Curing my 42" low dome oven

[builder brad]

8 hours yesterday, starting with a small fire that got progressively bigger!

I got a bit confused with the new temperature guides as I was taking readings from the 5 thermocouples and not air temps, although the first couple of hours did not even put any heat into the actual bricks.

at the highest point, just before I put the door on once the fire had died down I was getting 300 celcius on the floor at the centre, 110 in the dome and 80 outside the dome between the bricks and insulation.

I have between 3-4 inches of blanket on the sides and 5-6 inches on the top of the dome which got rained on heavily last night before the first fire. I have a tarpalin over the dome now which is wet with condensation that the fire is driving out.

NO CRACKS, so far. anything that I do get should be superficial as all of my bricks were cut to fit except the first 2 courses.

I am keeing an eye on my flue as it was cast out of cement, clay powder from the brick cutting and shapt sand, with a 3mm wire mesh framework.

Brad

[builder brad]

Re: Curing my 42" low dome oven

day 2

started at 6.30 am

just a little more info on my oven. I have cut every brick to fit from the 2nd course and used an air dry thin bed cement - Sairset and Superplastic. As I had a lot of brick dust I used this to make up a mortar to cover my dome with about 1/2 inch on the top and half way down the sides - this is definately not structural although I kept spraying it with water for 10 days and covered during its wet cure.

dome had dropped to 50 celcius overnight - I guess that wet blanket will work better when its dry!

built up slowly again as yesterday, but its windy here and I get less smoke in my face with a bigger fire, so I managed to get 211 in the dome about 1/2 an hour ago. I have let things die down a little and am now getting 207 now with 336 in the hearth, near the surface which is over 600F.

Should I worry about the high hearth temps? There is certainly some moisture in those bricks, but nothing to cure.

I can smell damp cement.

[builder brad]

Re: Curing my 42" low dome oven

its dinner time!

just after 6.00 in the evening-fire has been going all day, day 2 of the cure, and the dome surface is 200 degrees C near the top with the thermocouple on the outside of the dome reading 196 degrees, so we are starting to get full saturation.

I was going to cook cod loins wrapped in parma ham tonight with a garlic, salted caper and tomato paste and add a couple of eggs into the crockery dish 10 minutes before the end - in my electic oven?. Then I realised that I could use the other one! just because its curing does not mean I cannot use it.

Brad

[asudavew]

Re: Curing my 42" low dome oven

its dinner time!

jThen I realised that I could use the other one! just because its curing does not mean I cannot use it.

Brad

Now you are starting to think like a WFOer.

Congrats on your build and take your time with the curing.

Dave

[builder brad]

Re: Curing my 42" low dome oven

Day 3 6am

6 am this morning

top dome 182C
Exterior of dome 194C
Near surface Hearth 186C
Deep Hearth 206C
Bottom of Base between insulation and Hearth 59C

and this was without a door, just a few loose bricks

[builder brad]

Re: Curing my 42" low dome oven

Cheers Dave

I am going to keep the fire going all week - if I can!

[builder brad]

Re: Curing my 42" low dome oven

day 3

been going all day now from early this morning - at least 12 hours running around 250C in all the burried thermocouples.

About an hour ago I started to put on some 12" long pieces of 4" thick willow that is relatively damp, so I was not worried about going to ""plasma" with this stuff. Most has now burnt down to ash and I have the following temp readings:

top dome 302C
Exterior of dome 258C
Near surface Hearth 372C
Deep Hearth 285C
Bottom of Base between insulation and Hearth 258C

for the first time the outside of the vent is too hot to touch!

looking good.

Brad

[james]

Re: Curing my 42" low dome oven

This is looking good. Are you going the roast a chicken and some potatoes tonight? :-)

James

[builder brad]

Re: Curing my 42" low dome oven

Cheers James,

not sure about using the oven properly yet - I had to switch the cod dish over to my electric oven when my wife came back from the gym hungry. The cod had been in the oven an hour and was just starting to cook!

