dmun's 36" geodesic oven Pompeii Oven Construction Discuss dmun's 36" geodesic oven in the Pizza Oven Design and Installation forums; and a broken blister from the five minutes I forgot to wear gloves. Yikes. I plan to support the row ...

[dmun]

and a broken blister from the five minutes I forgot to wear gloves. Yikes.

I plan to support the row of blocks with a re-inforced concrete header for supporting the masonry chimney. The new lintel should take all the weight, and keep the existing bricks intact.

Plan B on the window opening is to fill it with glass block. The wavy texture will complement the "rustic" blocks, and let some more light into the workshop.
Did you know that glass blocks are ten bucks apiece? Off to eBay.

[redbricknick]

Kind sir. I covet the consistency of your refractory mortar. Pray tell, how did you make such fine mud?

[dmun]

Heat Stop 50 is a dry pre-mixed refractory mortar. It's a brand name, and I suspect that the stuff that James sells is a similar product. I've only ever used Heat Stop, and the reason is that it's just great. It mixes easily with just a bit of water to a peanut butter consistancy, spreads like a dream, and sticks firebricks together strongly, and with a water resistant bond.

Here's the link.

I get mine from Progressive Brick in northern NJ, who also sells red firebrick and the superior clay rumford throats. It's fifty bucks for fifty pounds, and this expense is part of why I used the cut-every-brick geodesic plan.

The good news is that with all of my oven pre-assembly, and putting together the rumford firebox and throat, I've used only about half of one bag. The secret is to keep your joints tight - 1/16 to 1/8 inch is plenty for a strong bond.

[dmun]

Tonight since I'm getting close to putting up the dome, I did as much dry assembly as I dared without a very good armature.



The first two rows pretty much support themselves. I used a stick to hold up the first hexagon, thinking that the others would lean against that. Uh, no. I managed to get three hexagons up without endangering the structure too much.



Here's a top view:



and another one.

This side view shows that the pieces don't fit together like legos. The pieces are slightly out of flat, which effects their fit.



What did I learn?

I need a better armature, to support the center of each piece. The slight variance in the flatness of the bottom which showed up as 5/16 of an inch at the center of each half hexagon in the drawing is in reality almost half an inch.

If I use a full height (4") soldier course as drawn, I'll end up with a 20 inch high dome, and indeed that's what I drew. I now know that it shouldn't be any higher than half the dome diameter, so I'll have to cut those bricks in half. Just as well, as it looks like I'll have to zig zag the support layer to get things to fit together.

It looks like the outside diameter of the oven fits, which I was worried about, since the rumford throat ended up a little bigger and a little further toward the oven than planned.

[Les]

Dude – your soccer ball approach is very, very, impressive. Keep the pictures coming, can’t wait to see the vent. GREAT work!!

Les…

[maver]

Yeah, that variance looks like a problem

The size of those pieces looks like they will need good support until cured. You don't have the advantage of building self supporting courses, but it will have tight seams. I'm guessing you have a support structure in the works. I like it.

[dmun]

It poured rain the day I was going to work this weekend, but I managed to dry fit my floor:







It's not as flat and smooth as a billiard table, but I think it's more than good enough for this application.

When you get your bricks, pick out the crisp clean ones for the floor. You don't want the bunged and chipped ones here. That wouldn't be a problem for most people who build their floor before their dome.

[james]

David,

We are all so impressed. This is just wonderful. I can't wait to see how she does under "fire".

One thought on our billiardball comment. I did get one brick too high relative to the rest of the cooking floor, where it would bounce the pizza peel. Many firings later, I have knocked the edge off that brick with my peel (and probably should have crawled into the oven and hit it with a sander), but as a general comment, that might be a good rule. Take a pizza peel and push it across the floor and see if anything catches.

James

[redbricknick]

DMUN, you are a true innovator. Tha fact that your oven is being documented so generously makes me truly happy that I live in this technologicaly awakened era.

[dmun]

Here are the half bricks cut for the soldier course:



From my preliminary assembly, I thought that I needed more than the 5/16 ramp up in the center of the half-hexagons, so I cut them with a steeper angle. That didn't work at all, and I had to trim them to the drawn angle.



Here's the preliminary layout with the first course laid down next to it.

Here's the dome set up with the six-point armature I built to support each polygon at its center: