Oven Curing

[Troy]

Re: Oven Curing

I am at day 7 had a fire last night and I see a few cracks and a fair amount of smoke coming out. I can see the fire in the oven in some of the cracks. What would be my next step to fix the cracks. (heat stop or high heat caulk from the wood stove store)

[Jim Bob]

Re: Oven Curing

James,
I read thru the info in this thread but did not see this question addressed. Is there any problem with mixing some lump charcoal with your kindling in the curing process?
I have fired my oven twice, the first with newspaper(about 20 minutes to reach 200 degrees) and the second with newspaper & kindling(5-7 pieces) and could only get the temperature up to 228 degrees! Since the firing schedule only called for a couple of pieces of wood on the second firing, I was hesitant to load it up to reach the 300 degree mark. I use lump charcoal often in Green Egg and it is a clean burning and hot burning charcoal which would help establish a hot bed of coals earlier. But i see no reference to it in the forum postings.
Also cardboard burns much hotter and longer than paper, & I wondered if I might start the kindling faster with it. I do have one of those propane torches that I will use too.
I guess I am concerned that I will even be able to reach that 800 degree mark in 7 days without a whopping fire.
I also assume that it is important to locate and keep main fire in the center of the cooking surface for maximum effect.
Would appreciate your help.
My oven is complete and looks very, very good. I will be sending my pics over soon.
Jim Bob

[CajunKnight]

Re: Oven Curing

Keep working with the small fires and just get bigger over time, as the oven dries the smaller fire will produce more heat. Moisture acts like a thermostat. This is why smokers with water pan work so well and easily maintain a heat of around 215 to 225 degrees. Take out the water and the heat jumps up(possibly double) with same fire.

[Jim Bob]

Re: Oven Curing

cajunknight,
Thanks that helps. Do you know the answer concerning lump charcoal in the WFO? Is there a problem with it at all?
Jim Bob

[Wiley]

Re: Oven Curing

I used charcoal briquets for my "dryout" and since my oven has a steel liner there is no evaporation thru the inside. I found that in spite of slowly raising the temp over several days I was having very little actual drying of the basalt concrete cladding. This was measured by means of a moisture meter like one uses for wood. It was not until yesterday where I built a fire and slowly over the course of several hours heated the dome thruout. No one has mentioned any steam coming off the outer surface of their dome, well here's some photos of the steam that came off mine. Just for reference, the designed in expansion cracks worked as the dome heated and expanded they opened and this morning with a residual dome temp of 94 to 96 degrees F the cracks have closed, maybe not completely but I expected some shrinkage.

Today I will fire again and over several hours in hopes that I will see no further steam rising from the dome. Then when it cools I will insulate for in my instance and I suspect for traditional WFOs one would be best advised to dry out completely before insulating. The first picture shows a darkening (wetting) where moisture collected around the expansion seams this in spite of the fact the mass is already in the high ninties. If the insulation was on the dome it would simply move to reside in the insulation, better in my opinion to get it out of the dome structure completely.

The third photo shows the size of the fire I had going for about 5 hours. At the end of which I had temps measured by IR thermometer of over 500 F at the top and 250 at the outer edge of the floor (hearth).

Wiley

[asudavew]

Re: Oven Curing

Very cool.

Great pics, and your oven is quite impressive!

Pizza soon?

[Wiley]

Re: Oven Curing

Dave, With any luck we'll have pizza tomorrow!
Today (in order to not waste the heat) we are going to give some ribs about 45 minutes roasting prior to throwing them on the regular grill.
Wiley

[asudavew]

Re: Oven Curing

Dave, With any luck we'll have pizza tomorrow!
Today (in order to not waste the heat) we are going to give some ribs about 45 minutes roasting prior to throwing them on the regular grill.
Wiley

Sounds scrumptious

Thanks for posting and keeping us to date.
It really is fun watching a different approach to achieve the same goal.

It will be interesting to see how it performs.. heat up times.. heat retention etc.

I wonder what the top of the dome will do when the fire hits 1000f.
Do you think it will glow red? Or is that hot enough?

I'm not a metal expert by any means..

