Little Confused?? When to cure oven?

[rbigante]

I have just finished constructing the dome & opening portion of my 36" oven. I'll be constructing the entry and chimney opening hopefully tomorrow weather permitting.

I did some searching but couldn't find the answer I was looking for. My question is this:

Should I insulate the exterior of the dome then performing the curing fires or should I perform the curing fires then insulate exterior????? Does it matter which I do first???? I plan on enclosing with metal studs and cement board for a cultured stone finish.

Any advice is appreciated. Thanks, Rino

[Calabrese]

Re: Little Confused?? When to cure oven?

Hi Reno
I was wondering the same thing. I'm leaving the insulation off while I cure. I'm sure any cracks will be just as evident without taking the insulation off and on, plus the insulation is a possible cancer hazard if inhaled and may be irratating to your skin, eyes and respiratory tracked. I only want handle this stuff once so either way wear gloves, goggles and a good respirator.

Regards Joe
Mississauga, Canada

[david s]

Re: Little Confused?? When to cure oven?

I think that the outside temperature is the controlling factor to this question. You are trying to eliminate moisture from the floor and dome. Without the insulation the moisture has a better chance of escaping, but your oven will cool down really quickly especially if the outside temp is pretty cold. With the insulation on the moisture will tend to be trapped in the blanket, but it will hold the heat in longer. Either way is ok although without the insulation on gives you a chance to inspect the dome for any development of cracksand subsequent patch up before continuing.

[dmun]

Re: Little Confused?? When to cure oven?

The argument for insulating before curing is that you'll have less extreme temperature differences between the inside and the outside of the dome, and less chances of cracking from this differential. You also drive out the water from the insulation.

That said, folks have done it both ways. It doesn't seem to make that much difference, and no curing method seems to entirely avoid cracks.

[rbigante]

Re: Little Confused?? When to cure oven?

I figured the moisture has a better chance to escape without the insulation in place. I'm not too worried about cracks. I think I'll give it a try without the insulation.

thanks for everyone's input

[dmun]

Re: Little Confused?? When to cure oven?

I figured the moisture has a better chance to escape without the insulation in place.

The insulation is pretty porous, and contains moisture of it's own. It won't be trapping anything unless you've sealed it in with stucco.

[rbigante]

Re: Little Confused?? When to cure oven?

dmun, are you referring to the vermicrete insulation? I should have been a little clearer. I'm using 2" of FB Blanket, framing with metal studs and filling voids with loose vermiculite. I wouldn't imagine that the FB Blanket will contain much moisture but I'm not 100% sure though

[dmun]

Re: Little Confused?? When to cure oven?

I wouldn't imagine that the FB Blanket will contain much moisture

You're right - just atmospheric moisture, and anything it soaks up from the dome

[Neil2]

Re: Little Confused?? When to cure oven?

I would vote for putting on the insulation before curing.

[rbigante]

Re: Little Confused?? When to cure oven?

Neil2, any particular reason??

[Frances]

Re: Little Confused?? When to cure oven?

Bsically both methods work fine, so I think you should do whatever suits your time schedule and inclination best...

I fired mine up without insulation because I was in a race against the incoming Winter and it all cured perfectly well with only very minimal cracking.

[Neil2]

Re: Little Confused?? When to cure oven?

Keeps the heat in the brickwork. Apart from driving out moisture, curing is also the final firing of the refractory mortar.

[Dino_Pizza]

Re: Little Confused?? When to cure oven?

Incoming silly question:
When you say things like "there will always be cracks", are these cracks along mortar joints? We're not talking about cracks in the brick are we? The Refmix I used seems stronger than brick, so I can't imagine a crack but I just want to know if these small hair line cracks are usually just in the mortar. Thanks, Dino

[Les]

Re: Little Confused?? When to cure oven?

I just want to know if these small hair line cracks are usually just in the mortar.

Dino,

The cracks (usually) appear where the mortar bonds with the brick. If they are small, no worries.

Les...