Cure before insulating?

[whocanitbenow]

I noticed that the FB plans seem to have the curing come at the very end. However, a few people on the forum mentioned that they cured prior to insulating the dome. Does anyone have any thoughts/experience on which is preferable?

For insulation, I plan to use the insulfrax blanket followed by some concrete and waterproof stucco. Does this affect the choice to cure beforehand?

Here's a pic of my progress so far:

[oventhusiast]

Re: Cure before insulating?

Good Question!
I was wondering the same thing while reading the Pompeii plans.
Rick

[RTflorida]

Re: Cure before insulating?

I'll second that......actually, I posed this exact question on an insulation thread a couple of weeks ago, with no response. I too have read both - curing before or after insulation. Don't know what the majority on the forum thinks. I have since moved forward and insulated my dome without curing; weather permiting, I plan to begin curing fires on Saturday (wish me luck). After the curing I plan to seal coat it with stucco and finish with mosaic tile...sure hope there isn't any cracking at that stage

RT

[jahysea]

Re: Cure before insulating?

My opinion is that curing before insulating is a great idea.

Regardless of your masonry skills and the time you allow before curing, you may find that your oven cracks a bit during curing or with heat expansion from a large fire.

If you haven't insulated yet, you can see those cracks and fill them with a flexible heat rated caulk to prevent smoke and hot air from leaking into your insulation.

One problem with this approach is that if you are planning on using a wet portland/perlite or similar mix for insulation, you will wet the oven and set yourself up for another round of curing fires. You wouldn't have this issue with the insulfrax blanket and dry insulation.

I built a "house" around mine and used insulfrax and dry insulation.

RT, good luck with no cracks in the Stucco, you will be far ahead of me if it ends up that way. Mine's had some hairline cracks. I still haven't painted it, waiting for alllll the cracks to come out.. BTW, I found much less cracking when I switched to a premixed stucco product that had fiberglass fibers in it. Wasn't any different to apply, but it cracked less.

[CanuckJim]

Re: Cure before insulating?

JC,

Don't know what the majority opinion is on curing, but I'd have to agree that curing before insulating is a very sound idea for the reasons you outline. If wet insulation is used, you do have to be a bit careful with start up, as you say. Let's not forget that curing has to do with driving off water, sure, but it's also about the chemical process of cement hardening. You can do it with heat, but time in a protected environment is the best process. It takes at least 28 days for concrete to cure properly, to the right hardness factor. Taking shortcuts will weaken the structure, and that leads to cracks.

No matter how this is done, curing fires are still a must. The oven plans outline that procedure quite well.

It's agonizing to wait before start up, I know, but new builders should possess themselves of patience before pizza if they want their ovens to last.

Jim