stuff into it.  It is a two part mix and only takes 1 1/2 minutes to harden.  The Blue Stuff looks great for making quick molds for conversions like symbols, weapons or whatever.  I haven't tried it, but it does look promising.  I think it is probably better suited for half molds rather than full molds.