Pdx 42" update

[Macrinehart]

mongota - Thanks you for the response. I'm going to try an idea out, and if it fails then I will follow your advice and move backward to move forward.

My idea is to purchase use 3 pieces of Stainless sheet metal to isolate the chimney landing from the chimney itself. My notion is that 2 pieces will be attached to the inner and outer portions of the chimney landing, keeping them isolated from each other while providing a level, smooth base for the chimney. Then I'll place one rectangular piece of SS above without anchoring it, and finally I will anchor the chimney to the upper SS sheet, using the stair-step brick method to build the smoke chamber and taper to the anchor plate.

I do not think I will need any gasket material. The idea is that the plates will provide less friction for movement, while the brick weight of the smoke chamber will provide a stable foundation for the chimney structure. I'll insulate and stucco around the smoke chamber base for added stability and to keep it from slipping out of alignment with the opening.

My two concerns with this approach are that repeated heating and cooling could cause a missalignment between the chimney and the opening in the arches. I think experience will tell, and if it doesn't work then I can deconstruct this part and try something different.

[Macrinehart]

Hello Fellow Oven builders - long time no chat. I have actually been locked out of my account for months, that password recovery email is not working for me. I decided to try again and luckily was able to guess my password with 5 attempts, so Mac is back!

I am also not finished with my oven. Here is where things stand:

1. The dome is finished
2. The opening arches are completed
3. I have wrapped the dome and arches with insulation and covered the entire structure with stucco wire lath.
4. The landscape crew build a beautiful patio around the oven

Items to do:

1. Smoke Chamber construction
2. Curing
3. Stucco
4. Chimney
5. Food prep/service area and permanent cover.

I couple of questions for the pros:

1. Should I do the oven curing after adding the smoke box and before applying stucco?
2. Any special considerations in curing if the build is taking years instead of weeks/months?
3. My smoke chamber is going to be cast. What are the recommended ratios for a cast smoke chamber?

Attaching some recent photos. Show, the new patio, a model of the smoke chamber, and the the cast I am building.

[Giovanni Rossi]

Welcome back! I was wondering what happened to you. Glad it was just a technical glitch.

I'm far from a pro, but your situation is similar to what I did.

So, for #1 and #2:

I ran out of time to finish as winter approached and I didn't want all that water in the refractory when the temps hit single digits. So, I covered the dome with some loose layers of blanket and did a few days of small fires to dry things out a bit before putting it to bed for the winter.

You're clearly past that point now and your dome is well cured.

Once spring rolled around, I fit the blanket on properly and did the standard routine of drying fires before adding the pericrete insulation layers. I had such a wet spring that I redid the drying fire routine once I added the pericrete. Then I brushed on the waterproof render.

I ran into some terminology confusion during my build as "render" is used in many locales to refer to what we call stucco in the U.S. If your stucco layer is non-waterproofing, insulating or not, you're going to want to have that on and then do your slow drying routine. If your stucco is waterproofing, the fellows on the forum would say to dry first then apply.

Looking forward to seeing you cross the finish line.

[Macrinehart]

After reading several posts on castable ovens and the smoke chamber I decided to change directions and use sand to create a mold for the smoke chamber. One of the benefits of changing my mind after starting down a path is I have extra unused materials that find there way into usefulness. In this case a piece of stainless steel that was left over from a prior abandoned effort found usefulness as almost perfectly blocking the underside of the opening for my chimney.

From there I sculped the sand to roughly match the shape of a Styrofoam model I'd built for the just abandoned form. And then the anchor plate I purchased became a guide for sizing and positioning the base of the chimney. Considering comments on shrinkage I used the anchor plate to provide rough opening size and then added about an 1/8" - 1/4" to the radius.

Finally, I mixed up some home brew using a ration of 3:.5:1:1 of sand, clay, lime, and concrete. It was pretty warm today, so throughout the process I was misting my work area keep things damp. Built up the concrete around my mold all in one shot. It seems to have gone pretty well! Everything is covered with damp towels now.

Based on my reading, I will be letting this cure for a couple of days, and then removing the supports under the sand to allow for shrinkage during drying. It's cooling off to the mid-60s for the next few days, should be pretty good weather for slow curing.