Cinderblock oven

[drnez]

Hello everyone. I was curious if anyone has build a cinderblock oven. My idea is to build cinder blocks around the sides and fill them with insulation. I was then going to use hardi concrete board inside and out to dissipate the heat. I havent figured out what I am going to use for a door yet. how does this sound? Am I forgetting anything? I will be using 4 electric heating elements, most likely only 110v. The dimensions will be somewhere around 4x4x5 (LxWxH). Anyone have any cleaver ideas for a door? could I use a fridge door with isolation, concrete board, and I high temp seal?

[defed]

i'm not crazy about the idea. seems like a giant heat sink...would take FOREVER to heat up i think, but once it WAS heated up, it would probably stay warm for awhile.

i haven't followed the hardi board thread lately, but if i recall, many ppl ended up having trouble with it.

just my opinions of course, as i really have no idea how well it would work.

[autobonifica]

long story short

anything CAN work...just some work better than others

the concrete will absorb an astronomical amount of the heat you're putting into your oven...the thinner the material...the less time it will take ot heat up.

personally...i used 26 guage sheet steel (smallest i could get locally.)

[drnez]

Ya, after I posted this a did a bit of research and found that maybe it wasnt the best idea. So I decided to go with a fridge conversion. The local Home Depot sells 24"x36" 30ga galvanized steel sheets. $70 for 12 of them, should be enough I'd think.

[donafams]

Originally Posted by autobonifica

thinner the material...the less time it will take ot heat up.

personally...i used 26 guage sheet steel (smallest i could get locally.)

glad you said that, i ordered the same stuff, but was thinking it was to thin after reading others that used 18ga

[donafams]

btw, i have seen 800deg brick pizza ovens

[JTW37]

I started my first oven with 28 ga. steel. It makes a bunch of noise while it is heating and some when cooling. But it does work. I have 2 inches of mineral wool. I had it up to 600 deg. Gets a little warm on the outside, but not very much.

As for the Hardi Board, one of the guys did his with that and then ripped it out and put in steel. Took to long to heat.
JT

[donafams]

do you guys use the thin 26, 28 metal on the outside also?

[defed]

the thin steel on the outside should be fine....especially if it works on the inside. i'd have preferred thicker on the inside, more stable i would presume, but i used what i had, and that was 26ga. haven't fired mine up yet. i had thoughts of using steel siding on the outside of mine. it's pretty cheap, already painted and purchased to the precut inch.

brick would be good (probably) for an oven in general...it takes a long time to heat, but it holds its heat. the pizza oven is on all day, so once it's heated, probably takes less energy to maintain it. just a ton to get it up to temp.

[drnez]

I suppose the cinder block oven would work well if I was running my shop all day, and it was constantly being used. But thats not the case for me, I'll be firing it up on the weekends for 20 minutes at a time.