To keep the oven hot

[Les]

Re: To keep the oven hot

I'm really not sure how much the heat break offers. I had a post of the temps on the inside and outside of my door and I recall it was a couple hundred degrees delta (can't find the link). I tested this last night, obviously if this were steel my finger would have been toast. Clearly a heat break won't hurt but is it worth the labor?

https://www.youtube.com/edit?video_i...m-upload_owner

[DBinnema]

Re: To keep the oven hot

I feel that having decided to add the extra layer of insulation underneath, I can skip the thermal break (unless it is very simple to do) and maybe put some extra effort into having a good door - something that looks to be in my very distant future at this point.

There seem to be mixed opinions about the benefits of a thermal break, but it also seems that regardless of its presence a well-insulated oven can stay hot enough to bake some break on the second day, and even cook something in it on the third. Good enough for me!

[deejayoh]

Re: To keep the oven hot

I checked out McGill's Warehouse, and the prices were indeed good , but the shipping was over $300,

Interesting. I just loaded up a cart there with 4 rolls of 1" blanket and 2 pieces of 2" CF Board and the shipping was $122. That seems pretty good to me, doesn't even come close to eating up the savings vs. other suppliers.

Maybe it's because you're in Canada? (and a little off the beaten path)

I see they now also carry diamond saw blades and concrete polishing supplies for good prices. Weird store, but good deals

[DBinnema]

Re: To keep the oven hot

Yes - it is my location that is to blame.
This oven is costing me roughly three times what it would cost me if I lived somewhere a little more... "beaten". It cost me $400 just to get firebricks sent up here on a barge. I might have thought twice about taking this on had I realized how expensive it would be - but too late now. I suppose there has be SOME downsides to living in paradise.

[Gulf]

Re: To keep the oven hot

"It only takes some spacing between the floor bricks in your oven and the floor bricks in your entry so they do not touch to make a heat break. About 1/8th to 1/4 inch will do. You can place ceramic fiber tape in that divide or just let it fill up with ash " (Gulf)

- Only a space between the floor bricks? Why not the arch?
It would be a lot simpler to just have spacing between the floor bricks...

Yes, on the floor brick, no on the arch brick. Because, the smoke and heat would escape in the space between the arches. Someone else on the forum can attest to that. I am not sure just how much of a problem that would be, but it would at the very least, be un and would probably effect the draw to some point.

[DBinnema]

Re: To keep the oven hot

Awesome - I can easily (and now plan to) do that.
I'll leave a 1/4" gap in the floor just in front of where the door will sit. Thinking of switching from the harringbone pattern to just rows of bricks for the entry way. Perhaps I'll leave another 1/4 gap at the very front on the entry way.
So, how hot does the entryway / vent get? (cool enough to allow for the use of regular bricks?)

[deejayoh]

Re: To keep the oven hot

The entryway and vent get quite hot near the oven. Especially where the gasses/smoke are coming out of the dome. The reasons you use firebrick in the oven are a) heat retention and b) to prevent bricks spalling (firebrick are more durable in heat/cool cycles than clay brick). The first reason isn't really relevant in the entry arch. It's the builders choice if they want to make the investment in firebrick to reduce the chance of spalling.

My $0.02 is that the entryway takes only a couple dozen bricks. The added cost is so minimal I'd use firebrick. But that is just me.

You don't need a gap between the entryway and the landing. it will just collect ash and dirt, while delivering no benefits in terms of heat retention or cooling.

[eprante]

Re: To keep the oven hot

If the cost of shipping is that high I would go old school and insulate the bottom with Vermicrete. I did that on my oven and (5" thickness) and I get similar heat retention to what Les posted. I think a well insulated door is key. My door is insulated with 2" of the FB blanket and seals very well
Eric