lime mortar with perlite part 1

Yesteday I used the leftover mortar from rebricking the Kerr oven to make a small test brick with perlite.   

The mortar formula

10 : 6 : 2 : 3 – Silica Flour, Native Clay, Portland cement, and Lime.  

I did not measure the perlite.   Mostly I want to see how this sets in the presence of water.  In retrospect I should have weighed the ingredients and the perlite then worked out the ratio.

"Baby its cold outside"  Well maybe too cold for a little sample to set properly.  So I could not use my defunct chest freezer and water logged bath towels as per usual.

Shortly after it started to firm up I added 3 layers of paper towels.   This was not enough and it looked to be a bit short on water so I increased the layers to 6.  It is covered with plastic.  


Current thinking is to use a refractory similar to this for my first electric oven.   That is if this sample works out and I determine a good perlite ratio.

I am not about to try this on the first oven but it would be interesting to makeup 2 batches of refractory.   Have the second batch higher in lime and use it as the top layer which would end  up on the inside of the oven making for a better hot face.

I am thinking about putting a heater in the defunct chest freezer I use to water cure this stuff.   Was thinking about going fancy and maybe some day I will but in the short run I am going to try a submersible aquarium heater.

It is hard to keep the samples wet in the house using the paper towels.   Twice now I have come close to crossed the line where the concrete hydration will stop.   Need to dump the aquarium heater into the freezer tomorrow and see how it does overnight.