Curing times

[angelboy]

I build the inner brick dome about a month ago and did 5 days of firing, cooking on the 6th day. There was some hairline cracks that opened up to about 1mm when the fire was hot (800F).

Last weekend I applied the ceramic blanket and then the perlite igloo shell. It's had the last 5 days drying out in the sun.

Being in mind I've already cured the dome, what would you suggest as an appropriate curing process for the shell?

I want to cook a pizza on Saturday (5 days) when my daughter comes over for the weekend.

[david s]

I build the inner brick dome about a month ago and did 5 days of firing, cooking on the 6th day. There was some hairline cracks that opened up to about 1mm when the fire was hot (800F).

Last weekend I applied the ceramic blanket and then the perlite igloo shell. It's had the last 5 days drying out in the sun.

Being in mind I've already cured the dome, what would you suggest as an appropriate curing process for the shell?

I want to cook a pizza on Saturday (5 days) when my daughter comes over for the weekend.

Unfortunately firing an uninsulated oven often results in cracks developing, because of the huge difference in inside and outside temperatures which leads to uneven thermal expansion. This situation is largely remediated by insulation which evens out the applied heat. Don't worry about the cracks as the hemisphere is a self supporting structure and can't collapse. It will have no bearing on the oven's performance and the cracks are unlikely (but no guarantees) to get any worse.Depending on the thickness of the perlcrete layer and the weather drying conditions It should be safe to fire after a week drying in the sun and wind. If there's too much moisture in the pelcrete layer it can sometimes swell and crack. A garden moisture meter can be used in reverse of its normal function to check for water content. The oven can be quite happily fired to pizza temperatures once dry, you don't need to be in a rush to add the render/stucco layer before using it.

[angelboy]

So no curing, just wait for a week or so for the shell the dry out. With the sun we’ve had to get the last week it looks pretty dry already and has turned almost white!

I’ve just ordered a moisture meter which should arrive tomorrow so I’ll let you know what it is.

[david s]

Yes the stuff turns white as it dries, but just like a pile of sand that dries on the surface it can remain moist underneath for ages. Another method you can try is a sheet of plastic thrown over the dome during firing will condense water on its underside as the moisture escapes. But having already fired your oven up to 800F you shouldn’t need to be so careful. With northern hemisphere temps so high drying time will be reduced. Not sure what ratio perlcrete you used or how thick it is so ball’s in your court.