42" Idaho Spud (redeux)

[deejayoh]

Easiest way to avoid the film is to NOT wipe the mortar off with a sponge or wet rag. Wait until it has dried a bit, and cut it off with your trowel. Can even be the next day

[SableSprings]

I agree with Deejayoh and Russell. Your oven looks great inside (and out)...I don't see any need to be worrying about removing that little film of mortar. As Deejayoh noted, it's the wiping after mortaring that's causing the film. Do as he suggested above if you have excess "hanging mortar" instead of wiping it down. From your pictures, the film you've got looks so thin I can't imagine you'll have any flaking onto your pizza. If you can't stand it, do use the vinegar instead of the muriatic acid...it's a lot safer and very effective. You're just are looking for a mild acid to remove the film...why spend the extra money on something that you'll not use for anything else.

You will find that the inside of the dome will go black during most of the curing process and at the start of every firing. When cured, that initial soot/carbon burns off (clears) when the dome gets up to temp 650-700F (if my memory serves me correctly ) and you'll see basically the brick surface as it is now. No worries, you've got a great build going here!

[sharptailhunter]

No matter how I try, I struggle to find enough time for myself😆 I finally placed a few more bricks. It's slowly coming along.

[SableSprings]

No matter how I try, I struggle to find enough time for myself😆 I finally placed a few more bricks. It's slowly coming along.

We've all been there...but look at all you have accomplished! (...and I suspect it's not like you're just sitting around deciding whether or not to have a second adult beverage instead of working on the build ). The nice part is that you are getting close to the point where it doesn't take very many bricks to complete a chain and soon you'll be setting in the keystone!

[UtahBeehiver]

You are at a point on the dome where laying one or two bricks on the next course for the following days work really help the following days work. It will set up overnight and give you an anchor to set bricks against.

[sharptailhunter]

I'm hoping to get some time to work on it tomorrow. Thanks Russ for the tip. I actually left off with an incomplete chain last night but the angle of the pic doesn't really show it that well in the two pics. Thanks again for all of your help and tips you guys, bunch of great people on this forum!

[Flyinglow]

Sharptailhunter, Where at in Idaho are you located at?

[Flyinglow]

BTW, oven looks great, amazed at the speed you are getting it done.

[sharptailhunter]

Hey guys, sorry for being MIA for a while. I had surgery on my arm three weeks ago and haven't been able to really do much until the past few days. Short story is that I'm close to getting the dome closed! The smaller 1/3 size bricks are kinda tricky to cut for some reason. I think the rest will go ok.

I do have a couple questions though:

1. After the dome is closed and I've cleaned up the inside and pointed and tucked the few voids on the inside, how long should I wait before beginning the curing process? It will take me some time to build the vent arch so will that time be long enough for the oven to dry out enough to start the curing fires after the vent arch is complete?

2. I have a pergola that is by my oven. To clear it I'd need about 6' of chimney. I'm thinking of using 8" Duravent. Will that be ok? Too tall? Such a thing as too tall of a chimney?

3. I'm strongly considering putting in some thermocouples. Any input on where would be good places to put em?

4. Finally, is there a significant benefit to putting a render coat of home brew mortar on the outside of the oven after I close the dome (before I start curing fires)?

[david s]

Hey guys, sorry for being MIA for a while. I had surgery on my arm three weeks ago and haven't been able to really do much until the past few days. Short story is that I'm close to getting the dome closed! The smaller 1/3 size bricks are kinda tricky to cut for some reason. I think the rest will go ok.

I do have a couple questions though:

1. After the dome is closed and I've cleaned up the inside and pointed and tucked the few voids on the inside, how long should I wait before beginning the curing process? It will take me some time to build the vent arch so will that time be long enough for the oven to dry out enough to start the curing fires after the vent arch is complete?

2. I have a pergola that is by my oven. To clear it I'd need about 6' of chimney. I'm thinking of using 8" Duravent. Will that be ok? Too tall? Such a thing as too tall of a chimney?

3. I'm strongly considering putting in some thermocouples. Any input on where would be good places to put em?

4. Finally, is there a significant benefit to putting a render coat of home brew mortar on the outside of the oven after I close the dome (before I start curing fires)?

1. If you used home brew which contains Portland cement then it needs to be cured (holding the moisture in to enhance strength) for at least 7 days. If you used a calcium aluminate based mortar then the curing period is only 24 hrs.. It would be best to finish the entry and allow it to cure for a week as well before any drying fires IMO. The drying fires are best done after the insulation has been completed so the moisture is removed more evenly and the temperature difference between the top and bottom, inside and outside, is not so great.
2. The normal requirement is that the flue should be 2' (600 mm) higher than any combustible material.You will need to have stays on the flue pipe if it's tall.
3. Most have one in the floor and a couple in the dome. Thermocouples nearly always fail in time, so arrange it so you can replace them. After firing your oven 20 times you won't really need them, their are other more intuitive ways to tell the temperature that you will discover.
4. None that I can think of. A thin coat of unreinforced mortar will not make the thing any stronger. It's only aesthetics and once covered you'll never see it again anyway. You've already filled any gaps.

[UtahBeehiver]

David pretty much answered how I would too. I have TCs in the brick dome wall one within 1/2" of the inside wall and the other 1/2" from the outside wall to measure when the bricks were saturated with heat. That said, I never use them anymore so IMHO, spend you money on a nice temp gun (the're pretty cheap now a days). You could start curing the oven with some low temp sources like halogen shop lights, then some charcoal. These are easier to control the heat than a live fire. Then you can move up to a fire. On a 42" you will need 8". I did squeak by with 7" Selkirk but that is an odd size. Be sure to get a spark arrestor on chimney cap.

[thevance53@gmail.com]

Did you end up having to support the bricks from the inside, or just use your IT for the rows close to the center? At what chain did you switch to the smaller bricks and what was the size that worked for you? Thanks for your help.

[sharptailhunter]

Hey everyone! Thanks for the replies. I agree about the thermocouple idea and shall put that money towards a good infrared temp gun. Any suggestions of some people have liked? I have a cheap Harbor Freight gun but it doesn't measure high enough for our temps, I don't think.

thevance53, I did use my IT to help support each brick, kind of... I found that when I mix the homebrew before i start cutting bricks and let it sit for about 8-10 minutes while doing the cutting then it makes for a really sticky mortar. Couple that with applying a healthy amount to each wet brick then tapping it down in place with the butt end of my trowel handle makes each brick stick really well. Most of the time I didn't use it to hold each brick in place rather just to check the angle it would offset from the previous chain.

It's hard to say what row I switched to the 1/3 size bricks because they just sort of got skinnier with each chain because of the trial and error of getting the side bevels correct. Another way to tell is if the brick is too wide it will cause the leading edge of the brick, or in other words the face of the brick that faces the inside of the oven, to sit higher off the chain you're setting it on, the previous chain below if you will. That makes for a big triangle shaped gap between bricks. I found that the skinnier bricks made for smaller gaps. Not sure if that makes any sense?

[Gulf]

My HF temp gun measures only to about 700 F. But, that works fine for me. I'm usually only interested in the 250 to 550 F ranges. HF is selling them now that reach 968 F.

[deejayoh]

I have this one - $14 from Amazon.

It measures to 1022F and is smaller and better built than the HF unit. Highly recommend