adobe for sculpting

[lfry]

Years ago I used a recipe for adobe that included clay, cement, and acrylic admix that worked well, but I can't find it. Does anyone have a good concoction they've used?
Basically I'm looking for a material that can be modeled easily over an armature and can last outdoors. Concrete isn't great for modeling details.

[Andrew Werby]

I doubt that mixture would work in the way you describe. The clay will want to shrink against the armature and crack, and the weather would degrade it further. I doubt there would be much left after a couple of years of freeze/thaw exposure. Adobe structures depend on a roof to keep them from dissolving in the rain. Maybe it would last longer in the desert, though.

[raspero]

I had an adobe house for years. What Andrew says is right on. You need long overhangs on the roof, and you paint on a sealer at least once a year. I used an acrylic sealer. Out in the sticks they use burro shit and water.

The guys who made the bricks used a clay/sand mix, basically the same thing they use for fired brick.

We have been building some schoolhouses here using something we call Eco-block. It's dirt and cement mixed with a bit of water and rammed in a press. It seems to be pretty weather resistant.

Richard