Teardrop

[Mike D]

This is a post from my build "Round Shape". I wanted to separate it to give people in the planing/design stages a heads up, as well as others to jump in and add anything that makes more sense.

-I think I might have a design flaw. I can see the teardrop over the arch coming, and I think it is because my arch is too far forward. If the arch was farther inside the dome the round shape would rest on the arch, but with the arch too far forward the dome falls inside the top of the arch.

-This might be why people get the teardrop. I don't remember reading about this in the plans or on any other threads.

-Here is how I figured out my design flaw. When I put my wooden guide under the arch, I thought it wouldn't line up because the arch would (should) obstruct it. It doesn't even touch when it is lined up with the circle on the floor. If the arch was pushed in more, it might be fine (without other human mistakes).

-If you look at the 4th picture you can see how the first row lines up with the arch. I think if the arch is pushed in more so the outside edge of the arch brick lines up or hits the first row the arch will fit inside the dome. At this point my arch would technically be on the outside of the dome. This is because the inside edge of the arch brick is touching the cooking floor. As in pushing the whole Arch inside the cooking floor puts the arch inside the dome.

-I think I will have to push a teardrop to connect the dome to the arch and then correct the shape as others have done.

Mike D

[Lburou]

Best insurance against a teardrop...

Karanga Dude shows the best insurance against a teardrop I've seen.

For future readers: Post number 26 of this thread shows how he cut the back side of the arch bricks for a smooth transition from the dome to the arch....Pure genius and I don't see a down side!

[Les]

Re: Best insurance against a teardrop...

shows how he cut the back side of the arch bricks for a smooth transition from the dome to the arch

I don't see how that will help in this situation - the bricks are going to fall short of the arch.

Mike, you are close but it looks like its 2-3 inches short. It still might work. You will have the ring butting up against the arch instead of hanging on it. As long as it doesn't push out the front (and you will have a lot of brick in front of the arch for support), I can see it working as is. It's hard to really tell from pictures, but if the half brick doesn't reach, a full one will for sure.

[Lburou]

Re: Best insurance against a teardrop...

I don't see how that will help in this situation - the bricks are going to fall short of the arch.

Mike, you are close but it looks like its 2-3 inches short. It still might work. You will have the ring butting up against the arch instead of hanging on it. As long as it doesn't push out the front (and you will have a lot of brick in front of the arch for support), I can see it working as is. It's hard to really tell from pictures, but if the half brick doesn't reach, a full one will for sure.

My bad. I'm at a disadvantage not having seen pictures of his 'current' situation until now. :humble:

[Mike D]

Re: Teardrop

Thanks guys-
-I think I will be able to connect everything together, I was mostly starting this thread to help future builders think about their layout before they got too far (like me) along in their build to prevent this situation.

- Yes Les, I too was thinking about needing to use a longer brick over the arch to tie it all in. I think it would be stronger hanging on top of the arch that pushing up against it.

Mike

[brickie in oz]

Re: Teardrop

There is a relationship between the arch height and dome height that must be kept, if its changed the teardrop will form.

If you make the entry arch too low, or move it forwards too much you will get tears.
Same goes for the oven dome.

If you make the entry arch higher you will get a D shaped dome.

Take a line from the top of the entry arch to your form or indispensable tool to see if it will happen or not.
The line needs to be 100mm (4 1/2") down from the top of the arch as thats where the bricks in the dome will end up at.

Ive tried to show a line in the pic, but I cant see the top of the dome profile.

The dome shouldnt be a complete dome at the front on the floor when you set it out, it needs to be truncated with a flat face.

Picture 7.8 on the plans shows the forms clearly cut short to allow for this.

[SableSprings]

Re: Teardrop

I built a 39" Pompeii style dome (actually with more of a tear-drop/beaver tail hearth) using standard firebricks and perlite/cement insulation. I thought the tear-drop shape that formed naturally from my layout was "normal". I have to admit the final bricks over the oven opening were odd shapes to cut and fit, but they seemed to make for a very solid structure. The sweep of the wall/hearth makes pulling ash into the ash slot very easy. The one thing I love about this "surface flow" is how easily I can see & access my entire hearth surface during baking. I also wanted the exterior look of brick instead of the "gray" perlcrete, so I cut bricks length-wise to reduce weight and created a barrel vault false exterior over my "roundish" oven. Check either my Dragonfly Den photo link at the bottom of www.sablesprings.com or in Forno Bravo albums (The Dragonfly Den, posted by SableSprings) to see the result. Since my brick facade rests on the concrete platform outside the actual oven footprint-not on my underlying perlcrete hearth insulation-I don't have any worries with the additional weight.