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ksmaxey 07-18-2013 02:33 AM

Drying things Out - Water in insullation
I have been firing my new oven for several weeks and have done 2 batches of pizza. When I couldn't get the surface bricks above 350 degrees I began to wonder what was going on. Last night I pulled up one of the fire bricks to discover that the fiber board insullation and sand under the firebrick are wet (over 50% moisture). I am pretty sure now that the water got in during the build during a particularly nasty storm after the brick was in place before the oven was completed and won't be an issue going forward.

So. . . I need the wisdom of this great group?

How do I best go about drying things out?

I can remove much but not all of the brick (some is supporting the dome).

Thanks in advance for all of your help.


Lburou 07-18-2013 09:49 AM

Re: Drying things Out - Water in insullation
Welcome kevin :)

You may find something here that will help you get through the curing process. We all had moisture after building our ovens. Oven performance should get better each time it cycles from warm to hot. The cooling cycles allow moisture to migrate and move on out of the structure. HTH :)

deejayoh 07-18-2013 10:22 AM

Re: Drying things Out - Water in insullation
Is your oven a precast or pompeii? and did you ever have it fully cured?

If the bricks/dome are not holding moisture, I'd say light a good hot fire and keep it going all day. The heat will dry the insulation. But if the dome got wet - I would guess it calls for a full cure. Maybe remove bottom bricks and dry with a heat lamp, then replace them and re-cure the oven.

ksmaxey 07-18-2013 11:16 AM

Re: Drying things Out - Water in insullation
The oven is not precast. It has 2" of ceramic fiber board under the firebricks on the floor the oven. Those bricks are herringbone cut but sitting on a little sand on the ceramic fiber board. The dome is firebrick with 2" of blanket insulation covered with wire and stucco. I know that the blanket insulation is pretty dry.

I did 12 days of curing where I built slightly larger fires each day. I realized I had a problem when I did my first pizza batch and couldn't get the floor as hot as I thought it should be. After batch 2 I pulled up a couple bricks and used a moisture meter that shows the sand and insulation under the floor in excess of 50% moisture. The sand feels wet but has a hard crust so I am guessing that it isn't helping.

deejayoh 07-18-2013 11:22 AM

Re: Drying things Out - Water in insullation
I'm always amazed that there are people who have built entire ovens and THEN post here. I don't think I could have done it w/o the forum. But I digress...

If you think the dome is cured (which it should be after 12 days) then if it was my oven, I would fire it good and long and hot. The only thing that is going to dry the insulation is a combination of heat + time. More heat = less time. Move the fire around from time to time to heat the bricks through across the entire oven. The crust on the sand won't matter.

Lburou 07-18-2013 12:44 PM

Re: Drying things Out - Water in insullation
If you remove some bricks from the floor for drying, I would not build a fire until it has dried out and the bricks are back. A fire when the bricks are replaced would be your best bet. I buy into the strategy that cooling cycles allow the moisture to migrate to areas that will dry with the next heat cycle. YOur oven performance should improve with each firing. :)

ksmaxey 07-20-2013 05:40 AM

Re: Drying things Out - Water in insullation
An Update:

I pulled out the center bricks and found the sand wet. It was wetter than I expected.

I vacummed the sand out with my shop vac and ran a fan into the oven all day yesterday. Last evening, expecting storms, I switched to a milkhouse heater and closed off the entrance. The humidity in the air dropped from 80 % to 15% and when i tested the surface of the insullation it was the first reading with the moisture detector below the max on the meter. Progress.

Today we are expecting more storms so I might keep the heater and add the fan inside to increase the dry air hitting the insullation.

ksmaxey 08-01-2013 04:41 PM

Re: Drying things Out - Water in insullation
Thanks for all the advice.

An Update: After nearly two weeks of alternating a milkhouse heater and a fan the moisture level dropped and leveled out. Yesterday I put in dry sand and replaced the bricks on the floor. I had a fire last evening and the floor temp was significantly higher than before.

Tonight I put pizza dough in after 1.5 hours of pre-heating and got the crust dark brown on the bottom with no problem in minutes. It was cheap flour pizza dough but it proved that all is well. Will try again with 00 dough this weekend . . .can't wait!

Thanks again.

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