DAve

[Wiley]

Re: Oven Curing

Dave, firing going as we write :-) First thing I notice today is that the seems that opened yesterday are the ones which opened straight away today. But I just jumped right in with a fairly decent fire.

I should have measured or photographed them but presently the oven seems to want to behave as if it were five distinct pieces. Top polyogonal, three side sections (all about the same area and mass) and a smaller piece directly behind the chimney transition (much smaller piece than the rest; if one divided a collar on a open necked shirt into three equal sections this would be the middle section ...the other ends of the collar are moving en mass with the side thirds of the main dome). Presently largest crack/split/openning/crevasse is about 1/8 inch. The interior temperature at top of dome has gone from 99 F at start to 651 F in one hour. The temperature of the hearth in a spot away from fire along side dome: start 79F one hour 280F. Exterior temp of top of dome is 134 so there is still alot of "soak" that can occur.

Oh and no steam being emitted from the concrete at present.

This is probably pretty boring for most, sorry :-|
Wiley

[asudavew]

Re: Oven Curing

Sounds like your expansion joints are working perfectly.
And since you don't have the normal brick mass holding in water, it may have already burned the water out.

I guess I missed this... How thick is your thermal layer on the outside of the metal dome?

[Wiley]

Re: Oven Curing

Dave, I did my best to have 4" over the covered portion of the dome. The mix I used was 5 to 1, crushed 1/4 minus basalt to Fondu cement. There are places where that thickness varies by perhaps 1/4" deviation highest to lowest, usually on the plus side.

Also as to your question regarding whether it would glow, I found this:

Temperature when metal glows red | Hearth Wiki

Perhaps it might but I think I will try to stay on the lower side of 1000F. At least for a while :-) so far my fires have not been the raging inferno I have seen posted perhaps after a while I will get there.... after I have some protection (insulation, render, etc) from flying hot pieces.

Wiley

[david s]

Re: Oven Curing

charcoal for curing is a good idea. What you want is burning coals rather than flame. Flame is much hotter and impinges directly on the dome interior wall giving you too much localized high temp heat, while glowing embers radiate a gentler heat evenly to the whole of the inside surface. I use what is known here is Aust. as heat beads. They are coal BBQ fuel and glow gently. Just throw them in on the few bits of wood you use for the curing fires.

[Jim Bob]

Re: Oven Curing

James,
If the variance on the temps from floor to dome are as much as 30-40 degrees difference(floor is hotter), won't I have a real problem in cooking various dishes including pizza? I won't know which temp to use. Question is how much variance is too much?

Haven't started cooking yet, but noticed this while I am curing the oven(6th day). Have been using lump charcoal to start fires. That may be causing excessive floor heat with no flame until wood catches fire.
Thanks,
Jim Bob

[christo]

Re: Oven Curing

Hi JimBob,

I'm not James but if you are in the 6th day of curing your oven has probably not stabilized yet. Though mine would cook pizzas after going through the drying stages, it took a couple to several firings to become predictiable.

I would feel up under the floor of my oven and it would be quite hot - I was bummed cause I thought I shoulda put more insulation in - now it's only warm to the touch after firing the oven for a couple hours. Same with hot spots on the outside - now she runs cool as a cucumber.

Hang in there - We all deal with the quirks of our oven - if after you feel your oven has stabilzed your floor is still too hot - there are ways you can deal with that - leave ash across the floor during firing or spread the fire out over the cooking area and move away when you start to cook.

You will make the best pizzas you ever had! (and the best bread, crab mushrooms, turkey, beef brisket...)


Christo

P.S. Please take pictures of your first Big Scary Fire. I love those!!!

[Jim Bob]

Re: Oven Curing

Christo,
Great to hear from you on this. Just left my oven. It made it to 650 and i just quit firing. I will give it another couple of nites to make it to 800. But, that temp was the floor. The dome was a full 210 degrees cooler according to my probe. Now that is quite a difference. But the entire dome did turn white, so I am feel like the dome probe must be off. Don't believe it will burn the soot off at 440.
But, I am excited about cooking on it, just don't want to rush it. No cracks yet!!
Jim Bob