Order of Operations: Chimney, Back Wall, and Foam Removal

I have read all of the threads about each of these operations, and while I think I have a solid plan, I thought I would start a new thread to tie things together (pun intended).

The directions call for closing the back, then building the chimney, then removing the form. An emerging, popular, and maybe preferred sequence seems to be building the chimney, removing the foam (after sufficient drying time), and closing the back.

I finished my arch yesterday, and my plan is to lay the chimney today then leave my oven alone for 9 days, when I return from moving a daughter to VA. Of course, I am dying to take out the form, and could do so as late as Saturday (4 days of drying time) before we leave, but the trip provides a natural and forced break for a good stretch of drying. I would then remove the form and close the back after the arch and chimney have been drying for 9 days.

So, my sequence would be: lay the chimney with the form in place - leave the arch and chimney to dry for 9 days - remove the form - close the back.

I know my planned sequence does not follow the Brickwood directions, but there seems to be a good amount of thought and success behind changing up the steps, especially with sufficient drying time.

As always, I appreciate all the help this forum provides!

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I read all that advice avidly too. But I ended up closing up the back (and bricking the chimney) before I took out the mold. We let it dry post-stucco for about 10 days, and the foam came out very easily (maybe 15 minutes of tugging with a crowbar),. We did use a ton of Pam as we laid the bricks. So instructions 1.0 really do work too!

Thanks! It’s good to hear about successes with different strategies. I also used a good amount of olive oil though I did occasionally forget to oil up the spot for a brick here and there.
Thanks, again!

Hi, Bill! Makes ya feel like a bit of a rebel to pull out the foam first. :slight_smile:

But as Serena says, the “orthodox” directions work, too. I ended up building the back wall first, and while it was a bit more awkward to get at the foam in the back of the oven, it came out just fine.

What you’ve done also works fine, because the form has absolutely nothing to do with the back wall. It’s critical for the arch and the chimney, but that’s it.

I know that @BrickWood is working diligently on Directions 2.0, and I hope he includes the option to sequence the back wall build as you are doing. It’s a conundrum, because the form is the “secret sauce” for this build—but extracting it does not always go smoothly.

Oiling it and keeping it accessible for removal are tips that I’m sure he’d want to include in the next edition.

Good luck with finishing your build!

The only advantage you will have pulling the form before the back wall is done is the it might be easier to get it out. I took my form out as directed after stucco stage was complete. It gave me about two weeks of cure time. To me it was giving all the mortar joints as much time to cure. I thought it was best to have patience for it could be benifical in the long run. But that’s just me.

Othe people have had success following the new method. Your call.

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Thanks for taking the time to respond with your experience and approach. It all helps!

Got back from moving daughter at midnight and took the form out at 7:45 this morning. A bit of careful and methodical tapping and some very low-level persuasion with a flat bar on the bottom of one side, and the form came out in one, nearly pristine piece. The olive oil was definitely a key factor in the easy removal.
Now that I inspect my arch on the inside, like many others, I have some spots where there are minor voids in the interior joints. I was hoping that every joint would have been completely filled, but the voids are very shallow and probably represent less than 10% of all the joints.
Back wall today!

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You have a well cured arch, and it sounds like the olive oil really worked well for you.

I know you are heeding the strong caution to not fill those voids, but to others tempted to fill them: don’t. Especially in the overhead areas, you have lots of mortar in there already. Anything you add can and will fall out at the worst possible moment, and passing off a rock-hard mortar fragment as an olive pit won’t cut it.

Thanks for the report Bill, and good luck with your back wall!