Saturday, July 21, 2012

Vermiculite Concrete Gate 1

Armature made from fence posts with gate corners, extruded polystyrine sheathing. metal lathe, and chicken wire.

Using two parts vermiculite, one part builder's lime, one part Portland cement.

Hanging plaque made with similar mixture over Styrofoam and chicken wire.

Friday, July 13, 2012

Vermiculite concrete experiment

Working toward re-making the garden gate, which was an earlier attempt at faux wood using papercrete. The gate hangs on a fence post, so weight is a big consideration. That first effort was made of vermiculite, cellulose insulation, and cement. This new mix is two parts vermiculite, one part cement, and one quarter part builder’s lime. I started with one part water, but the vermiculite seemed to absorb a lot, and I had to add water was I worked. I made the armature for this small experiment out of  Styrofoam insulation and chicken wire. It will be a sort of hanging plaque, but I am more interested in seeing if the mix, sans paper, will work for the gate, and how heavy the finished product will be.
 The vermiculite mix handled almost as well at that made with sand. It was coarser, but not as much as papercrete, and I could add more details than with papercrete. 

Friday, July 6, 2012

I was out early yesterday morning to try and beat the South Carolina heat but, I swear, it warmed up too quickly. 
I experimented, substituting builder’s lime for joint compound: two parts sand, one part cement, one half part builder’s lime. No paper. Using a two pound coffee can for measuring and mixing the dry ingredients in a five gallon bucket, then hand mixing small portions with water in another bucket to make small batches. Very nice, smooth, clay-like feel to this mix. Sticks nicely. I was able to sculpt a little with it, but mostly used it as plaster. I am interested in deleting cellulose insulation in a mix because I want to try to add finer detail in future work. It seems to be curing nicely despite the heat.  The bottom photo shows the section covered with this mix.
The most difficult aspect of mixing this mortar involves water. It is so easy to mix in too much water. It's best when the mix is damp and crumbly. I found that making sure I had a bit of dry mix left  was the key. Then I could add some dry mix to a batch I'd made too wet..
With the mix damp and crumbly, I can dip my hand in water and work a handful iinto what feels like a ball of clay.