Another Minneapolis WFO

[Sixto]

Thanks Russell and MarkI believe you, but I wish I had of those "invisible cracks" that some ovens get...
I will get over my disappointment tomorrow, and build even slower, more distributed fires for the rest of the week.
Even though it got as high as 600F today, i will also stick to the schedule and try to stay close to 500f tomorrow.

[MarkJerling]

Yup. there are two types of ovens: Those with cracks and those who's owners can't see the cracks. Don't sweat it Sixto

[UtahBeehiver]

Every oven cracks somewhere. If a builder says their oven hasn't cracked then they should go into politics or sell use cars.

[Sixto]

Well, I wasn't trying to rush or anything, but I guess I went too far. Today's temp goal was 400F.
I started with charcoal briquets, was up to about 250f, so I added some sticks that were 6" long by 1" wide. (like Russell said - one stick too many can send it over the edge)
Then the temperature spiked from 300F to 600F in a matter of seconds.
I spread the coals around the dome to cool it down, and make the heat less concentrated - but as you can see below, a 1mm crack appeared at the top of the dome arch.
Not the end of the world, but disappointing after trying to be as cautious as I could.
Oh well.... I will wait till it cools down further and hope the crack doesnt go too far up on the inside of the dome....

I guess the lessons here are to add 1 stick at a time, wait 3-5 minutes, and if more heat is desired, add ONLY ONE more stick, and wait 3-5 mins each time.
Be ready at all times to spread the coals, especially as you start to approach Pizza Temps (400F and higher).
At these temps, I'd rather even out the heat throughout the dome, than to keep it concentrated in the middle.

[UtahBeehiver]

New oven will smoke a lot until cured.

[Sixto]

FIRE IN THE HOLE! (Day 2)

Took my time building up to temp, but it got a little hotter anyways - 316F, no harm done. Temp was down below 300F in a few minutes. The best news is that even without an insulated door (just bricking up the opening) the inside of the dome was 86f, while the ambient temperature was 52f this morning at around 8:00 a.m. (a day after the first fire to 200F)

The oven still smokes a bit out the front of the gallery vault, but less than yesterday.
The soot inside the dome is not clearing anywhere yet.
I need a shower to get the wood smoke smell out of my hair...

[Sixto]

Once the starts really drying out, the black soot will begin to burn off at the crown of the dome (this happens at around 300C) If you shoot a temp at the base of the dome you will find that it's barely 200C and it's this difference in temperatures ,which also mean difference in thermal expansion, That can be damaging. Slowly the white will extend down the dome, but there is often a persistent ring of black around the base of the dome. This is an indication of cooler temperature there, so instead of making the fire bigger try spreading it out so there's less flame impingement on the top of the dome, but more at the base. You're done when the whole dome has turned white.Then you are ready to add the outer render layer(s)

Perfect, thanks for adding all the detail above, I will go slow and keep an eye on the color of the dome interior.

[david s]

Great result. Be careful and patient because now is the time builders get excited and hurry things along with damaging results. Almost there, don't sprint to the line.
Once the starts really drying out, the black soot will begin to burn off at the crown of the dome (this happens at around 300C) If you shoot a temp at the base of the dome you will find that it's barely 200C and it's this difference in temperatures ,which also mean difference in thermal expansion, That can be damaging. Slowly the white will extend down the dome, but there is often a persistent ring of black around the base of the dome. This is an indication of cooler temperature there, so instead of making the fire bigger try spreading it out so there's less flame impingement on the top of the dome, but more at the base. You're done when the whole dome has turned white.Then you are ready to add the outer render layer(s)

[Sixto]

UtahBeehiver (I responded to your P.S. via private message) Yes, I feel more confident about being able to control temperatures after today.... Starting with charcoal briquets was easy, and adding small pieces of kindling about 1" in diameter and 4" to 6" long seem to be a good way to build up slowly.

[UtahBeehiver]

Great curing start, be patient. This is where we see some builders say one more log won't hurt and it spikes the temp and causes cracking. If you see steam you are running too hot too fast. Look for condensation under the plastic which indicates mechanical water is still present in the oven.

PS where in Minneapolis, have a step son in White Bear

[Sixto]

FIRE IN THE HOLE!

Today we successfully started the drying fires... Weather this morning is partly cloudy, dry, and about 60F.

• First order of business was to move the tent away, add the stainless flue extension, get some charcoal briquets white hot and heat up the chimney.
• Second, I tried spreading the coals around in smaller groups but that only got the dome to about 100F
• Next I moved all the coals to the center and added some kindling.... that got me to around 155F

• Finally, after adding even more dry kindling to the coals, I reached the temp goal for day 1 - around 200F at the top of the dome, and cooler below as I aimed the infrared thermometer around the inside of the dome.
• Then I bricked-up the opening to smother the fire and let the heat even out throughout the dome. The whole process took me about 1 hr. but I was fussing a lot, Tomorrow I will know more what to expect and should be able to do it quicker.

Some observations from day 1. Depending on how the wind is blowing, some smoke still comes out the front, I'm playing with arranging bricks at the opening to help the airflow inside the dome circulate and stratify, so the smoke is at the top 4" of the arch. We'll see how the airflow progresses as the dome and flue get steadily hotter.

The outside face of the top brick in the arch got to 100F. The stucco on the gallery is in good shape, still curing, since it has moisture on the inside face of the clear shrink-wrap covering, but that area never got hotter than ambient temps and neither did the perlcrete, which is looking nice and dry.

[Sixto]

Yes, I hope my week-2 pizzas are worthy of the ocassion! I just have to remember this is not about me and my projects, it's about my son and his bride, so I'll do the best I can and enjoy the outcome as if it were just another step in the process....

Speaking of process, today was a long, hot day of mixing and applying stucco to the gallery vault. 2 layers of AR Fiber Mesh are embedded into roughly 1" of homemade stucco - 4 parts mason sand, 1 part Portland Cement, 1 part Hydrated Lime, 1 part water and 1/3 part of Quickrete Concrete Fortifier for improved adhesion and water resistance. The whole thing is now covered in shrink-wrap, and I removed the plastic off the perlcrete to help it dry faster...some of the stuff I put-on 4 days ago was still wet.

Can't wait to start the drying fires.

[MarkJerling]

Wedding pizzas! Sounds like fun. Enjoy!

[Sixto]

This is project management at it's best!! 24/09, excellent planning!

Thanks! some skills are useful even beyond retirement, but honestly, I though I was DONE making Gantt charts and my life was going to be one big improvisation! "Best laid plans!!!"
I guess now that's in writiing, the pressure is on - I only have 2 weeks between the first Pizza and my son's wedding. I better learn to work the oven fast!

[Mr. Slowhand]

This is project management at it's best!! 24/09, excellent planning!