Curing process after insulation

[pizzahead]

My oven has been cured using the 7 day technique of small to large fires and I now have a couple of questions:

1. do I go through a similar curing process once the vermiculite concrete insulation has been finished?

2. if so should I cure the oven prior to putting the final render/stucco finish on?

Thanks
Jase

[nissanneill]

Re: Curing process after insulation

Why not finish the oven, ie. the dome (done!), the thermal blanket (if one is to be used), then chicken wire if a blanket is used and then the layers of vermiculite (ideally 3 x 1" layers) and then a waterproofing render coat.
I did all this BEFORE i cured as all layers got dried out at once.
If you are to use a thermal blanket, then the vermiculite cement will not get so hot and will dry out but I would have a couple of medium fires before you crank it up into overdrive for pizzas to dry out the final layers.

neill

[pizzahead]

Re: Curing process after insulation

Hi Neill.

What I did was:
1. completed dome and chimney
2. let cure for 7 days and then built up the fires slowly
3. did some cooking in it
4. fixed some cracks in the mortar on the outside of the dome (none on the inside)
4. let these dry out naturally
5. put on the blanket and chicken wire

So what I need to do now is apply the vermiculite cement mix, then render and slowly build up the fires again?

Jase

[nissanneill]

Re: Curing process after insulation

Jase,
I don't believe that you need to go back to square one with your curing.
I lit a few fires from small to the final one in only 4 fires for the whole dome and insulation.
You can follow my build to see.
I would complete the oven build completely, ie insulation and final render. If you need to tile or put on a colour coat, then it won't get even warm if you insulate properly.
I would have a medium, a hotter one say 24 hours later (put a door to plug the opening to retain heat and drive that moisture out and then a final fire.
Keep your eye open for steam or evaporating moisture. If heaps then keep the fire a little retarded than roaring.
Then, 'she'll be right mate!"

Neill

[david s]

Re: Curing process after insulation

The vermicrete layer takes lots of water, about 30 L water / 100 L vermiculite. Given that one litre of water makes 1000 L steam that's a lot. How long would it take you to boil a 30 L drum of water dry ? Don't be too hasty. Let your vermiculite layer dry in the sun for a couple of weeks. For a curing fire, a gas burner sitting in the middle of your oven for 24 hrs works really well. Then you can go to some bigger fires, but not to pizza temp, for a couple of days. I've seen the results of too rapid heating through impatience and it always results in cracking.

[david s]

Re: Curing process after insulation

I took my new oven up to pizza temp for the first time last night. It worked pretty well but the outside is hot to the touch, which means even after slow curing it still contains moisture. No cracks and I will maintain a bit of fire in it today to help it dry more.