insulate before curing

[waynespizzaworld]

On my first oven I did the slow cure before I put the insulation on. I have noticed on my updated instructions for the build of the Pompeii that it is recommended to wait one week after the oven is completed.

Does this mean after insulation is on and also stucco?

I was hoping to put on the insulation (3 x one inch inslulating blanket) and then put on the first coat of stucco. This would bring me to 5 days or so after the brick work is complete, then I would start the oven cure for 5 days while the first coat of stucco also cures. Then I could put on the top coat of stucco and a few more days of curing and then pizza time.

Does this sound like a reasonable approach?

Looking at my pictures from my last build I see I cured before insulation was put in place and all was well. No big cracks after about 3 years of use. I am guessing the instructions have changed since the pdf files were first sent out but maybe I just did not read into them properly.

Thanks Wayne

[david s]

Re: insulate before curing

"I was hoping to put on the insulation (3 x one inch inslulating blanket) and then put on the first coat of stucco. This would bring me to 5 days or so after the brick work is complete, then I would start the oven cure for 5 days while the first coat of stucco also cures. Then I could put on the top coat of stucco and a few more days of curing and then pizza time."

Given that you should keep the stucco damp for a week to increase its strength, I think it is probably better to cure the oven before doing the stucco. Any build up of steam in the insulation layer can produce enough pressure to crack the outer shell (water increases by 1000 times when it turns to steam). For an igloo I think it"s best to cure after placing the blanket then do the outer shell and keep it damp by wrapping in plastic for a week, before proceeding with more fires. But there is more than one way to skin a cat and other no doubt others will chime in with their method.

[david s]

Re: insulate before curing

"wait one week after the oven is completed."

I think this means after the brick dome is completed. Assuming the one week gives the mortar a chance to cure and also using the weather to remove some of the moisture before driving it out with fire. Personally I believe that waiting even longer is probably better given that the homebrew contains quite a bit of lime which slows the curing process down. The trouble is that when you get to this stage you start getting excited and want to push on and get it finished.

[brickie in oz]

Re: insulate before curing

you should keep the stucco damp for a week to increase its strength,

The idea of keeping cement based products damp applies to hi end concrete structures, like bridges, dams, hi rise buildings etc.

I cant see the relevance to a backyard oven?

[david s]

Re: insulate before curing

It applies to anything made with Portland cement.

[brickie in oz]

Re: insulate before curing

True but the relevance for added strength is not needed in an oven.

Edit:
I work with Portland cement day in day out, when the temp gauge hits 30 to 40c the brickwork Ive laid is as hard a stone within a week with no babying of the mortar.

[david s]

Re: insulate before curing

Fast drying render is prone to cracking.This can be alleviated by keeping it moist. It takes 28 days to get to full strength. Check this link for advice from the experts.
Cement Render | Texture Coatings | Solid Plastering

[brickie in oz]

Re: insulate before curing

Fast drying render is prone to cracking.This can be alleviated by keeping it moist. It takes 28 days to get to full strength. Check this link for advice from the experts.
Cement Render | Texture Coatings | Solid Plastering

Unless you have forgotten, I am one of them experts that work day in day out with cement based products.

Mortar cracks when high clay content sand is used, its the clay that shrinks to form the cracks.

You really are scraping the google barrel to come up with that link.
What makes you think they are the experts?

[david s]

Re: insulate before curing

Actually the outer shell of an igloo oven is more akin to ferro cement construction. Try any of those links and they all recommend keeping the work moist.

[brickie in oz]

Re: insulate before curing

Listen to Davids he is the expert in the field, not me.
Ill crawl back into my box now.

[Neil2]

Re: insulate before curing

As Thomas Watson, founder of IBM once said:

"If I have two engineers who agree on absolutely everything, then I can get rid of one of them."

[Faith In Virginia]

Re: insulate before curing

I did, Built the oven let it set for about 2 weeks did some curing fires then put on the insulation.

Engineers if an engineer asks me to do work for them I charge them double. They always know more about your job then you do.

[lwood]

Re: insulate before curing

That's pretty harsh on Engineers, I'm pretty sure we have lots of Engineers on the forum besides myself.

[waynespizzaworld]

Re: insulate before curing

Thinking about things I don't think it matters all that much if the insulation is on or not. I will put on the insulation first before curing.

But I guess my main question is will it be ok to cure the oven just after I put on the stucco. My concern with all the water coming out of the pour of the brick it may effect the stucco.

It will let me get cooking one week sooner if I can start the curing process at the same time as laying the stucco down.

I hope this is an OK approach.

Thanks for this .................Wayne

[dmun]

Re: insulate before curing

But I guess my main question is will it be ok to cure the oven just after I put on the stucco. My concern with all the water coming out of the pour of the brick it may effect the stucco.

If, and this is a big if, the stucco seals against water coming in, it will also seal against water getting out. This may make your drying-out process a long, drawn out one.