42" Idaho Spud (redeux)

[thevance53@gmail.com]

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?

Yep, perfect sense. I have actually been measuring to the wrong side of the brick when cutting, so my bricks have been a little oversized for a while. Still not too bad on the grout joints until the 10th chain. Boom, it was obvious i had to cut the bricks down. The steeper you go, seems like it is a little harder to keep them level. I will try and use my IT as long as I can, but I may have to remodel it again. Thanks for the response.

[JRPizza]

Something I figured out a few rows into my build is the ideal dimension for a beveled brick is for the bottom width to be same as the top width of the bricks in the row below. Ideal in the sense that you will never have a vertical joint align with the joint below, and all bricks in the row can be the same size except for where they tie in to the arch. After I started doing this I was able to stop using "slivers" of brick to keep the joints from aligning. I think some of the spread sheets have this information in them in tabular form, but it didn't register to me looking at the numbers. When you get to where you are using 1/3 bricks, the row above can go to having the bottoms twice the width of the top of the rows below, which gives you a more manageable brick size and still avoids having joints align. If you look at pictures of most of the "quality" built domes you will see this transition to wider bricks near the top.

[sharptailhunter]

Well, I finally closed the dome, yay! It did seem like I was never gonna get to that point. It didn't turn out as well as I was hoping for but I think it should still function ok.... I hope!

Tonight. Cleaned off the excess mortar and residue from inside the oven. What an unpleasant experience, so glad to have that done! It's good to see the floor bricks again. I made a wooden vent arch support to assist me in building the vent arch. I'm planning on doing that this weekend. Fingers crossed my anchor plate shows up tomorrow.

I'm not planning on doing a floor heat break but I have some fire rope and high temp caulk that I'm planning to use as a heat break between the oven and the vent arch. I'll a,so use it to seal the anchor plate to the vent arch.

[UtahBeehiver]

Nice work and you have done the right of passage by climbing in the oven.

[staestc]

Oven looks fantastic! Well done!

[sharptailhunter]

I got the vent arch built and the anchor plate attached. For a heat break I cut all but about 1/2" of material off the part of the brick that butted up to the oven entry arch. That way when the vent arch was complete it left a channel or void between the oven and the vent arch on the outside but on the inside of the vent arch it's brick in brick. Not sure if that makes sense or not but you can see in the pics the void that I then sealed on the outside with some fire rope and super high temp fireplace caulk shtuff. I also used that same rope material and goopy stuff to seal the duravent anchor plate. Forgot to take a pic of the hole from the vent arch to the chimney, woops.

So, the last batch of mortar on the oven proper has been ambient air curing for 8 days. The vent arch has mortar that is 3 days old. Am I ok to cover it with ,y ceramic blanket tomorrow? I'm presuming I wanna insulate the vent arch as well, yes/no?

After the blanket is applied and secured, I plan to start building a metal stud and durarock enclosure around it. The roof part has me a bit confused. I wanna use durarock because it's not combustible, right? Does that hold true for the roofing material too? If so, how does one attach asphalt shingles to the durarock? Also, any suggestions on how to "screw" the metal studs to the hearth slab? I guess Home Depot would have some concrete screws that'd work??

Finally, I should wait a full 7 days from the last time any mortar was applied to it before I begin the curing process, correct?

[Caliea]

I'm a newbie when it comes to ovens, so I don't have any tidbits for you on that front, but you should be able to get TapCon screws at Home Depot. They are made to go into concrete and should work well to secure your metal studs to the heath slab.

Oven looks great! Congrats on finishing the dome!

