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Showing posts from June 2, 2013


For the floor of the shelter I am building a kind of hypocaust system. I wanted to prefabricate some of the pillars because, as I know, bricks are much easier to join vertically than horizontally. I can make stacks of three bricks and then turn them upright once the mortar has cured. I realized once again the importance of having the right tools and equipment. I was using a scrap piece of MDF for the base, but it was very uneven when I placed it on the ground. I was cleaning up some of the mortar and I knocked over one stack...and the whole row fell like dominoes. 

After being rather angry for a couple of minutes I decided to make some proper tools and start again the day after.

I found a long board for the base, much stiffer than the sheet of MDF. I also made myself a guide so that I can line up one set of edges.

The board and guide.

I used clay again to support the first brick of the stack and to position it against the guide. Only the small ends of the bricks will be visible in the fin…

Dessert bricks

I have commented before that bricks and bread have much in common. Tiles are perhaps more like cake or dessert. I want to try some glazes on this clay so I made some test tiles. On some of them I painted a layer of earthenware slip, to make a lighter background. Hopefully the two clays are compatible. As they were drying on the board they looked very edible, like some sort of brownie.

Lime Putty

I've been considering the idea of using lime putty to finish the joints on the inside of the roof. This is for multiple reasons. 1) Lime-based substances are breathable, so if my joints on top aren't completely watertight (and I'm pretty sure I am fallible!) and some moisture gets past them, it can evaporate out through the lime.
2) A putty-like compound will be easier to work with on the ceiling. It is more likely to stick in place than a mortar. I will just have to wear safety glasses and be careful, though, because hydrated lime is extremely basic (pH of 12).
3) I've been curious about lime because up until the beginning of the 20th century all mortars were primarily lime-based. (See this post) As well, Internet research has yielded confusing information on the merits of hydrated vs. hydraulic lime. So far, I've determined that hydrated lime does not cure, it sets by absorbing carbon dioxide from the air. This process is slow because the chemical reaction is happe…