Oven Curing

[Wheels1974]

Re: Oven Curing

It was good to see those photo's and to me it looks as though the cast had a flaw, whether it is air caught up within the cast or something else to do with a flaw in the cast. After looking at those photo's I'd bet that it's a manufacturing problem and nothing to do with the way you cured the oven. It's such a shame because there are so many.

[james]

Re: Oven Curing

Hi Ed,

Those are voids (little air pockets) which are imperfections from the casting process. The dome was not vibrated sufficiently -- though we have strict production standards and this is the first time I have seen this.

The good news is that they are only cosmetic, and they won't have any negative impact on the way your oven cooks, and or how long it will last. The depth of the holes is not significant relative to the mass of the refractory dome.

If you have any questions or want to talk about this a little more, send me an email at james at fornobravo.com. We want to be sure you are confident and happy!
James

[elecco]

Re: Oven Curing

Hi Ed,

Those are voids (little air pockets) which are imperfections from the casting process. The dome was not vibrated sufficiently -- though we have strict production standards and this is the first time I have seen this.

The good news is that they are only cosmetic, and they won't have any negative impact on the way your oven cooks, and or how long it will last. The depth of the holes is not significant relative to the mass of the refractory dome.

If you have any questions or want to talk about this a little more, send me an email at james at fornobravo.com. We want to be sure you are confident and happy!
James

Thanks James (and everyone else that replied),

I'm feeling much better about this.

James - I'll follow-up with you direct via email.

~Ed

[coladipietro]

Re: Oven Curing

James,

I'm sure this information is posted in here but must have missed it. When burning the curing fires, what is the gauge of temp? For example, with the first fire at 100 degrees, do you measure air temp or brick temperature? Thanks for your insight and for the great forum!

[SCChris]

Re: Oven Curing

I used the dome temp. Just remember, go slow on the curing. Also remember how much effort you have into the oven at this point.

Chris

[ErFornaio]

Re: Oven Curing

Day Four of curing my casa2g100 that I purchased at FB about a month ago. Started with some suggestions so I put a heat lamp in the oven to cure over a day or two after having let it sit for two weeks. Then on Thursday I did the 300 degree fire, followed by a 350, 400 and today on a 450. Everything seems good.

We've been firing it from 8am to 6pm and then closing it off overnight. Temperature seems to drop to about 1/2 of what you leave it at the night before. I am amazed at how well it retains heat compared to my failed Pompeii oven build from last year.

Tomorrow is supposed to be my 500 deg firing, but not sure that I will be able to do that until tuesday. In the instructions it is the last one. Should I go a few more? I have usually cooked at about 750 on the floor, so that would make my dome need about 900 degrees (well on the old oven).

One question, when getting the temperature up, the flame sometimes spiked and touched the dome. My IR thermometer read above the suggested temp for the day. However, spreading the fire and dampening the flame dropped that temp very quickly (we're talking seconds, not minutes at higher temps). Is that an issue?

All in all, very pleased with this build. Just trying to ensure there are no cracks that would ruin the oven. On one section, there seem to be a few spiderlike lines running off from one of those small holes in the cast, but they are super thin, plus the temperature never went over 250 there in the first two days (lower side of the oven), so I am not very worried.

Now, to get the last few firings done, and the cosmetic work finished....

[SCChris]

Re: Oven Curing

Er,
I think you'll be fine with the momentary spikes, and since your running 10 hour burns I think you're double good..

Something I noticed when I cured, was the oven becoming much more responsive to heating. In the beginning it seemed to take a very long time to come to the target temps as time went on and the oven dryed, I had to be careful not to pass the target temp point..

You are really close now. One or two good burns and you should be gold to go hot. After I finished my curing on my next 10 or so burns I still built the fires slowly. I mostly feared thermal shock during this period. I don't know if it was overkill but I know most people notice the oven settling in for the first 10 or so burns.

Chris

[ErFornaio]

Re: Oven Curing

Day 5 has come and gone.... Fired up to 500.

