uneven hearth

[cecilB]

Re: uneven hearth

It is a JPEG -

We started pulling up the thermal mass of firebrick and it is pretty soft stuff. And the stuff under the brick is still wet - this is after 2 - 3 weeks.
A good learning lesson, eh?
We'll just pour a whole new insulated hearth but I would still like extra thermal mass.
Mine is not JUST for pizzas - I have a pretty good bread business going here, that I won't keep up if I only have my two electric ovens to do all the baking!

And regular fireclay for the laying of the oven floor, but heatstop 50 for the mortaring of the bricks when we start on the dome, right?

Thanks
cecelia

[DrakeRemoray]

Re: uneven hearth

Correct, on Regular fireclay for laying the floor and heatstop50 (the drymix not in the tubs) for building the dome. You can also make a home brew mortar out of the fireclay and (what else is in there?), but the heatstop is easiest to use if you can afford it.

Normally we don't reccomend extra thermal mass, but since you are in the business of baking bread....

Perhaps you could lay the hearth bricks on their side (as opposed to flat). You can also add thermal mass to the dome by coating it with extra heat stop or home brew mortar.

Drake

[cecilB]

Re: uneven hearth

Yes, I was thinking of laying them on their sides, or buying the flatter fire brick...I think it would be better just to lay them on their sides.

I am in the business of baking breads - but not fully committed! How much longer will it take to heat up the oven - I'm not quite sure exactly all the specifics, but I'm guessing it goes like this - you fire the oven up to Really Hot and do the pizza, then by the time you finish the pizzas your oven is ready to take breads...then after that roasts?

Anyway, I will get to that when the time comes - at the rate we're going, I don't imagine this'll be done before winter!

cecelia

[dmun]

Re: uneven hearth

Refractory suppliers sell three inch thick firebrick, for that bit of extra thermal mass without a lot of extra work or expense.

[cecilB]

Re: uneven hearth

ok, we have successfully ripped out all the extra thermal mass of firebrick and most of the insulated hearth - We will build a form around the top, so there will be at least four inches of the vermiculie/portland mix.
And for the extrathermalmass, we will lay the bricks on their sides.

My hands are sore.

Cecelia

[texassourdough]

Re: uneven hearth

I am confident that was not fun but you did it pretty quickly and I am confident you will be MUCH happier in the long run!
Jay

[ThisOldGarageNJ]

Re: uneven hearth

Cecelia,
Lay the bricks on their side like everyone says. I have mine flat and if i cook pizzas on a friday night, I usually heat it up for about an hour an a half, I keep a log burning on the left side.. My point is that if I start cooking about 6 and finish around 8pm the next morning around 8 am my oven is still 300 degrees inside without even putting a door on it. Im thinking if you lay the bricks on their side you will get a pretty good increase in heat retention based on what i know from my oven.

I also recommend a wooden door, Soaked in water before you use it. The water will keep the door from burning and will release steam into the oven which im pretty sure is good for bread baking. The wooden door is what my uncle uses in his oven in Abruzzi. Good luck and be patient and it will all come together. dont rush it, Especially when you get to the curing fires,,, It will all be well worth it.

[cecilB]

Re: uneven hearth

Well, I now am looking at the FB Board and wondering some things - do you put it over the entire hearth surface - over the entire cement slab that supports the actual oven?
Or do you just use enough for exactly under the cooking surface?

We took up all the brick and what remains now is a messy, chunky surface over the slab. I know we could sand it all down or something...but ....ugh!
I was thinking I could pour enough plain old cement to level it all out and then put down the FB boards...?
OR I could just do the portland cement/vermiculite stuff as long as we make it four inches from the highest point of stuff left over from ripping out. Does that make sense?
I would have to buy at least four more packages of the vermiculite - they are in large bales-16#, and they are about $23/package. Plus the portland cement.
The advantage is that I can go get it all today...and I'd have to wait for the FB Board.

Would I only need one layer of FB board? I plan on using my oven for a lot of bread baking, as well as pizza, -
What about the blanket - would I need more than one layer of that over the dome?

I am on a budget - whatever money I make selling my bread at our local (new and very small) Farmer's Market, I get to spend on the oven!

Thanks

Cecelia

[DrakeRemoray]

Re: uneven hearth

You need either 4 inches of the vermiculite concrete OR 2 inches of FB board under the oven floor. The vermiculite concrete is generally cheaper, but more work...

[cynon767]

Re: uneven hearth

Even at $23 a bag, the vermiculite is cheaper. I like the second plan, with the new vermicrete pour. That way you could get the top more or less level and just use the fireclay to smooth it out, like the plans say. It beats either removing all the old vermicrete or pouring a new concrete mini-slab just to put down fb board which you don't even have yet.

You could also look for Perlite; many people here have used it interchangeably with vermiculite, and in some places it's cheaper. I was able to find it at a nursery supply here in northern california for $16.50 for a 4 cu.ft. bag; others have done even better.

[cecilB]

Re: uneven hearth

here's an update on our mess!
We got ALL the "rubble" off the slab - it's nice and smooth. We built the form back up and on Monday we'll do the vermicule mix on that.

As for laying the bricks on the side...the thing is is that I have a lot of used brick - it's what we're using for the dome...and we were going to use fo the whole thing, but we decided to get brand new brick for the floor. SO, I have enough firebrick, and I would like to just use some for extra thermal mass. If I lay the new brick on their sides, I'd have to buy more new brick, probably.

Anyway, It was a setback, but I'd rather fix it now than find out later on that we have to rip everything out.

My other question is this:
Back in the old days, in ancient times, Did they have specific stone for ovens? I mean, we have firebrick, but what did they do?

Cecelia