[sharptailhunter]

I suited up and got the ceramic blanket insulation on the outside of the oven. Man is that stuff nasty! Was able to get about 4" thick of insulation around the dome and about 2" over the vent arch. I then got the steel stud walls framed up and three of the trusses for the roof on. We had three solid days of rain that stopped me from working on it. But, during those days I had a 500w halogen light on inside the oven with tarps over it. I think that really helped to cure the mortar that had already been cured for five days prior to those three. So, I began my first oven curing fires this weekend. I started with charcoal briquettes. Those were nice at keeping the oven right at 300 degrees on Friday. Saturday I took it up to 350-400 using small sticks and logs. The chimney drafts really well. The only time smoke would come out of the vent arch was with wind gusts. Yesterday I got up it up to 450-500 for the whole day. Sadly, I'm back at work today for a long day. I have a make shift door over the opening hoping to keep it fairly warm. Tonight I'll try to cure it some more. The plans say I have to start all over back to 350 degreees. Does that sound right?

[UtahBeehiver]

Yep, the CF blanket is nasty but your are suited up right. Since you are doing an enclosure the CF fit does not have to be a perfect sphere, just secured. Don't speed the cure, this is where I see a lot of builder get impatient and fire too high and too quickly. You should be able to do some lower temp cooking during the cure process.

[sharptailhunter]

I just found the sticky of curing your oven in the Firing your oven forum. The process there is different from the one described in the downloaded plans. In the plans it says to try to maintain the heat by using a door. In the forum sticky it says to just get it up to temp and then let it cool back down. Obviously I haven't been doing that but I will start with the heat up and cool down method. So far I haven't seen any cracks so I'm keeping my fingers crossed that I didn't do anything wrong?! As such, I'll leave it be for today and let it cool down. I need to clean out the ashes from inside anyway.

After the stud enclosure is built I'm going to skin it with Durock cement board. Then I plan to pour loose perlite over the ceramic blanket, mainly to help hold it in place snug against the dome. Does that sound like a good idea?

[UtahBeehiver]

I think 4" of CF is plenty good but if you want to pour dry perlite that's up to you. Some builders block off the corners of the enclosure with scrap wall board or handi board to cut down of the amount of perlite. Everyone gets cracks somewhere, it they say they don't then the are a politician or a used car salesman or both............

[sharptailhunter]

I've been tackling the steel stud and Durock enclosure all the while curing the oven with fires. Today the dome turned clear (white) from the center to just about 2-3 rows up from the floor. It was measuring on average 720 degrees. Is that about the right temp for the dome to clear? So far no cracks! The curing instructions are a bit confusing between those outlined in the downloadable plans and those in the sticky. So, each day I've been building a litttle bigger fire and slowly getting it up to the temp I had it the day prior then I bump up the heat a little more, usually to the next n x100 degree and try to keep it at that temp for at least four hours. So far things have gone really well. The floor and first couple courses are usually pretty close to the dome temps. A fun thing to look at is how well the heat break is working between my oven arch and the vent arch. Usually it's at least 50% cooler than the oven. No leaks through the gap I filled with the fire rope and caulk either so that's good. The CF blanket is amazing stuff. 725+ degrees inside the oven and the blanket is 81 degrees outside... prolly because the ambient air temp was also 81 degrees today :-) The chimney draws well too. So far no soot on the front of the vent arch.

Now I need to read up and study how to stucco over Durock. Does anyone have any links or good tips they wanna share about that?

Thanks, Alex

[david s]

Be careful here. The ring of persistent black soot around the bottom means there's still moisture there and the bottom of the oven will be way cooler than the top which means uneven expansion. You will be wanting to increase the intensity of the fire, but that is precisely the wrong thing to do. Try to spread the coals out to the perimeter to help dry that area.

[Caliea]

^ that looks like excellent advice. I'm filing that away for when I start my curing process. Thanks, David.

[gastagg]

Alex, I found the YouTube Quikrete video helpful for stucco. I have a stucco igloo enclosure and used the quikrete stucco product for my first try. Ended up using a BASF product when I had to apply stucco the next year for a final finish coat. If you're going to color your stucco, I ended up using a full bag (2lb) of professional mortar colorant per 80lb of white stucco. Got the color I wanted by NOT following the instructions. Oven looks great! Way to keep at it. I've learned that the project is actually something you do over time. I'm adding a counter next summer...year 3. Used it tonight to cook a couple of Giordanno's frozen deep dish pizzas. We loved them.