K79 Oven Build

[SCChris]

Re: K79 Oven Build

Not knowing what either looks like, what are the functional differences? What are the aesthetic differences?

After knowing these, make a decision and live by it..

No guts, no glory!

Chris

[stonecutter]

Re: K79 Oven Build

Can you please explain the re-temper procedure?

I am not speaking for Tscar...just as a Mason. Re-tempering any mortar mix involves adding only enough water for a workable consistency within the accepted time. For HeatStop, after the initial 10-15minutes, re-stir everything in your container before adding the water. Then only add enough to bring it close to were it was when you started. Don't re-temper more than once.

[K79]

Re: K79 Oven Build

Great thanks for the info guys.

So how do these cuts and brick sizes look before I mortar them tomorrow in the a.m.? The IT is not in the right place Just my wall bricks are going in, in this photo. The floor bricks are just because I wanted to put some down.

[stonecutter]

Re: K79 Oven Build

They look very precise...hurry up and start mudding them in already.

[SCChris]

Re: K79 Oven Build

79 the bricks look like you want to dry stack the oven and I fear you're going to find that mortar isn't as thin in the joints as you anticipate. Plan for trimming a brick or two to fit your rings.. Are you planning a "Les" style" oven where you only mortar the back of the bricks?


Chris

[K79]

Re: K79 Oven Build

79 the bricks look like you want to dry stack the oven and I fear you're going to find that mortar isn't as thin in the joints as you anticipate. Plan for trimming a brick or two to fit your rings.. Are you planning a "Les" style" oven where you only mortar the back of the bricks?


Chris

I started this a month or so ago when there was still ice on the ground. I wanted to get them cut as precise as I could and do plan on trimming some as I go / as needed. Some joints on the back side are around 3/8". Also I'm not familiar with Les' oven so not sure if that's a compliment or what

[kbartman]

Re: K79 Oven Build

Kbartman, you really do not want to use that refractory cement on your build. It is made for MAXIMUM joint width of 1/4". It is also water soluble, so wetting it is not doing any good. It is a heat-set mortar.

For Heatstop, mix no more than you will use in 10-15 minutes. Slowly add water until is a tad wetter than peanut butter. Once it begins to set, you can re-temper it once (remix it), but after that throw away any left and mix a new batch. It does not need to be kept moist to cure.

thanks kbartman. I'm using Heat Stop for my high heat mortar. No instructions on the bag. I'm going to try and give them a call. What is the normal procedure? You need to spray the mortar until it cures? Roughly how long is that? I'm planning to cover my dome while not working on it with a tarp?

Can you please explain the re-temper procedure? Basically at around the 10-15 minute mark if it starts to change consistency I can mix it and it'll be good for about another 10 minutes?

My thoughts are only to slow the air curing process. I believed this would make a better cure.

K 79 your oven is looking good.

[UtahBeehiver]

Re: K79 Oven Build

Believe me it is a compliment to be compared to Les, his is almost a mortarless build. You will most likely encounter what I call for a lack of a better term, mortar creep. You will most likely have to make adjustments. Do them near the front end not the back half. You will never see them that way after the dome is complete unless you stick your head inside. Nice looking start......

[Tscarborough]

Re: K79 Oven Build

Yes, when pre-cutting, always leave the last 2 brick until the rest of the course are in as you will be cutting them again anyway.

If you insist on using that mortar, you will need to add some fine to medium grit sand to keep it from shrinking in joints larger than 1/4". What you have laid is fine, but as you go up the dome, you will begin to get 3/8" to 1/2" joints on the face and even larger ones on the back side.

I used that type on my barrel vault, but I was able to keep the joints thin on the face and fill in the back with a different mortar. Again, I don't recommend it's use for a Pompeii oven.

[SCChris]

Re: K79 Oven Build

79, you're going to find that as you go higher in the courses you're going to start to see "V"s from the prior course. I mention this now because you need to understand that unless you cut and place and mix a coffee cup of mortar at a time you are going to have to accept the mortar joints are not as tight as you might have dreamed that you wanted or needed.

From time to time it's important to remember.

1- Cracks are to be expected.
2 - Insight comes with experience and most of us start with no personal experience.
3 - A dome built with half bricks and a dump truck of mortar still cooks incredible pizza.
4 - Insulation is a minor part of the cost of the build, even the expensive insulation.
5 - A dry dome is a happy dome
6 - Someone around here has done what you're doing
7 - Your back will get tired.
8 - Opinions are like ..., everyone has one.

:-)

Chris

[K79]

Re: K79 Oven Build

Yes, when pre-cutting, always leave the last 2 brick until the rest of the course are in as you will be cutting them again anyway.

If you insist on using that mortar, you will need to add some fine to medium grit sand to keep it from shrinking in joints larger than 1/4". What you have laid is fine, but as you go up the dome, you will begin to get 3/8" to 1/2" joints on the face and even larger ones on the back side.

I used that type on my barrel vault, but I was able to keep the joints thin on the face and fill in the back with a different mortar. Again, I don't recommend it's use for a Pompeii oven.

Thanks everyone for the help. I'm using Heat Stop. You're not referring to that are you?

[Tscarborough]

Re: K79 Oven Build

No, not Heatstop, it is fine for thin or wide joints.

[K79]

Re: K79 Oven Build

Ok guys I'm in the process of laying my ceramic fiber board. There are some gaps between my fiber board and my hearth slab. How do I level these so my board doesn't crack when the brick is laid. They are about 1/4" at the edge. Can I lay a bed of fireclay between my hearth slab and my insulation board? At a stand still !!!!

[Tscarborough]

Re: K79 Oven Build

Yes you can use the fireclay.

[K79]

Re: K79 Oven Build

Ok guys I only have enough fireclay to go around the perimeter of my ceramic fiber board. Is it ok to level it going around ther perimeter and not smear it across the entire hearth slab. There will some voids under my insulation board. Also I noticed some fine cracks in my board are these oK?