Hello from PEI, Canada - my 26" Castoven project

[SusQ]

Well, thanks to many hours of reading posts and looking at different builds, I have started my WFO here on the beachfront in PEI. I do have some concerns with our very cold winters, but doing it myself with a thrifty mindset, I am not too worried if it doesn't work out, my budget is $500 Canadian dollars.

So far I built a concrete block base, I just did a dry stack with some post mix in the holes, as because it is so close to the waterfront, someone may make me tear it down someday. I am hoping to bribe my neighbor with pizza to keep him from turning me in! Blocks are super cheap at HD, and I also salvaged some from the waste sort center, you will also see tons of random bricks and building stone in our PEI red sandstone colour, all salvaged from the dump! I did buy new firebrick for the base.

I made my first mistake, I poured aircrete (I have a foam generator and love this stuff because it is super light to work with) under the floor of the oven, then made a concrete countertop on top of it. Then realized that if I put the fire brick right on the countertop, it will radiate the heat out of the oven. Oops. So, I had a stroke of luck, and the retired mason that I bought the firebricks from ($5 cash each) had some scraps of FoamGlas left from a project, and he said he doesn't use it anymore so he gave it to me for FREE! I used the 4" pieces under the firebrick.

[SusQ]

Firebricks over FoamGlas

[SusQ]

Got an idea from a YouTube video on how to cast a dome with sand. I am very lucky to live on the beach here, because it took a lot of sand! I anchored my jig with some salvaged bricks. Quite the learning curve to form the sand, wetter is definitely better! As you can see, our PEI sand is very red!

[SusQ]

We have a lot of wind here on the waterfront, so the strips of newspaper kept blowing off, decided to mix some flour in the water and paper mache it on, worked well! Also made a gallery form out of an old plastic plant pot, anchored it with sand and bricks to hold the shape and weight of the homebrew

[SusQ]

Thanks to DavidS I figured out the homebrew recipe, and my fireclay arrived from Ontario (bought way too much!) I also got some polypropylene fibres from a local concrete company, they only cost me a Tim Hortons coffee and some Tim bits, I love this island, such friendly people! Oh yes, and used a tomato juice can for my chimney, might be a mistake, but its in there now!

[SusQ]

Dug the sand out of the dome today, looks pretty good I think! Its not perfect, but who is! There are some small voids, I was going to leave them, but what do you guys think? Should I fill them??

[SusQ]

Today I was building the stone block wall around the base, as you might have noticed, I made the countertop too small, so I am cheating a bit with the stone to act as a support for the insulation layer. Did I mention that I salvaged all this sand stone block for FREE from a construction site that was throwing it out. It's going to blend in with the beach rocks well I think

[david s]

The voids are really only cosmetic unless they’re pretty big. If you want to fill them use a fine sieve to remove the coarser sand, discard it and mix the rest to a peanut butter consistency, then force it into the voids. A butter knife does a good job for this. Then run over the surface with your finger tips. The voids should be filled while the casting is still a bit damp. As it contains Portland cement you should cover it to retain moisture for a week. This enhances the strength of the casting.
the tomato tin will rust away, but is probably best left in place until it does. You can always build it higher later. The only advantage of a chimney or flue pipe is to keep the smoke out of your face.
Free is always the best price,

Great job.

[Waldenverney]

Great job, thanks for sharing your pictures!

[SusQ]

Insulation time, I used the leftover FoamGlas pieces around the oven, and secured with wire, the voids will be filled with aircrete, just using this a filler and to not waste it.

[SusQ]

Next I had to figure out how to build a form around the oven for the aircrete, which is VERY liquid. I used some old coroplast signs from the airport where I work that were destined for the garbage, some 1/4 mdf and my favorite ratchet straps

[SusQ]

It was very important for this form to hold liquid, so I used some expanding spray foam to seal all the edges, it worked great!

[SusQ]

unfortunately the form was not high enough to fill right to the top of the mesh, which was my goal, but after the first pour set, 2 or 3 days, I removed the form, slide it up 8" and did a second pour on top, I didn't get any pictures of that pour

[SusQ]

We had a bit of a cold snap here in PEI, so I left the forms on for an extra few days before removing, this is what I was left with. You can also see candles burning inside, I did this for 4 days, just to bring up the temperature so the aircrete would set, it dropped down below 4 celsius at night, which is not good for concrete! I am very happy with the rigidity of the aircrete, it set well

[SusQ]

Now the super fun part, my goal is to coat the oven in stamped concrete so that it blends into the rocks along the shoreline. One of the pluses of aircrete, is that you can carve it. I had put the mesh around the oven before the pour so that I had a guide to never carve below that mark leaving at least 4" of insulation, so I just rounded off the edges till I saw the mesh. I built up the edges with waste bricks and started my concrete shell, added pigments to match the natural red rocks on the beach