Author Topic: wood burning oven improper curing earthstone model 90  (Read 3581 times)

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Offline kypizza

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wood burning oven improper curing earthstone model 90
« on: January 05, 2013, 12:21:33 PM »
It is a sad day in Kentucky....after what I thought was enough curing....two small fires 1-2 hours each two days in a row. I felt it was time to increase the fire strength.
bits of concrete from the roof of my brand new oven started to pop off.  I was stupid enough to then get on the phone with the disney vacation club to schedule a vaca for the family only to be
interrupted by a loud explosion and a large amount of smoke.

front of my pizza oven now has little hairline cracks on both fronts that course across the cultured stone.
 the dome of my oven looks horrible....

so stupid....feel like a failure at becoming a pizzaolo even before trying....  :'(

any words of advice, shared sorrowful experiences, I told you so's , even ridicule is welcome..... :'(


Offline ThatsAmore

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Re: wood burning oven improper curing earthstone model 90
« Reply #1 on: January 05, 2013, 12:30:15 PM »
Sorry to hear/see your misfortune.  

I'm sure others will ask, did you build it yourself?  What materials were used? The more info you can provide, the better advice you will get from the many here that have 1st hand building knowledge.

Again, sorry about your woes.
Who put that pie in my eye ?

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #2 on: January 05, 2013, 12:56:43 PM »
build by mason to manufacturers specs. perlite concrete mixture above the dome of the concrete modules. cinderblock frame with cultured stone exterior

I guess I was just too stupid and didn't cure it long enough to get rid of all moisture in the big mass of concrete....

it must have heated up too fast and the steam/moisture expanded too rapidly and BOOM....I guess....

The manufacturer states in one sentence in their manual on line ( I see it now AFTER all of this) that improper curing will result in small pieces of concrete dome popping off. they say it won't hurt but just points to the fact that you need proper curing.

I'm waiting to hear back from Maurice of Earthstone ovens....i guess they aren't in on saturdays. This kinda wasn't small pieces.....I should have pulled the wood out when I saw some small pieces popping.....The manual also says no more than 4 pieces of wood in oven at any given time..
This manual is the one I found after the fact on line googling...."dome pieces popping off", not in the literature sent by the company with the kit......

Either way...I guess all my fault .....I just hope it can get up to temp and hold temp  now after all this....

any earthstone oven owners feedback welcome....

Offline TXCraig1

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Re: wood burning oven improper curing earthstone model 90
« Reply #3 on: January 05, 2013, 02:41:14 PM »
My guess (assuming that there is not a bunch more concrete about to fall out) is that it won't affect the functionality much, if any. My oven has cracks from thermal expansion all over it - some a LOT bigger than those in your pictures. I don't have pieces of brick falling from the dome though... I hope it turns out OK for you.

CL
Pizza is not bread.

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #4 on: January 05, 2013, 03:02:35 PM »
Thanks CL,

The largest chunk that fell out was the one in the pic. but lots of smaller ones are in the ashes. I feel like an idiot after reading some of the more
contientious owners on the fortunabravo forum.   one series of posts make curing quite a detailed ordeal but I guess it sure beats the explosion I had.
I believe the anecdote where a chunk of the dome blows out of the opening....

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #5 on: January 05, 2013, 03:06:43 PM »
earthstones website states that dome pieces are 4 inches thick. So I have that and at least 4 inches of perlite concrete above it.  My dome is probably 3 inches now...

Offline Tscarborough

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Re: wood burning oven improper curing earthstone model 90
« Reply #6 on: January 05, 2013, 03:13:51 PM »
There are several incongruities in your posts.  To be clear, the enclosure is CMU coated with adhered veneer?  If so, there should be no direct path of expansion from the oven to the enclosure, and thus nothing the oven does will cause the enclosure to crack.

Secondly, you do not mention insulation under the oven, is there perl-crete there?

Curing is very important, and as manufactured ovens get more popular it is even more important.  Ideally, an oven will sit in a warehouse for a month or three before being shipped to a customer to allow it fully (chemically) cure and attain a moisture content commiserate with the ambient humidity.  A green oven of cast refractory should not really be fired for at least a month after production, and then should be dried with tiny fires before firing.

The important part of a curing fire is to start the fire small in order to heat the entire mass equally and slowly, then step it up gradually to avoid thermal shock (those chips and pieces like you have).  That is to say, when the oven is green, not only is the amount of moisture a problem but the material itself will not have achieved the strength needed to withstand the rapid expansion from heating.
All that said, you will be OK, so long as it is insulated under the oven, and you ease off, if not refrain, from any more fires until the oven has fully cured.  The spalls and cracks are mainly aesthetic issues at any rate.

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #7 on: January 05, 2013, 04:35:32 PM »
Thanks T. Maurice of Earthstone called me to reassure of such but he did point out one flaw in my mason's build which is that there is not venting of the insulated perlite/concrete above the dome.
The underside is not insulated. It goes 1/2" concrete board, 4 " slab and then 1" sand/concrete mix then hearth tile.  For indoor installation, the manufacturer recommended fiberglass insulation with the sand/concrete mix but said
you don't need it for outside installations so the mason didn't.

