Cornstarch and gypsum-based models

DeltaVee · Post by **DeltaVee** » Fri Jun 04, 2010 11:03 am

I guess this could be in 'Finishing" but I thought someone here might know more about the basic materials. I'm painting a small Mars base diorama provided to me by another party. It's supposedly been stereolithographed out of cornstarch and gypsum mixed with water. It's not been sealed with anything and feels rather porous. I'm unfamiliar with the medium. But cornstarch and plaster dust suggests to me that I need to seal it with Future or polyurethane and finish with acrylics - avoid enamel paints and thinners. I'm also curious about how it sands, drills, and glues. Anyone familiar with this medium and now to treat it?

Post by **TER-OR** » Fri Jun 04, 2010 3:57 pm

Others please jump in, but I'd soak Future into the piece. That acrylic should do a good job holding things together. It cures more quickly than something like Envirotex.

You'll need to be careful machining holes into it, though. Definitely figure out mechanical means of fastening.

DeltaVee · Post by **DeltaVee** » Fri Jun 04, 2010 4:15 pm

Thanks. What's Environtex? Brand name for polyurethane? As far as drilling, I was just pondering how to attach to a plaque to make it look a little more 'finished.'

Post by **TER-OR** » Fri Jun 11, 2010 10:46 pm

http://www.michaels.com/art/online/disp ... channelid=

It's an epoxy resin, mostly for finishing tabletops etc, embedding chunks and stuff in a frame etc. It's pretty thin to start with, but I don't think it will work all that better than Future for your purpose, which will seep into porous materials very well.

DeltaVee · Post by **DeltaVee** » Sat Jun 12, 2010 11:40 am

Thanks. Since my first query, a friend recommended an acrylic automotive primer. We tested it and when it didnt' discolve the model, we sprayed it and it worked great. Thanks!