gt40's Pompeii Oven 42" build log

[ggoose]

Re: gt40's Pompeii Oven 42" build log

Your build is looking good gt40. The chain is a unique addition. Did you sink the bolts that supports the brackets all the way down into the hearth, or just into the vermicrete? Too bad you have to cover it with insulation; the chain would be a great conversation piece .

gene

[gt40]

Re: gt40's Pompeii Oven 42" build log

Update:

Well, I got some time to work on the oven and it finally is starting to take shape. Here are a few pics:

top shot:


Inside shot:


I really need to clean things up at this point. I don't know how all the other ovens are so clean. I guess I will just go in and scrub followed by going in with a and mask and face shield and just grind it all clean. Part of me hopes when I finally get it done and up to full temp it will burn some of this stuff off. One can hope...

Final shot with the chain harness:



I will see if I can finish the dome tomorrow. Building these things is hard work!

Thanks for looking.

[gt40]

Re: gt40's Pompeii Oven 42" build log

FWIW, During my oven's last curing fire -after two hours of a big fire and without insulation- the top of the outside of the dome approached 300 F while the inside of the dome was 950 F.

Thanks for the observation and also for posting that newbies guide to forno bravo. It was invaluable to me as I go and try to learn how to build this thing.

I have a question and a comment. First the comment.

I'll be demolishing my 30" low dome oven soon as I am building a 42" low dome to replace it as we speak. My old oven was "buttressed" with stainless cable so I will be able to chime in how it held up shortly. The oven was run at 1000F for hours at a time many many times, so should be a good indicator.

Now my question. What interior height did you decided on for the 48" oven? I just ask because as the dome is going in now it looks like it is gonna be pretty high. My 42" oven is going to have a 12.75" dome. For a 48" oven I think the rule of thumb put's it around 14".

Mine is going to be around 17"/43cm with the floor at 49"/124.5cm diameter.

Interesting you used stainless cable. I was going to use that first but ended up with the chain because it was so much cheaper than the 321 stainless cable I wanted to use. The stainless is much more resistant to the heat and holds strength at higher heat levels.

I spoke to my friend who is a mechanical engineer and the expected loads on the chain even at high pizza temps are not even close to the chains strength, even degraded by heat.

Anyway, Good luck with your next build, post some pics...

[shuboyje]

Re: gt40's Pompeii Oven 42" build log

I have a question and a comment. First the comment.

I'll be demolishing my 30" low dome oven soon as I am building a 42" low dome to replace it as we speak. My old oven was "buttressed" with stainless cable so I will be able to chime in how it held up shortly. The oven was run at 1000F for hours at a time many many times, so should be a good indicator.

Now my question. What interior height did you decided on for the 48" oven? I just ask because as the dome is going in now it looks like it is gonna be pretty high. My 42" oven is going to have a 12.75" dome. For a 48" oven I think the rule of thumb put's it around 14".

[Lburou]

Re: gt40's Pompeii Oven 42" build log

FWIW, During my oven's last curing fire -after two hours of a big fire and without insulation- the top of the outside of the dome approached 300 F while the inside of the dome was 950 F.

Yeah I think you are right. But would an oven temp. on the outside of the bricks be enough to anneal the steel? I think you have to go pretty high to do that. This is a good question maybe only experience will be the answer.

[gt40]

Re: gt40's Pompeii Oven 42" build log

But once steel expands and the temper is lost I thought it stays expanded?

I chose basic steel chain i.e. ? Low carbon chain

This is low carbon steel and not hardenable so it doesn't "temper" or harden.

It does however weaken while hot. The chain I chose has a working strength of over 1000 lbs/450 kg and breaking strength of over 3000 lbs/1350 kg. Even allowing for reduction of strength at pizza oven temps, it should be plenty strong. That is why I chose chain over steel cable.

[david s]

Re: gt40's Pompeii Oven 42" build log

Then it should be ok. You won't get the outside of the bricks at the base to anything like that temp.

[brickie in oz]

Re: gt40's Pompeii Oven 42" build log

Any prolonged soaking of heat above 600c will do it.

[david s]

Re: gt40's Pompeii Oven 42" build log

Yeah I think you are right. But would an oven temp. on the outside of the bricks be enough to anneal the steel? I think you have to go pretty high to do that. This is a good question maybe only experience will be the answer.

[brickie in oz]

Re: gt40's Pompeii Oven 42" build log

But once steel expands and the temper is lost I thought it stays expanded?

[david s]

Re: gt40's Pompeii Oven 42" build log

I think the expansion of the chain should be about the same as the expansion of the bricks. It is the same for steel in reinforced concrete anyway. For kilns the steel bracing is usually on the outside and they are cooler than the inner kiln bricks, which means they hold the bricks in really tight. With your chain being in the insulated area it should be nearer the same temp as the bricks so I would expect it to work well.

[brickie in oz]

Re: gt40's Pompeii Oven 42" build log

Wont the chain go slack once its been soaking in heat for a couple of hours?

[chidding]

Re: gt40's Pompeii Oven 42" build log

That is awesome! really impressive setup!..

Pretty sure that will be meteorite proof!

[gt40]

Re: gt40's Pompeii Oven 42" build log

Update:

After reading the posts about bracing low dome ovens and living in earthquake country in southern california, I finished my oven bracing system. I also got my transition under control although I will need to grind a few bricks in the center to keep the lines going properly.

Here are some pics:



welded chain support anchored into the foundation:



back shot of the chains


Transition:

[gt40]

Re: gt40's Pompeii Oven 42" build log

gt40, your build looks brilliant. You should be proud of your progress to date, I'll be keeping a close eye on how you tie your arch into your dome (I'm not quite there yet, but that seems to be the tricky part of this whole project).

That's a different take on the indispensable tool, do you have to adjust it for each new row? I have been thinking it would be handy to have an indispensable tool to build a neapolitan style dome.

Thanks for the comments. I am learning as I go and all the awesome threads and comments on the site have helped me learn and avoid problems.

In answer to your question, yes, you have to adjust each time the angle changes on the low dome.

Basically I made a profile form of the dome shape with foam board to use as a basis for setting the angle on each course of bricks. When starting a new course, I found I could clamp the brick to the indespensible tool, adjust the height and offset till the brick matches the dome profile on the foam board and then I just tighten the c clamps to lock the angle on the tool and start laying the course. The tool is just a hinge with a piece angle iron on each end and some scraps of square tube so you can clamp the square tube in the angle to set height or offset.

As far as the transition, I am going to see if my calcs will work out on the angles. Hopefully I make a support course where the arch is and then I will be able to continue the course above it as a perfect circle.