How hot does entrance hearth get

[waynebergman]

How hot does entrance hearth get? Wondering about this because if it does get hot maybee we don't want it to get hot as it might be an area that if it had a insulation break between hearth floor and cooking floor then this entrance hearth wouldn't waste heat up time and it might make things more effecent. Why soak this area if we dont need the heat there? I have not seen one of these ovens in action although I am building one so still not real sure what gets hot and what doesn't. I understand that the vent above we want to get hot but maybee not the floor area. I myself have used the same mortar and brick treatment for this area as the rest of my dome construction so my question is only of the curious sort. Picture above is of round 8 completed today. ...... wayne

[RTflorida]

Re: How hot does entrance hearth get

Wayne, I'm have no idea if we want it to or need it to, but mine does heat up quite a bit. The hearth area between the flue and and where the dome begins gets in excess of 400 degrees by the time the oven has burned white - ready for pizza.
I've read that others have used this area to preheat logs (especially if the wood may be a bit green). All of the wood I've used has been pretty well seasoned, but not knowing any better on the first couple of big fires, I tried the preheat and those logs actually started to smolder within just a couple of minutes. you would actually have no problem cooking something at a slighty lower temp in this area.

[Frances]

Re: How hot does entrance hearth get

I think I read a thread somewhere which said that yes, you could insutate between the dome and the arch, and yes, you do loose heat there, but that it would be so complicated and the advantages (added heat retention) would be so small, that its really not worth the effort.

[christo]

Re: How hot does entrance hearth get

That's the area we use to bake cookies after the pizzas are done....

Christo

[Ken524]

Re: How hot does entrance hearth get

That's the area we use to bake cookies after the pizzas are done....

Ahh... So we definitely need that area hot!

[wlively]

Re: How hot does entrance hearth get

I pondered that question when I was building mine. It is hard to have good seperation and still look good because you would have a large gap to get a really effective temp barrier.

I decided to go with a subtle appraoch. At the first continuous horizontal seam in the entry, just outside the oven opening I cut the side of the brick at a 45 degree angle. So from the top the brick looks full size, but from the side you can see the lower long corner cut. I then painted some aluminum ceramic paint ITC-100 HT on the side of the cut brick and the side of the entry seam to reflect IR and finally placed the bricks with Perlite in the void created by cutting the brick. If you look at pictures of my entry you would never know anything special was done.

I would not buy any ITC-100 again, it would not be worth it. I was planning to use over the entire dome, but it turned out that would not be a good idea. My treatment seems to be effective as with my IR gun I see almost a 200 deg difference across the seem.

[Les]

Re: How hot does entrance hearth get

Wlively,

Do you have a link to those pic's? They are not in the photo gallery.

Thanks,

Les...

[Ken524]

Re: How hot does entrance hearth get

At the first continuous horizontal seam in the entry, just outside the oven opening I cut the side of the brick at a 45 degree angle. So from the top the brick looks full size, but from the side you can see the lower long corner cut. ... placed the bricks with Perlite in the void created by cutting the brick. If you look at pictures of my entry you would never know anything special was done.

I have a plan that is nearly identical to Wade's (great minds think alike ). At the start of the vent landing, I am planning to cut a rabbet in the row of bricks on the "cold" side and fill the void with scrap insulation board (CalSil, SuperIsol, Kaowool, etc). The top of the seam will be mortared (as is Wade's) to hide the dirty little secret. A profile view is posted below.

The more I think about it, Wade's 45deg angle cut may make the brick more resistant to breaking or cracking. I may steal your idea, Wade.

[Ken524]

Re: How hot does entrance hearth get

Here's a minor improvement, and probably a bit closer to Wade's design:

[Les]

Re: How hot does entrance hearth get

Ken - it looks like you already have some of the entry bricks laid, is that not the case? Anyway, this topic came a little late for me. I'm commited.

Les...

[Ken524]

Re: How hot does entrance hearth get

Les,

My entry bricks are not mortared yet, just sitting there. They are awaiting some trimming to allow for mortar joints.

[asudavew]

Re: How hot does entrance hearth get

Ya'll going crazy on me?

Solid brick for me!

I've gone nuts enough already!!!

[wlively]

Re: How hot does entrance hearth get

Les

Sorry, I did not take any pictures of the cut or process. I was referring to the pictures of the landing were you can't see any difference. Ken has it right on with his drawing though. I took the 45 as far as I dared without damaging the upper or "show" corner.

Great drawing Ken and there is not such thing as "stealing" here, we are all simply "appropriating". Oh, and you are right about the mental thing!

[Les]

Re: How hot does entrance hearth get

Do you feel that there is that much heat thermally conducted from brick to brick to be an issue? My entire entry way is sitting on 4 inches of insulation board.

Les...

[Ken524]

Re: How hot does entrance hearth get

Les,

I sort of think this whole discussion may be more about splitting hairs then really helping efficiency . I'm sure there is going to be brick to brick conduction of heat, but I'll bet it is pretty minimal.