Now we get to the good stuff - Weathering is the Great Equalizer

I've boiled down my efforts to metallic coatings in non-toxic casting materials and although I have succeeded in the short run of making the initial laminate I have reservations about the long term product and went back to researching actual products made to do this. Lo and behold there is a modified mixture of Hydrocal plaster that works as a kit with Mojo and Voodoo to make thin walled sculptures and faux metal castings that can exist in weathered conditions. The magic chemical hybrid plaster cement is called Forton MG.

Read More here:

http://www.artmolds.com/gateway/technique/forton_1.htm

FMG consists of a gypsum plaster modified (hence the abbreviation M.G., for Modified Gypsum) by the addition of plastics and fiberglass. The system involves mixing precise amounts of several products, including Hydrocal FGR-95 from US Gypsum or alternatively, Densite HS from Geogia Pacific (both are gypsum-based cements); dry melamine resin powder; a hardener; a liquid polymer called Forton VF-812, and; fiberglass. These various ingredients are the base to which aggregates, colorants and metallic powders may be added; in which the latter, though somewhat pricey, simulates the look and feel of metal.



and here:

http://www.douglasandsturgess.com/mm5/merchant.mvc?Screen=PROD&Store_Code=DAS&Product_Code=SC-1245&Category_Code=

If you've been frustrated by trying to put a plaster or gypsum cement sculpture outside only to find that it is slowly dissolving away, then perhaps you should look at Forton MG or Matrix G. Essentially enhancement systems for FGR-95, (see plasters and gypsum cements) these materials not only allow you to use FGR-95 outside, but also will enable you to create sculptures that can look like metal or stone at an economical price with a material that is relatively easy to use. The beauty of these products is that they do not need to be cast solid, but may be cast or laminated hollow with glass fiber reinforcement to create something that is light weight as well. Oh sure, you say, I can do that with cement or fiberglass, which may be true to a certain extent, but try to obtain the fine surface with cement, or avoid the sticky mess with polyester and fiberglass. It can't be done. With the Forton MG/Matrix G systems, we have a go-between material that gives you the best of both worlds. Available in three different sized kits.