Oyumaru ,Blue Stuff, Instamorph this stuff is great!

[Andrew Gorman]

I was thinking of using the exhaust from a partial Rareplanes Douglas O-43 when I remembered I had some Blue Stuff mold compound that had been sitting around for years.  First time I used it and it worked great! I put the piece to be copied on a flat surface, got the thermoplastic good and hot and pressed it down hard with another flat surface parallel to the lower, and when cool, the master popped right out.  I made some with epoxy putty smashed into the mold and more with Alumilite liquid resin. This worked MUCH better then previous attempts with hot glue and bondo/bog.  And it doesn't smell bad.  No mold release required! For low relief bits I'm so happy with the results I ordered more generic thermoplastic mold compound.  I'll try some compressor faces and experiment with deeper profile bits like a nacelle and radiator face later. This material is cheap, and if I could make it work, easy to use, Generic search term is "thermoplastic mold material", brand names in the thread title.

[kerick]

Sounds good! Another useful tool.

[Andrew Gorman]

For one sided molds it certainly beats expensive urethane, a vacuum chamber and a pressure pot!  I have those, but have to dig them out and  set them up which is time consuming for a few parts.   The bits in the picture I did in the kitchen and no one in the house noticed. I'll try some more with hardware store epoxy, which is as cheap and quick as you can get.  Wheel halves, instrument panels, spat halves, anything with a flat back could work.  I was impressed that there were no bubbles in the liquid resin, but these were a thin application.  The epoxy putty casts were noticeably, but only a little rougher in texture. I got at least two pulls from each blue stuff mold with no degradation in finish which I didn't expect, thinking these would be one time use only. More news as it happens...