There’s been a lot of interesting discussion on a previous blog post No Spaces Between Stones about building a model to show how ancient structures were made with geopolymer. To my knowledge this would be the first experiment of its kind. LeRoy Martinez, one of our readers, wants to build a small stone to test this theory. LeRoy has a background in mold making and believes he can pull this off using primarily local materials. Some of his comments are pasted below.
“I wish I had known of Davidovitz’s theory before I visited Machu Picchu. I would have certainly spent more time checking the stone texture and fit. I have a mold making background so I can see how some of these could have been cast in place.
Picture this: First they made a 4 sided box from wood and made it large enough so a person can get inside of it. There is no top or bottom. Then he covers the inside of the box with clay and he can be as artistic as he wants. He is making the reverse side of the rock. He only has to make the 4 sides of the stone. The bottom can be flat and the top is open. Then he will press decomposed granite or whatever stone they want to reproduce into the clay. When he has finished he climbs out of the box (mold) and laborers can make multiple pours of the decomposed granite and sodium carbonate solution being sure to coat all of the clay substrate that has the granite surface embedded in it. When it has cured the box (mold) is removed and the stone is finished and in place. All that remains to be done is to wash and brush off the clay.
The decomposed granite that was pressed into the soft wet clay has become the outside surface of the stone. It will provide the texture because it is decomposed granite reconstituted.
The mold can then be set on top of that stone and the procedure done all over again. No two stones will be the same because the sculptor is good at his trade and has his reputation at stake.”