39 inch Corner Build

[RandyJ]

I don't know if you have decided on how you are going to do your heat break but what I did was to champher the brick edge that went toward the oven. I believe that I started at 1.25" in and went back 1.25" and left a 1\4" gap that I filled with ceramic rope and then vermicreete behind that and on the inside I used a high temp caulk to seal the inside. It was very easy to do and so far seams to work well.

Randy

[JRPizza]

I like the compactness of Russell's build but can't get enough detail from his pics and his odd brick sizes make it hard for me to translate to my design. I was thinking of starting out like Amac did and transitioning to something like Russell. I also need to study some more hemispherical arch builds.

[JRPizza]

I don't know if you have decided on how you are going to do your heat break but what I did was to champher the brick edge that went toward the oven. I believe that I started at 1.25" in and went back 1.25" and left a 1\4" gap that I filled with ceramic rope and then vermicreete behind that and on the inside I used a high temp caulk to seal the inside. It was very easy to do and so far seams to work well.

Randy

Randy, where did you buy your ceramic rope and high temp caulk?

[JRPizza]

I ended up with a 7 sided hole

[UtahBeehiver]

Almost there, BTW, ceramic rope and HT caulk should be available where you got you CaSi blanket insulation or health board. Now that you are doing the plug, did you ever see Collin's (Oasiscdm) glazed yin and yang plug?

[Gulf]

I ended up with a 7 sided hole

"HeptaForno" .

That looks great! JR.

[JRPizza]

Almost there, BTW, ceramic rope and HT caulk should be available where you got you CaSi blanket insulation or health board. Now that you are doing the plug, did you ever see Collin's (Oasiscdm) glazed yin and yang plug?

I got my insulation from Harbison-Walker. They carry bricks, insulation, and castables, but not rope and calk. I know I can find them locally, just looking for some reasonable pricing. The local kiln supply wanted twice what I paid for the same bricks. I have seen several of Oasiscdm's posts and maybe even his build thread, but don't recall his plug - I'll poke around and have a look.
A question for you all - plugs don't need to be what we called at work "interference", do they, meaning they are slightly bigger than the hole and when driven in place put the area around them in compression? I figured they were just a mortared in slip fit, and even saw cast ones, but wanted to check.

[JRPizza]

"HeptaForno" ......

There have been some famous Sevens (Seven Samuari, Magnificent Seven), but I like HeptaForno

[JRPizza]

Another question - I am weighing two options for my plug. Since I am using fire brick, I need to make the plug out of two pieces. I can do a split down the length of the plug, where the split will be visible from the inside, or a "dual layer" plug, where the joint will be ~2.5 inches from the ID/OD and not visible. The latter is going to be way easier to cut, is there any structural advantage, or am I overthinking again?

[JRPizza]

Ugh, I just remembered if I do a dual layer plug It's going to be 1/2 inch or so too thick and will require shaving or protrusion into/out of the oven, or a bit of shaving/grinding, but I like the look without a seam better. Don't think the food will care one way or the other.

[UtahBeehiver]

JR,

My plug was three pieces, the inner plug was 3" thick with a two piece outer plug. No one will ever see the outer plug config. It is covered by insulation and your final outer coating. Even the inner plug is really only viewed by me when the dome clears and I want to see the "Sun". Your plug will be tapered, I left small gap for the mortar to fill in when I set the plug and just easily tapped in with a rubber mallet but gently. The upper piece I just mortared in the coated with left over home brew.

54F Plugging the Dome 8.11.12.JPG 54I Plugging the Dome 8.11.12.JPG 54J Plugging the Dome 8.11.12.JPG

[JRPizza]

Your oven is a thing of beauty (inside and out), but I am sure you have heard that before. I am going to go for the "horizontal" bond like you and others did. I cut a plug and showed it to the family. They said it "looks good" and since I have so much other work left I am going to concentrate on the bits that will be visible. Probably not worth the work to get the joints equal all the way around. My plug won't be ugly - just not a work of art like yours. I like what you did and Oasiscdm's glaze job, but I am so artistically impaired that I am surprised about how good my build looks to date.
I'll probably pre-bond the top and bottom plugs together, which brings up three questions I have. Should I attempt to clamp the two halves together or just let gravity do the work? Clamping will be difficult as I will be squeezing/shrinking the bond line while I try to apply pressure. Is there a min/max bond thickness I should go for (I'm using homebrew)? Lastly, should I score or groove the interfaces to get more surface area and possibly a better bond, or is that unnecessary?

[UtahBeehiver]

IMHO, the plug is naturally tapered, I mortared the side and tapped in lightly until inner face flush and called it good, then mortared in out plug and let it be. Has not moved a bit. Like you said you got a ton of other things to do before bad weather hits.

[JRPizza]

Wanted to share a tip with any future builders that see this thread. For my final course before the plug I wanted to try to imitate the builds that had all the bricks similar size - I liked the symmetrical look and didn't want to end up with a smallish brick like I did on some of the lower courses. I know it's just aesthetics, but it was the look I wanted. I had picked up a large compass/divider from Harbor Freight that I used to make my inner arch template and will use again for the outer arches. I set the distance at 4.5 (just to start) as that is a brick width and walked the divider around the opening. 4.5 would have given me 6 bricks plus about a 2"er, which was what I didn't want. I decreased the distance incrementally and it looked like about 4 and a quarter would give me all bricks at the same dimension. I used my T-bevel to estimate the bevel angle, as I thought the calculator spread sheet might not work for a 7 brick course (I never checked to see). It's not perfect, but if you want to get close I would highly recommend trying the divider approach. I did end up with a heptagon, but like someone said on the forum, "it's hand made"

[JRPizza]

Well, I went with the dual layer plug. Mortared it together a few days ago and waited for it to cure before I cut it down to 4.5". Got it installed today, pulled out my IT, and inserted the center brick where the IT sat. My insulation was pretty wet under the IT (the wood base had swollen and was a little tough to remove) and you can see how dry/light the replacement brick is relative with the other bricks on the floor. Will have plenty of moisture to drive out once the curing starts. I will probably do a little tuck pointing and brushing off some of the loose sand but it feels good to be relatively done with the dome.