Todd's Oven

[asudavew]

Re: Todd's Oven

Before we seriously convince this poor guy to build a mortarless dome, the experts should probably weigh the pros and cons so we can give some good advice! Guys... What do you think??

I say!

If he can do it... build it!

[CajunKnight]

Re: Todd's Oven

mortarless means no stress from hot to cold if properly fitted. if you have the patience for the cuts then do it. you wont be sorry. you are doing great so far.

[Les]

Re: Todd's Oven

I come here for knowledge and support and you turn the newbe into the guinea pig

I think we agree, go for it. Do you guy's think it's possible for the bricks to "walk out" due to the thermal expansion on the bottom courses? If that were the case, it makes a good argument for putting mortar on the outside. I know the upper course bricks won't go anywhere, they are locked.

Les...

[Ken524]

Re: Todd's Oven

I'm strongly in favor of using an inch or two of mortar on the outside of a mortarless dome. I'm a little worried about bumping the bricks with tools during cooking; although gravity will probably keep them securely in place.

I hadn't thought about thermal expansion causing them to shift. One more reason to put a layer of mortar on the outside. The mortar will crack, but no big deal. It will be tightly wrapped with blankets and vermic.

[toddj]

Re: Todd's Oven

You guys set the bar pretty high lol... I feel like a space monkey..

Ok well SO FAR everything fits together tight enough to do it so I will keep going and see what happens.. I will need to mortar my arch and chimney for safety but the dome will go old school gravity... with a liberal coat of heat stop on the outside..

is there any fiber additive i can add to the heat stop mix to make it bind better as a coating... kevlar fiber? any ideas??

[dmun]

Re: Todd's Oven

As you approach the top, the flat, brick to brick mating is lost, even cut sides and top don't compensate for the gaps that form between bricks. If they are tapered in two dimensions, they are unlikely to fall through, but I think they are much more likely to shift.

Me? I'd number the bricks on the backside so if they end up in a heap you can go back and figure out how they go together if there's a problem.

One consideration is that if it were a full dome it would be immensely strong, with the downward forces evenly distributed, but that big hole in the front sets up a lot of stresses in the system. I tried to dry assemble the units for my geodesic dome on the workshop floor, and wasn't able to get up beyond where the sections go flat. Everything wanted to tilt toward the door.

[mannextdoor]

Re: Todd's Oven

I wish I had the talent to try it. Theory says that it should work.

[mfiore]

Re: Todd's Oven

I think you have too much Heat Stop coming!

[toddj]

Re: Todd's Oven

good point dmun! I was just thinking about the delta gap that forms as the radius reduces.. Hmmm... I am numbering everything...

Mike.. its here and 200lbs is a lot smaller than it sounds..

[toddj]

Re: Todd's Oven

well i got kind of agrivated with the floor.. I never leveled it so i took everything down and leveled it on heatstop. then I filled all the cracks with a very wet heatstop mix using a grout tool and followed that up with a damp sponge..

[Les]

Re: Todd's Oven

Todd,

Normally the floor is leveled with fire clay and sometimes sand. I don't know if anyone has mortared the floor to the board - probably no harm.

As you go up in course, the bricks become thinner. The gap angle is no worse or no better then the beginning. It's a curve with a constant radius. The problem I had was holding the thinner brick sturdy enough to get a good cut. If you have the will, I believe it can be done - make us proud!

Les...

[toddj]

Re: Todd's Oven

Thanks Les,

Im not holding them, im a chicken... I made a jig that holds the brick on both sides.

I dusted the vermiculite/cement slab with dry heatstop, pulled a toothed trowel through it then laid the bricks on top and tamped them down. The heatstop started sucking water out of the vermicucrete slab as soon as i put it down.

[Les]

Re: Todd's Oven

then I filled all the cracks with a very wet heatstop mix using a grout tool and followed that up with a damp sponge.

I just went back and read through this post - the above may cause an issue. I think structurally, there is no harm. I do believe that because of the expansion, you will find pieces of heat stop lying on your floor. After a few fires this is probably a moot point. You want your floor flat so the tools don't catch (duh). I used a belt sander to get it true. The general consensus is that the ash will fill all the annoying voids.


Les...

[toddj]

Re: Todd's Oven

Ya, I was wondering how much would pop out.

[dmun]

Re: Todd's Oven

I do believe that because of the expansion, you will find pieces of heat stop lying on your floor.

Not a problem. You sweep the floor before making pizza, after all. This little bit of heat stop may not help, but it isn't likely to be a problem. Most of the fragments will just end up in the ash between the bricks.