excess cement on outside of dome.

[gtofani]

Should I or shouldn't I be spreading the extra cement over the outside of the dome? Am I supposed to spread a thin coat over the whole exterior when it is completed anyway? The dome is not going to be seen when completed.

[Neil2]

Re: excess cement on outside of dome.

Don't put cement on. Generally a 1/2 inch or so of mortar (or even concrete) is spread on.

[gtofani]

Re: excess cement on outside of dome.

Do you use the same mortar as I am using for laying up the dome.
The homemade fireclay mix?
Then after the dome is done, and I wrap it in the blanket of insulation, what mix do I use over top of the insulation?

[Ken524]

Re: excess cement on outside of dome.

Gino,

You don't need to add any mortar to the outside of your dome. Pompeii ovens, when built with half bricks according to the plans have plenty of thermal mass. They have much more mass than any of the kits. Some people add a thin layer in an attempt to strengthen the structure. I don't think it's necessary. Cracks will happen whether or not you add the mortar. The extra layer will certainly not make the difference of whether your dome will remain standing or collapse.

[RTflorida]

Re: excess cement on outside of dome.

I used about 1/2" of the HeatStop 50 that I had used for the build, kind of costly, but I had a 1 1/2 bags left over. I figured it wouldn't hurt a thing and it gave me a smooth uniform surface (which I really didn't need) before the next step of blanket and chicken wire. For me, it just made the oven more complete looking for that week, as I didn't proceed until the following weekend.
Totally unnecessary, but alot of us have done it.

RT

[Mike D]

Re: excess cement on outside of dome.

I put extra mortar on the outside of the dome mostly because it helped keep the bricks in place better (when I was mortaring them on). When they get vertical it really helped them stick. It wasn't a lot but just enough to give it an extra connection.

Mike

[chidding]

Re: excess cement on outside of dome.

I also put the extra mortar because i found it helped keep bricks in place when building.. same as Mike D..

Plus it looked nicer during construction.