Looked into the oven to see what the cracks are looking like. Thankfully I don't see any major ones. I can't however see the bands over the seams of the Casa2g as the insulation and stucco are already over it. There are a couple of those pocks where the cast somehow didn't manage to fill in mortar. I'm hoping those won't be a problem and I haven't seen any cracking in them so I am hopeful.

Temperature dropped from 500 to 245 overnight.... Still liking the retained heat, and hopefully that will get better.

Today we plan on doing a 700 or so burn, but just for about 6 hours. We don't have the time to do the full ten hour burn we've been doing.

[ErFornaio]

Re: Oven Curing

Well (insert disappointed face here)... after following James and FornoBravo's instructions to the proverbial T, I still have a significant crack in the back section of my Casa2G100. I notice it only when fully fired and it can't be even 1/32" wide, but it's there. Runs from one edge straight line towards the middle. I can't tell if it is running through to the outside of the oven because of the stucco outside. I can, however, tell that it's getting longer. There's also a vertical line in the same section. I originally thought that it was just an imperfection in the cast, but the more I look at it, the more I wonder if it is a long crack. The two cracks are meeting up.

I couldn't have possibly cured the oven any better than we have done. It was a long two week process. I am very upset by the result... I'll take pictures tomorrow morning and post them.

[david s]

Re: Oven Curing

does the Casa include stainless steel needle reinforcing in the manufacture?

[fxpose]

Re: Oven Curing

I'm just about ready to start fire curing my oven and since I have on hand several large bags of charcoal briquettes I decided to use them instead of making a series of small wood fires. I am going to use The Minion Method for Lighting Charcoal for sustained low temp fires like I do when cooking low and slow. I will close off the entry to allow just enough air in and exhaust out for the slow burn.

George

[jmhepworth]

Re: Oven Curing

I really think it's wise to go low and slow. I have cracks (expansion joints) that I wish I didn't have.

[fxpose]

Re: Oven Curing

Well, I used the minion method and piled a Weber chimney full worth of charcoal briquettes and dumped them in the oven last night and tried to regulated the temp between 200 to 250F by blocking most of the airflow into the oven. I was able to stay within those temps and this morning, a full 12 hours later the briquettes were still glowing and the temps were still within range. I piled on a just a handfull more briquettes before going to work to run the temp for a few more hours.
But for the very large amounts of ash the briquettes leave behind, I like using them.

Come to think of it, I could have thrown a pork butt in there last night for some carnitas for tonight......

George

[doobie dee]

Re: Oven Curing

I'm starting to cure the oven. I don't have the insulating blanket on yet. Should I have put that on before I started? Also, may be a dumb question but where do I measure the temp? I have one of those dual temp gauges (probe for the meat and probe for the smoker) in the oven and also a laser temp gauge. As I was doing the initial fire with paper only, the top of the oven was going to about 250 while the rest of the oven was slowing rising. I was able to get the dual gauge up to about 170 degrees and started noticing a crack in the arch, but nothing inside, so I stopped for the day. Can anyone help with whether or not I should insulate first, and also where to measure the temperature? Thanks friends.

[SCChris]

Re: Oven Curing

Hey doobie,
Some insulate before and some do not. Here is my take and what I did. Before I insulated, I ran a quartz shop lamp in the dome full time. This lamp allowed me to bring the inside top of the dome to about 140. I blocked the entrance, at night, to help maintain these temps but would allow some air in and out during the day to help clear the warm moist air. After several days, a week??, of this I started using fire to bring the temps up further. I think I finally added the insulation around the dome at about 250 measuring on the inside of the dome. My reasoning was that I wanted to drive most of the water out before applying insulation so I would keep the insulation dry. One area that I was concerned about was uneven heating of the dome and consequently uneven expansion and cracking. There have been some examples of clay chimney flues cracking because of uneven heating or at least uneven heat was felt to a contributor to the cracking. Some cracks are likely at this point, not to worry. My guess is that everybody gets cracks, only some sub-set of these people notice the cracks.

Chris

PS Slow and steady is the name of the game when curing.