Smuth's 36" Pompeii Oven

[mfiore]

Re: Smuth's 36" Pompeii Oven

Scott,

Looks like you're off to a great start. The amount of Heat Stop you use depends a great deal on how much of an effort you want to cut your brick. If you cut angles and bevels on each course, your bricks will fit tight, with little mortar. If you just use 1/2 sized bricks all the way up, you will need more mortar to fill the gap. Both methods seem to work well, just a matter of preference. I chose to cut the bricks (for the most part) with small mortar joints only because the Heat stop was so expensive relative to the firebrick.

[dmun]

Re: Smuth's 36" Pompeii Oven

dmun, did you not add water to your fire clay mixture? is there an advantage to leaving the water out?

Yes, you can play with the level until you get it just right, and then dampen the floor to set the mixture. This method was the brainchild of Alf, FB's UK rep.

As for me, i just plunked my bricks down on insulation board. No muss, no fuss.

Also, I am going to pickup the Heat Stop II I need. How many bags do you think I will need for the 36" oven? I was hoping to get away with 2. Especially at $65 a bag.

I used one bag, but i cut every brick, and i don't recommend that unless you're stark raving mad like me. I think folks have used 3 to 4 for the entire mortaring of the dome. If cost were an issue, i suppose you could use heatstop for the inner joints exposed to the heat, and then infill the big voids with the cheap homebrew mortar.

[smuth10]

Re: Smuth's 36" Pompeii Oven

Thanks Dino. So far it has pretty much been labor only. I am a little worried about the dome and cutting all of the bricks. I am still not sure if am I going to cut angles on all of the bricks or just use extra mortar.

Mike, I agree with you, at $70 a bag it is pretty crazy. I think I will need three bags. I am leaning towards cutting angles on the sides and just using shims on the bottoms. I guess it is really a matter of how comfortable I get with the tile saw.

Dmun, I think I may do the same with the fire clay. I wish I had your patience, but I think I may just buy extra HS and return what I don't use.

Thanks again for everyone's input.

[smuth10]

Re: Smuth's 36" Pompeii Oven

So I had time to pour the insulating layer last night. It's funny, even after reading everyone's posts about how weird it is to work with the percrete mixture, I still am not sure I did it right.

The first mix was 15 gallons Perlite and 3 gallons portland cement and it was a little too much for my wheelbarrow to hold. I put all of the dry ingredients in my mixer for a couple of minutes and then added it to the wheelbarrow. I added the water and used a garden hoe to mix it up. It came out pretty good I guess. I ended up using about 6 CF of perlite and just over a half bag of portland cement(94lb bag). The area is 45" x 50" x 3 3\4" deep just to give you an idea of materials used. Last night before I covered it, it seemed like there was no way it was going to be solid, but when I checked it this morning it was starting to harden up. The top pieces are still pretty loose. Is this normal?

So the questions I have....

How long should I leave this covered?

Also, I want to pour the rest of the cement around the edges this weekend. Do you think three days is enough time for me to be able to take the inside forms off? After I pour the concrete around the edges I am planning on letting the whole thing sit until next weekend.

Thanks again and sorry for the long post. I am starting to stay up at night thinking about this thing. I may need start a POAA group. (Pizza Oven Addicts Anonymous)

[smuth10]

Re: Smuth's 36" Pompeii Oven

Forgot to add the pics

[Frances]

Re: Smuth's 36" Pompeii Oven

I may need start a POAA group. (Pizza Oven Addicts Anonymous)

I think we've already go one of those... its called the Forno Bravo Forum.

I'm not too hot on building adivce, but it sounds as if your timplan should work, as long as you're carefull and can resist poking the exposed edges of insulation to see if you can take it apart - you probably can but shouldn't.

One piece of advice I can give you though is this: don't worry too much about laying awake nights worrying about your oven. Its all a necessary part of the construction process. So in fact you're right on track there. I can remember I'd get up in the middle of the night sometimes to look out the window and check my dome hadn't fallen down...

[pizza_bob]

Re: Smuth's 36" Pompeii Oven

Hello Scott,

Great job on the oven!
I am building the 42" Pompeii style oven. I am not far behind you and would like to keep in touch. I have the forms up, rebar in place and ready to pour the 3.5" concrete structural layer. I have been beating myself up trying to figure out what to do for insulation layer! One day it's vermiculite, the next day it's perilite, then foamglass, then FB board, then Skamol, then Ytong...
The oven will be mostly for pizza and I am building this with a 15" interior dome height. Here are pictures of progress. I will be pouring the concrete layer Monday.

