Announcement

Collapse
No announcement yet.

28" homebrew cast oven in walled enclosure Belgium

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Kris S
    replied
    Dry stacked the hollow blocks, later filled every other hole with concrete.

    Click image for larger version

Name:	f4.jpg
Views:	549
Size:	135.0 KB
ID:	436277

    Leave a comment:


  • Kris S
    replied
    Thanks David S & Mullster for your tips.

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

    Leave a comment:


  • Mullster
    replied
    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.

    Leave a comment:


  • david s
    replied
    Originally posted by Kris S View Post
    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.

    Leave a comment:


  • Kris S
    replied
    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?

    Leave a comment:


  • Mullster
    replied
    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

    Leave a comment:


  • Kris S
    replied
    concrete slab poured...
    Click image for larger version  Name:	f3.jpg Views:	0 Size:	104.8 KB ID:	436085
    Click image for larger version  Name:	image_94129.jpg Views:	4 Size:	123.1 KB ID:	436081 Click image for larger version  Name:	image_94130.jpg Views:	4 Size:	104.6 KB ID:	436082
    f3.jpg
    Last edited by Kris S; 03-08-2021, 04:08 AM.

    Leave a comment:


  • UtahBeehiver
    replied
    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?

    Leave a comment:


  • blink
    replied
    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.

    Leave a comment:


  • Kris S
    replied
    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.

    Click image for larger version

Name:	1.jpg
Views:	1150
Size:	143.2 KB
ID:	435923

    Leave a comment:


  • Boogie-D
    replied
    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

    Leave a comment:


  • Boogie-D
    replied
    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
    Last edited by Boogie-D; 02-20-2021, 08:45 PM.

    Leave a comment:


  • Kris S
    replied
    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!


    Click image for larger version  Name:	plan1.JPG Views:	21 Size:	140.7 KB ID:	435498
    Attached Files
    Last edited by Kris S; 02-22-2021, 12:35 AM.

    Leave a comment:


  • Kris S
    replied
    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.

    Leave a comment:


  • david s
    replied
    Originally posted by Kris S View Post
    I still have plenty of questions:

    1)
    Can I put the concrete slab directly on the dug out soil (with plastic foil underneath), without first putting a layer of compacted gravel under it?
    We do not live in an earthquake area and my soil is pretty hard and sandy – loamy. The oven being a cast instead of heavy bricks, with a lightweight enclosure made of hardiebacker panels shouldn’t be too heavy? We usually don’t get a lot of frost around here so I’m not too worried about frost pushing the concrete slab upwards.

    2)
    Si
    nce the oven will be enclosed, is it necessary to put a 5cm / 2” vermi/percrete insulation layer on top of the 5cm / 2” fireblanket insulation to act as 1) insulation and 2) a firm surface on which to put the final cement based render?
    is it possible to skip the vermic/percrete layer and final render layer and instead just add 5cm / 2” fireblanket extra, so: cast + 10cm / 5” fireblanket. And then just enclose it?

    3)
    I like the idea of a removable chimney, that way I could get away with keeping the walled enclosure lower, and making it less bulky. This is one design I kinda like, and it looks like a low profile roof with quite a short chimney. So I was thinking of a removable cover stone on top to access the ‘free standing’ pipe and insert / pull it out when in use / not in use. Is this a good idea? Anyone done anything like that?



    Click image for larger version

Name:	thumbnail_image.jpg
Views:	1354
Size:	166.0 KB
ID:	435376
    Vermicrete insulating slab copy.doc.zip Click image for larger version

Name:	image_83170 2.jpg
Views:	1485
Size:	146.2 KB
ID:	435388

    It depends somewhat on the soil you are laying your concrete foundation slab on to, but yes generally you need to compact it with some aggregate first.
    I don't like those thin 100mm solid blocks, give them a decent push and you'd be able to knock them down. However for the size of your oven I think the 150mm wide hollow blocks are sufficient, no need to go to the wider 200m blocks. By filling the cores with concrete you tie the blocks together and produce enormous strength especially if some steel bar is used as well.

    The big advantage of the enclosure is that you don't have the issues of drying verm/perlcrete insulation. The enclosure can be filled with dry loose perlite or vermiculite over the blanket.

    It is generally recommended that a 5:1 vermicrete be used for the underfloor insulation. Anything leaner is not considered strong enough to take the weight of the over sitting on top of it. The mix over the dome however is better at a 10:1 mix as anything richer is a poorer insulator (if doing an enclosure you don't need a a wet mix over the blanket)

    Leave a comment:

Working...
X