smaller oven

[dingodan]

Re: smaller oven

David- I am aiming for an 18.5 inch interior height and a 12 inch door height. Thoughts?

[david s]

Re: smaller oven

It looks like you are going to end up with a high dome, especially because you have only started to slope in on the second course. This problem is exacerbated for small ovens because the brick units are larger in proportion to the oven size, meaning that wedge on the outside has to be bigger.

But don't worry it, the thing will still work ok.

[Greenman]

Re: smaller oven

A form is a good thing to have when you do this dingodan. It is almost a necessity in my humble opinion. I made one and it worked for me. Good luck if you can wing it but that is beyond my limited skill level.

[dingodan]

Re: smaller oven

So you guys have given me confidence to try the arched doorway. I'll keep you posted.

I'm up to 4 rows. I'm going to try one more without forms, maybe two.

[seamad]

Re: smaller oven

Consider starting the next course at the back of the oven, easy to start a half brick overlap this way and you also get to hide any shitty looking brick adjustments @ the arch, you'll never see them there. I'd avoid using steel angle, brick arches are pretty easy, you may need an angle grinder to adjust bricks though , but they are very cheap and a very versatile tool to have anyway.

[cobblerdave]

Re: smaller oven

G'day
It's easy and strong to built an arched entrance of brick. I have a angle iron one and the disadvantage is the steel will eventually need replacing as it will rust in the hot environment. I've built my outer entry with a brick arch and they are not as hard as I first found. The trick is to build ply form on a couple of wood shims remove the shims and the form drops and can then be withdrawn. You have the added advantage that you keep the form for a template for your oven door.
Regards dave

[dingodan]

Re: smaller oven

I'm realizing that I must now build the door and entryway. The directions say to use a piece of angle iron to hold up the top. Do my bricks just rest on the angle iron? Will the bricks above lock them in place?

[david s]

Re: smaller oven

So, I added row 3 today. In order to avoid grout lines lining up, I cut a brick in half and started laying at the oven opening. By the time I got to the back of the oven, my grout lines were lined up!

Should I have cut another brick or two every so often to keep that from happening?

IMO, yes, but don't pull down what you've already done.

[dingodan]

Re: smaller oven

So, I added row 3 today. In order to avoid grout lines lining up, I cut a brick in half and started laying at the oven opening. By the time I got to the back of the oven, my grout lines were lined up!

Should I have cut another brick or two every so often to keep that from happening?

BTW, I'm using half fire brick and trying to cut as little as possible since I have to score and break them. I rented a saw to cut all the fulls into halves, but I'm on a tight budget so I can't custom cut every brick like some of the gurus on this forum.

I'm actually surprised how much confidence I have gained doing these first 3 rows. I'm sure that will be tested as I get closer to the top -- that looks scary up there!

Thanks for all of your suggestions and advice.

[dingodan]

Re: smaller oven

This shows how my stand is built into our back hill.

[vertigopilot]

Re: smaller oven

I put on the second row. As you can see, the walls of the dome sit slightly over the edge of the hearth. When I switched from barrel to dome, my base was slightly too skinny, but I didn't want my oven to be too small. I know I'll lose some heat, but I'm hoping it is not too much.

The hearth is sitting on almost 4" of insulating perlite/concrete and the oven wall bricks are mostly on the hearth, so, we will see.

Dingodan:
I'm not an expert, having only built a handful of ovens so far, but I've been at the same juncture where you are now with your build: wondering whether the reduced insulation envelope will much affect overall efficiency, or whether it would be worth the effort to do some re-working at this point.

From my past experience comparing the results of build decisions, I would say that only 4" of perlcrete under your floor, reduced insulation space around the perimeter, and the thermal bridging that will come from the decorative bricks around your oven floor, will all add up to considerably faster rates of heat loss than you would guess.

If wood is plentiful and cheap - and you enjoy stoking the fire more frequently - then it won't matter much. But if you look forward to extended baking and roasting sessions post-firing, then you'll want to make the necessary design modifications now while it's still easy. You might consider removing the floor perimeter bricks, adding a another row of block or brick wall around the perimeter of the base to provide support for an enlarged wall area, and extend the perlcrete out wider so that your dome insulation will connect with the floor insulation to fully envelope the oven without unnecessary thermal breaks.

It all depends on what your goals are. The most important thing is acting on your ideas. There is undeniable magic in Action!

[dingodan]

Re: smaller oven

Good eye on the height. The oven is built into our back slope so it looks low, but it is actually elbow height.

Thanks for your opinion on the heat loss. I was hoping it'd be like you said, but it's nice to hear an expert agree.

[david s]

Re: smaller oven

Hard to tell from your photos, but it looks like your floor height will be pretty low. The standard is around elbow height. You might have to do some stooping, but you get used to whatever height you've built. Looking good so far. You might lose a bit of heat conducting from the floor to the outer perimeter bricks, but not too much to worry about. Because a smaller oven is so much more economical with fuel (consumption is proportional to oven volume), it's no trouble to use a little more fuel or refire.

[dingodan]

Re: smaller oven

I put on the second row. As you can see, the walls of the dome sit slightly over the edge of the hearth. When I switched from barrel to dome, my base was slightly too skinny, but I didn't want my oven to be too small. I know I'll lose some heat, but I'm hoping it is not too much.

The hearth is sitting on almost 4" of insulating perlite/concrete and the oven wall bricks are mostly on the hearth, so, we will see.

[dingodan]

Re: smaller oven

Great info and advice everyone. I'll post pics soon as I hope to lay row 2 tomorrow.