Take Care,
Bob

[smuth10]

Re: Smuth's 36" Pompeii Oven

Thanks Frances. So far it has not been too bad, but I am worried about the construction of the dome. I have a lot of questions about how I am going to do certain things, but I am hoping it will come together when I get to that point. Jim is being kind enough to make me one of his special brick jigs, so that should make things much easier for me. I am shooting to have most of it done and operational for a July 4th party at my place. Weather permitting it should not be a problem.

Bob, your foundation looks good. I am assuming you decided to pour the walls instead of using cider block because of the fact you are building it into the side of a hill?

I was able to get the get the rest of the hearth poured this weekend, but I made a pretty big mistake. I put the screws in the wrong place for the inside forms and could not get it unscrewed to take it out. DOH! I had to tap on the sides and slowly lift it out. I cracked one corner but I am hoping the addition of the concrete around the edges will lock everything in. Other than that it seems pretty solid.

BTW, I went to pickup my HF tile saw and it was on sale for $229. They also let me use the 20% off coupon I had. It ended up costing me $184. Pretty sweet deal.

[smuth10]

Re: Smuth's 36" Pompeii Oven

I had time to remove the hearth forms tonight. It looks pretty good but I thought I had gotten all the air pockets out, but I guess not. That and some of the percrete is a little loose on the top. Is this pretty normal stuff

[Frances]

Re: Smuth's 36" Pompeii Oven

Is this pretty normal stuff

That probably depends on who you ask... but it does look a lot like mine did.

Seriously, you'll be fine. That upper layer of concreate doesn't have to support anything anyway, so a couple of airpockets won't hurt, and the perlcrete is just like that.

[smuth10]

Re: Smuth's 36" Pompeii Oven

Thanks Frances. I may just take some mortar and clean up the sides a little.

I have a question for those of you that have used the Simpson DuraTech vent system. If you go straight up through the ridge, what did you use as a storm collar? Or did you just buy the elbow set and offset the chimney so you did not have to go through the ridge? That way I guess you could use one of the regular storm collars they make. I would rather not spend the extra money on the elbows as they are $$$.

[bbell]

Re: Smuth's 36" Pompeii Oven

Looking great Scott.

I had my chimney go right up through the ridge of the roof. This makes it very difficult (for me) to insure it's flashed correctly and watertight. Cutting the metal roofing to match the pipe was not all that tight. I ended up building a box that straddles the roof ridge and gives a flat spot to connect the top flashing. Very painful....

If I was to do it over I think I would have the roof just angle down from the front to the back at an angle that works with off the shelf flashing. A good example would be the build by jrparks (http://www.fornobravo.com/forum/f8/n...e-wa-6256.html).

Also, it seems that 8" pipe is getting to be harder to come by and often special order. 6" pipe and parts are more often in stock. At least in this neck of the woods.

Hope this helps,

[smuth10]

Re: Smuth's 36" Pompeii Oven

Thanks Bill.

So, you are saying a flat roof with a slight pitch towards the back would make it easier to install a flashing around the vent pipe. I had never thought of doing that. I am not sure I like the way it looks, but it would make it a lot easier to make the transition. They want a crazy amount of $ for the SS elbow set from Simpson, but I would be able to use a standard flashing kit.

Would the elbows cut down on how well the chimney draws?
Would there be a problem with using Galvanized?

[bbell]

Re: Smuth's 36" Pompeii Oven

Scott, it seems like I've seen more flashing available for the pitch rather than the peak. Looking through the pictures though there does seem to be few that have the flue on the pitch.

I'm sure there's some knowledgeble readers who can map out the best strategy when going through the peak. I shouls have asked when building mine....

Here's some pictures of ovens that have both peak and slanted roofs.

[wlively]

Re: Smuth's 36" Pompeii Oven

Scott

I couldn't find any affordable premade options for my Duratech so I made one. My pipe goes straight up thru the roof peak. I cut a whole 6" wider than the pipe. I screwed flat metal flashing pieces to cover the gap. Then made a box out of left over Durock that would sit on the roof, two sides notched to sit on the peak. I then crown filled the box to seal around the pipe with stucco base and stucco'd outside of the roof box to make it look like a square chimney. Of course my enclosure is stucco, so you may have to modify the plan to work with your finish of choice.

I didn't take any pictures of the process, but you can see the idea from these;