compatable resins for alginate

[Robobuild]

Hey guys...

Looking around the SM archives, I cam across a report where the modeler needed to make some extra parts, but didn't want to go the rout of making RTV mounds for just three pieces. He decided to used Alginate, the same stuff dentist use.

I saw the "genius" of this method, and has some alginate lying around. I quickly threw in some small parts I need to replicate, and made the moulds. Once ready, I poured in my two part resin , and to my surprise, the liquid started to bubble all over the place.

In my enthusiasm, I forgot that resin usually hates being mixed with water. The water in the alginate was setting it off.

So, my question is, does anyone know how to make casts using alginate? I don't want to use plaster, as I was hoping to use these pieces for a scratch-build. Cost is also a factor, cause it it works out that the resin is as expensive as RTV, it brings the whole process back to zero...

Any ideas?

-Robobuild

[Owen E Oulton]

Urethane resins definitely don't like water. I'm not sure about polyesters, but I suspect they'd have the same problem, plus the toxic smell. Have you tried an epoxy? There are several pourable casting epoxies available.

[USSARCADIA]

I made a mold of a Happy Meal toy to make a ship with an alginate mold and some polyester "fiberglass resin" from Home Despot. It turned out pretty good with no stickyness:

http://img.photobucket.com/albums/v72/u ... G_0238.jpg