Applied the top coat over the straw insulation today.
Used a full bag of clay, a quarter package of iron oxide colouring, and a couple heaping spadefuls of sand to start – mixing that all with enough water to get the consistency of thick peanut butter.  I then mixed in about 1/5 of a bale of straw, all cut up pretty fine. Talk about a workout!
After applying the finish coat, I applied a layer of red/black aquarium gravel that I had (and no longer needed) – kind of like a stucco.  Worked pretty good I think – we’ll see how the colour is – right now there are a couple thin spots that have dried, and they look more pink!  I might just mix up a thinner layer with more colouring to apply again 🙂
I’m also thinking that I might have more of the clay applied over the foundation down from the top – kind of like wax dripping down the side of a candle – still deciding though 🙂
 
I’m still working on a design for a steel roof structure to build over the oven – and protect all this hard work from rain and snow!

Well, after getting the main dome of the oven completed a few days ago, I let the oven sit for a couple days, then carved out the door, and pulled out the sand – and it didn’t collapse!
I let the oven sit for another day, and then couldn’t resist building a small fire, to move the process of drying out along.

And no cracks!
Today I started applying the insulation layer – a fairly wet mixture of clay, sand, and straw.  I used fairly equal ratios of sand and clay, mixed with water until I got a consistency that was similar to a medium thick milkshake.  Then I kneaded in handfuls of straw.
Once the straw was completely coated in the clay/sand mixture, I added more straw, and repeated.  I wanted the straw clumps to hold together – so once I thought the clumps were just about not staying together, I quit adding straw, and kneaded a splash more water into the mix.
I then threw big clumps of the mixture around the base of the oven.  I want to try and build up a 4 – 6″ layer of insulation.  Unfortunately, I didn’t have enough clay to make the insulation mixture cover the entire oven.  So I’ll be off to Plainsman Pottery this week to get a couple more bags!  I’ll buy extra so that I can put a final finishing layer over the insulation.

Well, this weekend was a bit of work!
Saturday I formed the sand dome, which acts as a form for the actual oven.  Used about 500 lbs. of sand!  The floor of the oven is an elliptical shape – 32″ wide x 36″ deep.  The height is 17″.  After shaping the dome, I covered it up with junk mail flyers – soaked in water.

The following day, I built up the oven itself, making a lot of baseball sized balls of sand, clay and water.  The mixture wasn’t too wet – just enough to keep the sand and clay together.

I did manage to get the form covered over completely – with a brief interruption by mother nature and some much needed rainfall.  In a couple days, I’ll lay out the oven door, and cut it out.  Then the moment of truth when I get to remove the sand form!  I’m planning on making the opening around 11 1/2″ tall, and 16 – 18″ wide.  Once the opening is made, I’ll build a door, and then add 3-4″ of straw and clay insulation to the exterior of the oven.

The other evening some friends and I gave up an evening of cards, foosball, and whisky drinking to instead demolish a stone and concrete planter in our front yard, and using the rubble from it, and a large brick planter in our back yard, built up the base for my pizza oven.  We still had some whisky, and enjoyed a great evening around the fire pit as well 🙂
Only bad part was me getting stung in the eye by a wasp that I upset when digging out the gravel from the demolished planter in the back yard. That was a couple days ago, and the swelling has come down – so I don’t look like Igor anymore!
 I didn’t use any cement/mortar for now – everything is just laid in place and we’ll see how it works out!  I ended up pouring all the bags of play sand onto the base and just lightly tamped it down.  I might be able to add more sand once I tamp it down a little harder, and level it out.  Next step will be to lay out the insulation bricks, and then the kiln bricks that will make up the actual floor of the oven.