Need help with my next steps.

[Neil2]

Re: Need help with my next steps.

Any portland based concrete needs lots of water to cure. After it is cured (at least 7 days) then it will start to dry. Final drying can wait until the dome is built. Drying out the oven completely takes time and patience but is not that difficult.

[Omaharosario]

Re: Need help with my next steps.

For a 4" pour of 5 to 1 ratio vermiculite-portland, what type of portland is suggested??
N, S, O, or other. Also should rebar be used in this layer?

[mrchipster]

Re: Need help with my next steps.

For a 4" pour of 5 to 1 ratio vermiculite-portland, what type of portland is suggested??
N, S, O, or other. Also should rebar be used in this layer?

Portland cement is not graded with letters Mortars are graded with letters.

You do not want mortar you want Portland cement.

Mix by volume and not weight. I used a kitchen 1/2 gallon pitcher to make my mix. Of course it took more than 5 scoops of vermiculite an one scoop of cement.

Wet the vermiculite with about 1/2 - 3/4 gallon of water per cu ft of vermiculite then mix up a slurry of portland cement and water, thick soup like tomato soup consistency. Then pour the slurry evenly into the wet vermiculite mix with a shovel until it reaches a consistent color. after that shovel into your forms.

Do NOT!!! use a power mixer it will break down the vermiculite.

Chip

[Omaharosario]

Re: Need help with my next steps.

Has anyone used a refractory mortar called "Super Demon Air Set"? If you have, do you have any positives or negatives of this product.

[Ken524]

Re: Need help with my next steps.

You don't want to use rebar in the insulation layer.

Has anyone used a refractory mortar called "Super Demon Air Set"? If you have, do you have any positives or negatives of this product.

Please read DMUN's comments concerning premixed wet mortars on the previous page. There are better products out there for a Pompeii.

I would like to be able to reach higher temps and have a extended amount of cooking time.

What do you mean by this? The standard Pompeii oven will hit 1000F and provide usable cooking heat for nearly 3 days after firing. Do you have a goal in mind that exceeds this?

[Omaharosario]

Re: Need help with my next steps.

So have you heard bad things about this product?

[ggoose]

Re: Need help with my next steps.

I had many of the same questions when I was choosing a refractory mortar. I discovered that air set (premixed wet) mortar is water soluble, meaning if it gets wet after it has dried it will again be workable, hence it could easily be damaged . Only use mortar that 'cures' (powder form), not air drys, and moisture will have no effect on it once cured . See Build Masonry Fireboxes for a good explanation.

gene

[Omaharosario]

Re: Need help with my next steps.

I had many of the same questions when I was choosing a refractory mortar. I discovered that air set (premixed wet) mortar is water soluble, meaning if it gets wet after it has dried it will again be workable, hence it could easily be damaged . Only use mortar that 'cures' (powder form), not air drys, and moisture will have no effect on it once cured . See Build Masonry Fireboxes for a good explanation.

gene

Thanks Gene! That was very helpful in helping me understand why this product is not suggested. Also what kind of mortar did you end up using?

[Omaharosario]

Re: Need help with my next steps.

I have 72"X72" Platform, I want to use this space wisely so what would the suggestions be for my ID? Also it is a corner installation.

[ggoose]

Re: Need help with my next steps.

I used FB50 - 3 bags, and finished up with Heatstop 50 - 1 bag. Both are good; Heatstop is a bit easier to work with initially (creamier), but the FB is easy to work with once you figure out the proper consistency. The FB was cheaper for me even with shipping. I would use either again.

gene

[ggoose]

Re: Need help with my next steps.

72" - 4.5" X 2 (firebrick) - 3" X 2 (ceramic blanket) - 4" X 2 (steel studs and cement board or vermicrete or whatever you are finishing with) = 23"; So 72" - 23" = 49" for an maximum inner diameter. Decrease (X2) if you increase the abount of vermicrete, or vermiculite within an enclosure, or use some thicker material to enclose the dome (like cmu's).
Hope this makes sense...

gene

[Omaharosario]

Re: Need help with my next steps.

Has any one ever built an entire dome out of fabricated arches, 1a & 2a so on?

[Ken524]

Re: Need help with my next steps.

Has any one ever built an entire dome out of fabricated arches, 1a & 2a so on?

I haven't heard of this. Fabricated out of what? Cast refractory arches? Sounds interesting.

[Omaharosario]

Re: Need help with my next steps.

I haven't heard of this. Fabricated out of what? Cast refractory arches? Sounds interesting.

Yes, refractory arches. We used 1a "1 Arches" To achieve our solider course. It looks great for our dry fit and has me thinking this may work for the dome also. We would set them long ways on their angled side and cut them down to make our circumference. Now how to do the math to know it will work is another question

[Omaharosario]

Re: Need help with my next steps.

Should you ever soak your fire brick before laying them?