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Well it has been a long time between postings but have been working on the dome and figured I would post some updated pics. Had a little problem at the beginning - I used mortar mix instead of masonry cement on my first batch of mortar meaning it had twice as much sand. Had to dig it all out and do it again.
Dome is progressing.....Somewhere around this point I realized I made my dome template the wrong size and was too tight with the radius. I had to straighten it out in the next few chains of brick to make sure I got the dome height correct. Also I read on the forum that you want to under size your entry arch form a little and shim it up to make it easy to remove. I'm glad a paid attention to that as my arch form came out easily.
Decided to go with a sand form and it worked out pretty well. You should definitely see the straightening of the dome giving it a more conical shape. Looks a little odd now but I don't think you will be able to notice anything once everything is covered.
I do have a question for everyone though. There are some pretty sizable gaps between bricks on the inside of the dome. I thought I mixed the mortar loose enough that it would flow into the gaps a little better than it did. Once I dropped the sand form I could see that I wasn't very successful. I started to mix up a new batch of mortar and go inside the oven and try to fill in these gaps but I started to think - is that really necessary? Would I only be doing that for looks? I figure it would be hard to notice once a few fires were burned in it.
If the bricks are tapered correctly, and they can't fall through, I don't see a benefit. I would think it might make the situation worse with bits of mortar popping off into your food.
CJim, our renowned baker and private oven builder, told me last year in no uncertain terms that it is better to fill those voids, which will avoid spalling of the bricks. I assume he means cracking away of the edges that surround the voids in the mortar. I have seen some evidence of that happening in my oven. (I holding off for better weather before I attack mine).
Therefore, I think it is worth a couple of hours of suffering inside the dome in order to get it as perfect as possible.
Yes, I remember that one, too. The point is, that the free-standing edges heat up a lot faster and get a lot hotter than the bulk of the brick - and the temperature difference can cause spalling.
I haven't fixed mine yet either though
Its a lovely dome you've got there Lee - and I like the conical shape, it lends it character. Well worth the extra work to fill those gaps.
How are you going to finish it? I was just thinking, if you went for Igloo style, you could increase the conicalness (conicaliality?) instead of hiding it and you'd end up with a pointy dome... I think that would look pretty cool.
"Building a Brick oven is the most fun anyone can have by themselves." (Terry Pratchett... slightly amended)
Thank for the info. I guess I will be spending some quality time inside my oven today.
Yes Frances it's going to be in igloo with reclaimed old Chicago brick (which you can see my stack in some of the pictures). I'm planning on a center mount chimney so it may end up with a little more of a cone shape when I get done with it.
go inside the oven and try to fill in these gaps but I started to think - is that really necessary? Would I only be doing that for looks?
I wanted to resurrect this because it's an interesting topic. I totally agree that gaps are bad in regard to spalling. But when is good enough, enough? I use a metal wood stove for heat (I do have gas, just hate when it kicks on). I run this thing for 5 months straight in the winter for 4 hours a day (average). After 18 years I replaced the fire brick lining that was not mortared. The bricks were obviously spalled but not just on the edges, it was on the face as well. No mortar joint will keep that from happening. So back to topic - all those fires equates to 10,800 hours of fire. If I use my oven once a week, with a two hour fire, that equates to 103 years! I would think that by that time, I would not know what a pizza is, let alone have the teeth to eat it
What do you all think - I do have some gaps (biggest may be 1/8 inch) - so when is good enough , enough?
If I use my oven once a week, with a two hour fire, that equates to 103 years! I would think that by that time, I would not know what a pizza is, let alone have the teeth to eat it
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