The mason is coming back monday to drill holes in the mortar in the brick above the dome plus 4" perlite/concrete so it can cure properly.

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #8 on: January 05, 2013, 04:37:34 PM »
any tips on how to insulate the bottom after the fact? is the sand/concrete layer considered insulation under the hearth tile?

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #9 on: January 05, 2013, 04:39:19 PM »
one granddaddy of a spall!


Offline Tscarborough

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Re: wood burning oven improper curing earthstone model 90
« Reply #10 on: January 05, 2013, 04:56:08 PM »
In an enclosed oven, the perlite should be used alone and dry.  Just pour it in.  If you have perlcrete in between the oven and the exterior, it will cause the exterior to crack when it heats up, as well as not provide as good (but still far above adequate) insulation.  I am not telling you this so you will alter yours, just as an FYI on best practice.

Is your floor under the dome or inside the dome?

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #11 on: January 05, 2013, 05:24:36 PM »
under

Offline Tscarborough

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Re: wood burning oven improper curing earthstone model 90
« Reply #12 on: January 05, 2013, 05:58:33 PM »
Well, you will just need to buy a little more wood.  Cure it out and cook pizza.

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #13 on: January 05, 2013, 06:19:32 PM »
Amen Brother! don't sweat the small stuff right? 

Offline Bill/SFNM

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Re: wood burning oven improper curing earthstone model 90
« Reply #14 on: January 05, 2013, 06:29:41 PM »
any tips on how to insulate the bottom after the fact? is the sand/concrete layer considered insulation under the hearth tile?

Here's a mod I made - not exactly insulation, but it increased the thermal mass of the deck. I purchased some extra floor bricks from Earthstone and placed them on top of the existing deck. I trimmed the new bricks so that they cover about 60-70% of the deck. The coals get pushed into the lower portion. My goal wasn't to increase the thermal mass, but to bake the pizza a few inches closer to the dome and a little further from the fire for a better heat balance . Still tweaking this, but pretty happy with it. Main drawback is the it makes it more difficult to sweep out the ashes, but I use a fireplace vacuum cleaner to solve that problem.

I could take a photo of the inside if you are interested.

You may want to get a lot of practice firing and baking with your new oven and enjoying its fruits before considering this.

Good luck.

Offline kypizza

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Re: wood burning oven improper curing earthstone model 90
« Reply #15 on: January 05, 2013, 08:08:53 PM »
I would love pics Bill. I think I will post a pic tomorrow of the dome of the roof of the 90. too smoky still. kinda show the world what NOT to do. ;D

Offline JConk007

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Re: wood burning oven improper curing earthstone model 90
« Reply #16 on: January 05, 2013, 09:32:32 PM »
OH no sorry to hear that about your beautiful new oven !
My earthstone is constructed exactly as you did -conc board , 4" slab, 1"  lean cement ( hardest part of build)  Then the bakers tiles. Perlite over dome mixed with just a touch of mortar mix to hold form kinda glue it together but still open. Di have vents both sides of roof.  Nothing Has not moved in 7 years still near perfect ! I did do about 8 small fires before I went to 500  and 3-4 @ 500 before I went to 900 !  not a chip out of place just not a nip here and there but expected with use
they make I high temp patch material that you can fill and will hold but you gotta get in there some how ?
John
I Love to Flirt with Fire! www.flirtingwithfirepizza.com

Offline Tscarborough

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Re: wood burning oven improper curing earthstone model 90
« Reply #17 on: January 05, 2013, 10:04:54 PM »
You also have to get it clean enough to patch which means burning off the soot, so while it can be patched, you should finish out the curing cycle first.

Offline breadstoneovens

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Re: wood burning oven improper curing earthstone model 90
« Reply #18 on: January 05, 2013, 10:33:16 PM »
Terribly sorry to hear about all that.

Curing, as it was said earlier, is extrimly important. I recommend 3 days of small fired prior to progressively bringing the oven to full temp on the 4th day, regardless of the brand.
Also venting as you mentioned above is very important, so moisture can escape.
Just so other forum member know for a reference, an oven should be cured with just the ceramic fiber blanket on it. If you do a vermiculite or perlite dome, then the moisture can't escape properly. If already built that way, you should then take 7 to 10 days with small fire to cure your oven.

For the floor, I think it may not be a bad idea to place some insulation under the slab supporting the oven. That will help preventing too much heat loss. Ceramic fiber boards could easily be screwed to the slab.

For the piece that came off I have some refractory concrete glue that I would be happy to send you. Just sent me a PM with your address if you want it, no charge ;)

Good luck,

Antoine
WFO cooking is about passion.

Offline Bill/SFNM

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Re: wood burning oven improper curing earthstone model 90
« Reply #19 on: January 06, 2013, 03:50:49 PM »
I would love pics Bill.

Here is a photo of the inside of my Earthstone Model 90 where I hope you can see the baking platform I added as a temporary mod. You can also see what the inside of a Model 90 looks like after about of 11 years of relatively heavy residential use in some pretty extreme weather conditions (e.g., firing up from a cold start from 5F to 900F+). 


 

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