Friday, September 17, 2010

Wood-Fired Oven ~ Oven Floor

We took a break for the entire month of June; I was busy gallivanting in Europe so we installed a makeshift tent to protect us, and the oven, from the harsh sun of July!
We did a mix of fireclay from Tucker's Pottery and some brick sand. We had to screen the sand to make sure it was free of small stones and to get rid of some weeds which grew in it over the past year. What should I expect: I had the sand delivered a year ago.....
The layer is rather thin and its purpose is to level the bricks; it's not really acting as a glue.
Once all the bricks were placed properly, I realized I miscalculated the void needed for the ash slot. Because I use 10" wide cement blocks to do the base, it made the hearth slab slightly narrower so I couldn't make the oven floor as wide as Alan Scott's plans were depicting. Not a real problem, we'll reshape the ash slot at a later step.
I selected the firebricks from Alphatherm and they are of medium duty, 9 X 4 1/2 X 2 1/2". Since then, I found some locally but they are much smaller; it would have made the project much longer: more bricks to level!

Thursday, September 16, 2010

Wood-Fired Oven ~ Hearth Slab

We had precut the 5/8" rebars so that we wouldn't waste any handling time. We positioned them as soon as the heartn insulation was leveled and tied them with a small wire and we are ready to pour the slab!
All around is a 1" piece of wood that will create an air gap necessary for any expansion of the hearth slab during heating. This wood frame also provided the height needed, 3 1/2" thick for the hearth slab.
The slab is made of Lite Kastite refractory concrete supplied by Alphatherm in Toronto. Another alternative would have been to use a mix of Portland and lime but since Jim Wills suggested the Kastite for a stronger slad more resistent to heat cycle, I went with the expert's choice!
If I'm going to go into the trouble and time to build this bread oven, I might as well not skimp too much on the materials. This oven will still be standing much longer after I'm gone!!!
And by the way, this was done on May 26 of this year. My dad visited often this summer allowing us to accomplish a lotvon the built. As I'm writting this post, I'm preparing for his visit this coming week-end; I have great hopes to convince him to visit one more time before the winter and to finish the oven.......

Wednesday, September 15, 2010

Wood-Fired Oven ~ Hearth Insulation

On the plywood support, we poured a 5:1 mix of vermiculite and Portland cement to have a 2" thick layer. This will be the first layer of insulation for the suspended hearth slab. After a few months of use, we will insulate further from the bottom. At the far side, you can see the void for the ash slot. We had to work fast to pour the hearth slab on top the same day to ensure proper bonding between the 2 layers. We also poked a few galvanized nails at a 45 degree angle in the vermiculite layer to increase the bond.
Funny how it looks like my dad is working alone......