Calculating How Much Castable

[iijakii]

Hi,


Im going to start on a build soon, probably do 30" interior diameter. Ill be driving an hour or two to pickup the refractory, was just wondering if anyone has an idea on how to calculate how much material is needed? Been struggling trying to figure it out. If you could post your oven size and how many pounds of refractory you used that'd be greatly appreciated!

[iijakii]

Alright, think I figured it out. Derp, easy once I thought about it.

Area of the outside dome minus area of the interior dome.

[david s]

Alright, think I figured it out. Derp, easy once I thought about it.

Area of the outside dome minus area of the interior dome.

No, not area, volume. The formula is 4/3 Pi x r3
Don’t forget to halve it because it’s a hemisphere.The extra volume around the oven mouth is approx equal to the mouth itself, so calculate as the full volume of the hemisphere. You will also need extra for the flue gallery. Best cast as another piece after the dome has set.
Make sure you get dense castable not insulating castable.

[iijakii]

No, not area, volume. The formula is 4/3 Pi x r3
Don’t forget to halve it because it’s a hemisphere.The extra volume around the oven mouth is approx equal to the mouth itself, so calculate as the full volume of the hemisphere. You will also need extra for the flue gallery. Best cast as another piece after the dome has set.
Make sure you get dense castable not insulating castable.

Alright, thank you.

So Ive been reading you say 2" thick cast is plenty, right? I was originally planning on going thicker but Ive been reading a lot of the threads on here with you mentioning that. Ill gladly go to 2" and save, heh.

Im not quite settled on an interior dome size. Keep going back and forth. It'd mainly be for just a few pizzas here and there, but would like it large enough to try using it as a smoker for some meats as well. And to fit a cast iron dutch oven for baking breads. Thinking 32", although that's probably overkill. So if I go 32" the dome would be 2.10cuft castable -- let's call it 6x 50lb bags. Not sure on how many for the flue gallery. There's a guy near me selling some propriety refractory for $25lb, think I'll be safe grabbing ten bags.