CHANGE OF PLANS

I started researching "stone" ovens on the internet (hey, why experiment when others had undoubtedly perfected oven building since man discovered fire).  First of all, from what I gathered, if one built a stone-walled oven, the high temperatures could heat up tiny pockets of water trapped within the stone leading to little "explosions" of steam that would pop shards of rock into the oven and potentially any food that was cooking (this is called "spalling"). So time to change plans.  Why not use BRICKS!!  Clay bricks are kiln dried and in general do not have this problem.  So the idea was now to build the actual oven out of brick and place it on the stone base.  And from my now voracious reading, I was "informed" that the bricks should be covered by insulation - this will hold the heat in the bricks after firing, allowing them to radiate the heat back into the oven for hours (even overnight).  Otherwise the bricks will get hot but radiate the heat outwards making the oven inefficient and very hot to touch...
OK, so my original plans are now  no darn good.  My stone shell will now have to be filled and the brick oven can be built on top...but I will need a much larger footprint as now the oven will be insulated.  No problem...

 I wandered 20 feet to the nearby Ouareau river and carried a whole

bunch of river rocks to the oven base and dumped them in.  I also enlarged the footprint of the base by using some concrete ("cinder") blocks that had been dumped at the local quarry.  I like this as it is free and, best of all, reuses discarded material (recycling!).   I knew this new wall was going to look ugly, but it is at the back of the oven and I envisioned that eventually it would be covered with a wood storage area (a little wood "shed"). 

 I covered the top of the stone filler layer with old broken hockey stick shafts (the new composite ones - very strong) that were also free and being reused instead of ending up at the dump.  A couple of rows of bricks were used to make sure I had a level base on which to build the actual oven.  Then the base of the oven needed insulating - I opted to use perlite.  Perlite is an amorphous volcanic glass that, after processing, makes a lightweight insulator that is also strong.  I mixed the perlite 10:1 with portland cement and dumped it on top of the hockey stick/rock base.  The perlite/cement mix is easy - dump 10 buckets of perlite in the wheelbarrow, add 1 bucket of  water, mix with a shovel for a few minutes, then use.

 Why the mask (below)?  Perlite dust is toxic!! Probably not as bad as asbestos, but not something you want to suck into your lungs.

 

GENESIS

I don't remember where exactly I got the idea from, but when you have the right space, cooking with wood just seems so natural - and tasty.  And cooking over an open fire was such a pain in the rear end - having to keep burning wood to get nice hot coals if you wanted to cook anything for a long period of time.  So I thought why not build a wood burning ovne? The advantages are numerous - from the stuff you can cook (breads, pizza, meat, beans, etc.), to the high temperatures that you can use safely to get beautiful crusts quickly (try 900 degrees in the stove in your house!) to the flavours you can get (smoke baby!). So I started dreaming about building a stone oven using local rocks that I would form into some sort of dome.  And I decided I was going to keep this project as cheap as possible, just for fun. 

The initial idea was just to mortar some stones into a simple oven structure that would be heated by throwing a bunch of logs in, followed by the food.  I got the rocks from a crumbling cliff behind the local Provigo (a chain supermarket) - lots of nice rectangular ones. 
So, where to put this beast?  To give it a nice setting, I thought it would be nice down by the river.  I dug into the ground until I hit a solid rocky foundation - probably part of the old river bed.  There won't be any frost heaves here.  I made a base of sand/gravel (from the local old disused quarry, so free of course) surrounded by concrete that the wall would sit on.

The concrete was kept cheap by buying 60 pound sacks of portland cement from the local Home Despot for $9 a bag.  Add 240 pounds of free gravel per batch from the quarry, et voila, lots of cheap concrete.

I used mortar to joint the stones.  Mortar is just a different mix of cement than concrete - concrete uses cement with aggregate of different sizes to form a solid stand-alone "block" such as a foundation, but mortar uses cement, lime and sand to form a bond for bricks and stones used to build walls.  I used "Type S" mortar cement mix (basically portland cement mixed with lime), also $9/60 pound sac that you add sand to.  I sieved sandy gravel from the quarry to get a sand fine enough to use for this mortar, also for free :) As you can see from the pictures, I didn't really know how to mortar properly - my "finger" marks are still all over the mortar!

It was looking pretty good at this stage...wow, at this rate, I figured I could build a stone-walled castle!