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  #11  
Old 05-19-2010, 06:17 PM
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Default Re: How hot should underside of hearth be getting?

It also is a function of "oven size" which ultimately boils down to mass inertia. The bigger the oven the longer it's going to take to get up to temp and even longer to maintain it. My 60" takes at least 2 hours to get up to temp and hold that temp. I suspect the 45 min are smaller ovens with less mass inertia to push the heat into and can maintain it with a little more heat soak.

That said, a large oven should maintain the heat longer. Well maybe, it depends on many things like amount of insulation, etc, etc. Each oven is different, so just because yours isn't heating up in 45 min doesn't mean there is something wrong. If you used the FB plans and did it the way they describe it here, you should be golden. Cheers John
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Old 05-20-2010, 02:57 AM
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Default Re: How hot should underside of hearth be getting?

You might get the oven to clear in 45 mins but it takes longer for the heat to soak through to the full thickness of the brick floor. That is why the heat drops off fast because it is wicking its way to the outsides. My oven is small but I still use 1.5 Hrs for pizza cooking unles I'm only cooking 3-4 pizzas.
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  #13  
Old 05-20-2010, 04:25 AM
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Default Re: How hot should underside of hearth be getting?

Have any of you guys ever checked the temp of the underside of the hearth?
Mine seems to be a bit hot. I will be doing a couple of pizzas tonite so will check the temp but I think it is hotter than it should be.
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  #14  
Old 05-20-2010, 05:25 AM
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Default Re: How hot should underside of hearth be getting?

I need to also check mine as well, will let you know.
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Old 05-20-2010, 12:43 PM
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Default Re: How hot should underside of hearth be getting?

The underside of your hearth should never be any more than cosy warm. If it is then your insulation is either inadequate or your oven still has moisture. The moisture on the bottom always seems the hardest to eliminate.
Dave
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  #16  
Old 08-30-2010, 08:22 AM
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Default Re: How hot should underside of hearth be getting?

I am hoping that moisture is the case in mine...I have 4 inches of 6/1 ratio insulating cement under my floor, heat for 1 1/2 hrs to temp and the floor begins to noticibly cool after about 5 pizzas. I maintain heat while cooking as well. I did check after the last firing and the underside of the slab was hot, didn't temp it... mostly in the rear wood storage just below the main body of the floor. I read an earlier thread where it was suggested that the underside get insulated to help retain floor heat better I may try this. Any thoughts...could it be as simple as just some moisture??

Peter
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Old 08-30-2010, 09:55 AM
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Default Re: How hot should underside of hearth be getting?

I suppose I should mention that it was only my 2nd full fire after successive curing fires

Thanks again,

Peter
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Old 08-30-2010, 10:07 AM
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Default Re: How hot should underside of hearth be getting?

It will take a long time to drive all the water out of your insulating concrete. Vermiculite and Perlite are sold as soil additives specifically because they absorb water. As you use your oven it will get better and better.

I think your heat under the slab is an indicator of damp insulation.
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Old 08-30-2010, 10:54 AM
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Default Re: How hot should underside of hearth be getting?

Thanks Dmun,

I was hoping that was the case...I'll continue to monitor it and update as changes; or no changes; take place.

Peter
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Old 08-30-2010, 01:37 PM
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Default Re: How hot should underside of hearth be getting?

After the curing fires it seems to take about 10 cooking firings to totally eliminate the moisture. That is good because it gives you another reason to fire the oven.
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