This looks like a knife forge, doesn't it?
First things first, I needed to cut a hole in the side for my burner.
Right about there looks pretty good. I used a length of 3 inch pvc for my chamber. The mailbox is roughly 20" deep.
I couldn't find the chuck for the drill, so I used an old hand drill. Found a 1/4" bit and used tin snips to make a relatively round hole big enough for the burner tube to fit in.
Same thing on the back side. I cleaned it up a bit after this pic was taken, but neglected to get a photo of it.
This is the first tub of refractory cement I used. Mixed it up well and added enough water to make it a consistency close to pudding. This stuff is rated for temps up to 3000F.
I read that the proper mixture is 4 parts perlite to 1 part cement. This is what it looked like mixed together.
I quickly ditched the tree branch in favor of an old broom handle to tamp the mixture. I did this between ever layer of refractory mix.
I quickly realized that I didn't have enough refractory cement, so I made a quick trip to the farm store to get a couple more tubs. When I opened it up I had lot more liquid separated from the medium and was much darker in color and softer in texture. Although they are the same brand and everything, they were bought from different stores, so we will see how it holds up.
This is it looks like now. Going to let it set up over night and yank the plastic out tomorrow.
After it sets up for a day or two I will mix up some more refractory cement and line the chamber and ends with it. I may have to put a couple inches of the perlite mix at the backside of the chamber so it doesn't melt it.
So far I have used about a gallon of refractory cement and roughly 4 gallons (2 bags) worth of perlite.