28" homebrew cast oven in walled enclosure Belgium

[Boogie-D]

Looking good Kris... I hope to be at this stage soon...

[Kris S]

Dry stacked the hollow blocks, later filled every other hole with concrete.

[Kris S]

Thanks David S & Mullster for your tips.

Any left over sand from the sandcastle will go straight to the children's sandbox

[Mullster]

Kris S one tip I would give is to think about your total sand needs including for the dome to cast over. I have been left with a lot of leftover sand from the dome because I bought the coarser (builders) sand. I’m not sure but I think it would have been possible to use the finer sand (plasterers) for the dome to cast over and then remove it and reuse for the final layering of the outer layer on the oven.

Having said that you are going for enclosed aren’t you - so you may be able to reuse it anyway on building your enclosure.

anyway - point still stands - think about total sand needs unless you want to end up with a lot left over when you empty out the sandcastle you cast over.

[david s]

Hi Mullster, nice to see you popping by.

Concerning the bricks: I'll go for the slightly larger 14 x 20 x 40 hollow conrete bricks.

One question I have right now is what grain size of sand I should use for the cast. Shoudl I go for sand with grain size 0-2mm or 0-4mm, does it even matter much?

The larger the aggregate, the less workable will be the mix. A range of grain size is also preferable. The proprietary aggregate size for the castable refractory I use is max 3 mm. I don't think it will matter much because the high clay content in the home-brew assists greatly in making the mix pretty sticky, but I'd be going for the finer 0-2mm. If you are using any of that as a mortar then sieve out the courser sand with a sieve.

[Kris S]

Hi Mullster, nice to see you popping by.

Concerning the bricks: I'll go for the slightly larger 14 x 20 x 40 hollow conrete bricks.

One question I have right now is what grain size of sand I should use for the cast. Shoudl I go for sand with grain size 0-2mm or 0-4mm, does it even matter much?

[Mullster]

Hi Kris - great to see your build underway and really glad my thread gave you some info. Let me know if any questions on what I did on mine - there are plenty of way more experienced builders for any general questions though!

Just addressing the bricks I used for the stand - to be quite honest I was limited by the fact it was early in COVID and building supplies were impacted. I’m confident the structure has turned out strong though with the E formation.

good luck with the build

[Kris S]

concrete slab poured...


f3.jpg

[UtahBeehiver]

Yep, several builders have just poured in dry perlite or vermiculite in the enclosure. Blocking out the corners with spacers, IE plastic soda bottles or scrap sheet rock. Are you talking leca balls as aerated clay?

[blink]

If the dome is going in an enclosure wouldn't it be easier to skip the 100mm concrete insulation layer and just loose fill the enclosure with loads of cheap insulation?
I'm planning something similar - a 30" dome in an enclosure with aerated clay loose fill insulation of about 150mm all round, and probably 200mm in top.

[Kris S]

Dug the foundation, it's a little bigger (1.35 x 1.5 m) than the hearth dimension (1.2 x 1.3 m).

Pouring the slab is for next weekend, maybe.

[Boogie-D]

I like your idea of a reveal on your decorative arch for a storm door... might be useful for smoking food too.. we have pretty similar plans and at similar stages... I’ll be following along... cheers

[Boogie-D]

Aloha Chris... I am somewhat stuck in this area too.. and trying to figure out the galley length... waiting for feed back too... at least you know your chimney size... I get so confused with my 33.5 oven and the conflicting advice in chimney but I am leaning towards a 6 inch chimney diameter too..

then in an effort to keep the galley short and easier to work with I am going to add enough room for casting as your thinking... in my case 2 1/2 thick but to the front and back of the pipe so totaling 5 inches for me..

my thought process too is the diameter of chimney plus casting room then can figure out galley floor... I am thinking if I go with 6 inch chimney... add 5 inches for my casting... then 11-12 inches should do my galley floor.. 12 inches galley floor would accommodate a resting place/warming place for my 12 inch pots and pans... but I am still waiting for the expert advise here

[Kris S]

So here's what I think it would look like: any gross errors?

5cm / 2" wall
10cm / 4" fireblanket (no vermicrete or final render layer because oven will be enclosed)
oven opening 48 cm / 19"
vent gallery would be like 2.5cm or 1" wider dan the oven opening to have a rebate for the door
likewise the decorative arch would also be a bit wider so I can put in a 'storm door' during winter.
over the vent gallery I would reduce the insulation to 5cm / 2".

my main question is about the depth of the vent gallery (correct terminology?): the single walled chimney will be 15cm / 6" in diameter so at the moment I'm thinking 5cm / 2" either side the chimney makes for a 25cm / 10" vent gallery depth.
Does that sound about right?

thanks in advance for feedback!

[Kris S]

Thanks for your reply David!

Allright, I'll stick with the 14cm wide hollow bricks.
Also better safe than sorry, so I will look into putting some compacted gravel under the slab.
I'll use a 5:1 ratio for the underfloor vermicrete (instead of 7:1)

So, when enclosed, I can skip the vermicrete insulation, that's helpfull.


Still undecided about the chimney pipe, any thoughts about a removable chimney pipe anyone? I would like to avoid a chimney pipe that's too high, but understand it might be necessary to create a good draft for the smoke. The chimney height in the above picture looks rather short imo.

What I'm most unsure about is how to flash the area where the rectangular chimney walls and the other parts of the roof come together.