I guess that the actual air temps on that 2nd day were not as high as I thought, regardless of the readings from the Thermocouples. When I pt my hand inside the electric oven to take the fish out 200C felt lots hotter than the temperature in my oven, even yesterday only felt similar when I was hitting 370 celcisus in the hearth. I guess the airflow can make the hand feel cooler.

Its getting really hot now though. Day 4 - 7 am start. The bricks that I have used to close the opening are too hot to remove easily, the ceramic board placed in front of them is scorched and the fire is still smoldering. I relight in 30 seconds using some of the dried wood from inside the dome that is still smoldering.

temps this morning are:

top dome 252C
Exterior of dome 262C
Near surface Hearth 260C
Deep Hearth 246C
Bottom of Base between insulation and Hearth 76C

are these numbers any good?

Brad

[james]

Re: Curing my 42" low dome oven

Brad,

I think you are there. Try turning it up a bit (though not crazy) and see what she does.

What does your hand tell you? If you can hold your hand inside the oven for 4-odd seconds, you are still not getting into pizza heat.

James

[builder brad]

Re: Curing my 42" low dome oven

There were times yesterday when I could really feel the heat in my face and when I was placing pieces of wood on the hearth I could almost feel the hairs on the back of my hand burning.

One time I loaded a pile of really dry pine strips in and the flames were licking all around the inside of the dome. I had to spread the wood out on the floor to stop it from going into overdrive! and then I knew it was HOT. I also noticed that almost all of the soot had burned off of the inside of the dome.

Lets see what I can top out at later today!

here are the temps right now:

top dome 240C
Exterior of dome 247C
Near surface Hearth 213C
Deep Hearth 207C
Bottom of Base between insulation and Hearth 74C

so even with the small fire going all morning I have lost heat by opening up the bricked in door. The lower hearth temps are probably because of the amount of ash covering it.

Brad

[builder brad]

Re: Curing my 42" low dome oven

DAY 5!

I blocked up the door overnight with a piece of 2mm thick stainless steel cut to fit into the opening perfectly, with a couple of mm gap in places at the most around the edges. Then I put some of the off-cut ceramic board in the opening.

temps this morning:
top dome 255C
Exterior of dome 257C
Near surface Hearth 208C
Deep Hearth 214C
Bottom of Base between insulation and Hearth 76C

I just added some more wood, and it lit from the smouldering embers!

[builder brad]

Re: Curing my 42" low dome oven

OK

bank holiday weekend over........almost. I am writing this on Monday evening 10.30pm.

I have really tried to push the oven over the last couple of nights, and have maneaged to get the interior of he dome to clear completely of the black soot, however the thermocuples have never gone over 400C. The most frustrating thing tonight was trying to hit 500C from a cold start and after 3 hours getting to 350 with everyone asking when we could use the oven.

the thing is I am using wood that has not been properly dried, bought from a neighbour planning for his winter, and I needed to use a hairdrier and baffle plate to give the fire a BIG kick start.

everyone has now gone home and my wife is in bed - I have just reached 430 Celcius and cooked the best pizza of the weekend, but I have eaten it on my own. I did not really get to eat as I was chopping wood ect.

Pleas tell me this is going t get easier.

Brad

[egalecki]

Re: Curing my 42" low dome oven

I don't know how much easier it gets when your wood isn't as dry as it ought to be, but with proper wood it does indeed get easier. The first time I took my oven up all the way it took forever. The second time was faster. I think there's a lot of moisture in there even after the week long cure, and as it leaves, it gets easier to start a fire as well as get it up to temp. My oven was so damp inside at first it was hard to even get a fire started, much less keep it burning and get the oven hot!

Patience....

[Frances]

Re: Curing my 42" low dome oven

You'll fnd the weather influences your oven, too. After a long dry spell its far easier to get the oven up to temp than after a week of rain.

The bit that gets easier is the planning. As you get to know the oven better you can guess at how long it'll take on a certain day and start firing accordingly. You'll probably also get better at grabbing a slice of pizza inbetween cooking for everyone else...