New Oven

[HungryHVAC]

Wish I found this site 3 weeks ago, it would have saved me allot of head scratching. I do not claim or want to be a mason way more skill and work than us knuckle dragging HVAC guys want. How long should I wait to start building oven? The hearth slab is 6” and was poured 4 days ago and the oven slab is 2” 5:1, 2” ceramic blanket 2” 8:1 that was poured 36 hours ago.

[UtahBeehiver]

Yes it too bad you did not find us. There are some potential fatal flaws in the insulating base. Ceramic blanket is not used for floor insulation, it does not have enough compressive strength, you need CaSi board min 75 psi at 5% compression, also the 8 to 1 layer is also weak side to support an oven. 5 to 1 is fine. One of the pics show fire bricks sitting on the concrete hearth, if you do this heat from the fire brick will transmit down into the concrete that acts as a heat sink. If it were my oven I remove the 8 to 1 , ceramic blanket and get the bricks off the concrete. Down load t h e free eplans from Forno Bravo and review before to go any farther.

[HungryHVAC]

Thanks for the feed back. I will rip out the oven floor tomorrow and order ceramic board and redo. The brick in the picture was just sitting there as a spacer for my layout. My source for the casi board only lists density as 40 or 55 it doesn’t give me a psi rating and a google search didn’t any results any insight?

[UtahBeehiver]

It would be helpful to know the brand. If it meets ASTM C 5333, Type 1 most likely you are good. Density 40 or 55 are what units. Here is an option to consider, just remove the 8 to 1 pcrete and ceramic blanket and then add a 2" maybe 3" 5 to 1 precrete on top of the bottom layer 5 to 1.. You may be able to use the ceramic blanket elsewhere, dome or dooor filler.

[HungryHVAC]

I think that’s what I’m gonna do is scrap the v-Crete and repour a 5” 5:1 slab. Then I’ll use blanket on dome.

[UtahBeehiver]

Before you start the dome why don't you give the members a chance to look at your design, IT, etc so we can help you be successful.

[HungryHVAC]

Well there’s the problem good sir, I’m flying by the seat of my pants over here. Basically going by what I know works for heat transfer and what doesn’t and going from there. Now I stumbled across this amazing resource I’m doing some deep digging before I start oven construction

[UtahBeehiver]

I suggest you download the Free eplans from Forno Bravo. It will give you a good baseline to start from on design and construction. Then go to the Newbie section of the blog and look at Treasure Achives, here are links for some of the more documented builds.