Portland/Vermiculite question

[skemcis]

Hi, Popped in the final keystone tonightconfused. I'm curious as to whether I should apply the cement/vermiculite now, or wait until the fire clay has cured somewhat, or until after I fire cure the oven. Hopefully I can entice a neighbor to take some pics so I can post them.

[dmun]

Re: Portland/Vermiculite question

You need to keep your dome covered and damp for at least a week before you begin heat drying. Whether to cure before or after the insulation is in is a matter of some dispute. With the vermiculite concrete, which retains a LOT of water, you may want to dry it out afterwords.

[skemcis]

Re: Portland/Vermiculite question

Hmmmmm... ok, I understand about keeping the dome damp, have been since the soldier course. Because the oven will be 'housed' I was wondering if a portland/vermiculite mix is a good way to go. I have a full 12" of free base for insulation and was considering just pouring loose vermiculite for the full void. The framing for the 'house' is full 2*8 and I was going to insulate that with R40 fibreglass. The roof section will allow a full 24" of insulation above the dome. The reason for all this is the -30 winter weather we get, and the fact that the oven will be used 5 days a week. I'm just being mindfull of the wood use. Any comments gratefully appreciated.
Ian

[dmun]

Re: Portland/Vermiculite question

If your oven is in a leak-proof enclosure, you can just pour in the vermiculite loose. You probably want to put angled sheets of some non-combustible material in the corners to reduce the volume of material you use.

[skemcis]

Re: Portland/Vermiculite question

Excellent, thank you!

Ian