New 36inch castable build in Brisbane

[oasiscdm]

Re: New 36inch castable build in Brisbane

David.

I would has at a guess its the rough roads and speed humps.

Looking at Brissie's photo's he has has plenty of support. I would use Hebel adhesive instead of liquid nails as Hebel adhesive creates one solid mass whereas the liquid nails won't.

Shame brissie I have enough adhesive left but your along way away.

I found it cheaper as I needed mini mix, worked out a little cheaper. Mixing the concrete yourself though well no comparison. It was meant to replace brick walls and concrete floors. So is substantially cheaper than those.

[david s]

Re: New 36inch castable build in Brisbane

I agree, it's not cheap though. About 1/3 weight of standard concrete so probably about 1/3 strength too. 6 mm reo cast into it is rather inadequate IMO. Two layers should be plenty. I used 70mm Hebel power panel for my mobile oven as both structural and insulating layer, apart from the 1" vermiculite between the floor and the Hebel, in an effort to save weight. I am a bit disappointed as it's proved inadequate regarding strength. It has cracked quite badly although it doesn't really matter as it's contained in a steel cradle. Not sure whether the cracks have occurred because of heat or going over rough roads and speed bumps. Suggest if you are using Hebel to have support under the middle of it as well as the sides.

[oasiscdm]

Re: New 36inch castable build in Brisbane

Will there be no structural concrete hearth layer to support the oven, lloor is this "Hebel Powerfloor" something I am not understanding?

Gulf

If you check my base build I to used hebel to construct the whole base and heath slab.. I
Like what brissie had done though in using 2 layers. Hebel is so much easier to work than forming and laying a concrete hearth and as brissie pointed out provides added insulation.

[brissie]

Re: New 36inch castable build in Brisbane

Sorry cobblerdave,

When you mentioned tiles, I was thinking of the 10mm variety. Having read more posts in other threads I see brick slabs are labelled tiles. I guess I need to learn the lingo...

[cobblerdave]

Re: New 36inch castable build in Brisbane

Gudday
50 mm is a fair thickness so the word slab rather tile should apply
Regards dave

[brissie]

Re: New 36inch castable build in Brisbane

cobblerdave

I am using 300x300x50 fire brick slabs. Not tiles. I am still not sure on what I will do. I plan on casting the dome next weekend, I do need to decide before I start.


Thanks for the info, I will be doing a search to see if can find any brick fails...

[david s]

Re: New 36inch castable build in Brisbane

David s

Does anyone ever replace bricks on the base? What is life of a brick in an oven?

If a bricks lifetime is long, It may not be worth the effort to make the base future removable.

Steve.

Some people freak out if a crack appears and they feel the need to replace it. A cracked floor brick does not effect the performance though and is easy enough to live with.

[brissie]

Re: New 36inch castable build in Brisbane

Gulf,

PowerFloor, Is steel re-enforced aerated concrete. I has 6mm bars through it. Its an alternative to traditional concrete flooring. A single 75mm (3 inches) thick panel has an R value of about 1 (thermal resistance). The floor will be 150 (6 inches) thick. I will also have a 50mm (2 inch) calcium silicate board under the brick slabs under the oven.

The 1800 (6 foot) long boards will span from the back to the front, and allow for some overhang at the landing.

I am using this product, because it is easy to install (no form-work) cost about $70 per 1800*600 (6x2) sheet. Plus it adds an additional layer of insulation.

Steve.

[Gulf]

Re: New 36inch castable build in Brisbane

Just a photo showing the first half of hebel PowerFloor board. The second half will be placed and then covered with two full boards. The full boards will be stuck to the lower broads by liquid nails, and mortar around the edges to the blocks.

Will there be no structural concrete hearth layer to support the oven, or is this "Hebel Powerfloor" something I am not understanding?

[cobblerdave]

Re: New 36inch castable build in Brisbane

David s

Does anyone ever replace bricks on the base? What is life of a brick in an oven?

If a bricks lifetime is long, It may not be worth the effort to make the base future removable.

Steve.

Gudday Steve
Yes there was an oven this year a secound hand oven with broken worn hearth tiles which were replaced. I can't find it at the moment but I remember it had a gas fitting as well that had to be cut around. They were tiles too not brick. I suspect tiles might be a bit more fragile than brick and I also suspect a lot easier to replace than brick.
Regards dave

[brissie]

Re: New 36inch castable build in Brisbane

Just a photo showing the first half of hebel PowerFloor board. The second half will be placed and then covered with two full boards. The full boards will be stuck to the lower broads by liquid nails, and mortar around the edges to the blocks.

[brissie]

Re: New 36inch castable build in Brisbane

David s

Does anyone ever replace bricks on the base? What is life of a brick in an oven?

If a bricks lifetime is long, It may not be worth the effort to make the base future removable.

Steve.

[david s]

Re: New 36inch castable build in Brisbane

It makes little difference whether the dome sits on the floor or around the floor. The advantage of having the floor inside the dome is that replacement of floor bricks is easier. There is more brick cutting required if the floor is inside the dome. Make sure you insulate under both the floor and dome sections.
The easiest way to cast a one off is to cast the thing in place over a sand dome mould which is then removed after the castable has set. Using wet newspaper between the sand and the castable leaves you with a pretty clean surface. Be careful when mixing a batch of castable as it goes off pretty fast. It is quite temperature dependent so start mixing small amounts at a time until you get the hang of it. Do not leave the bags in the sun to pick up heat prior to mixing. If it's quite a hot day then use chilled water. Cover the casting as soon as it's completed. The reaction is over in 24 hrs so you can remove the sand mould the next day.

[brissie]

Re: New 36inch castable build in Brisbane

Next weekend is a long weekend, I have 3 days to play with. So I might cast the dome. I am thinking of casting the dome into 3 or 4 sections, and also separating the flue structure from the main dome to reduce heat loss through the opening.

I have most of the materials required. The castable is made in Thailand, 12*20 kg bags. I think I will keep 3 bags for the opening, and patching over the dome section joins. I also have Corfix 900 degree mastic to seal the sections to each other, and perhaps to the floor.

I have question. Is it best to seal the dome to the floor? The floor will be 300x300x50 (1foot x 1foot x2 inches) brick slabs. Or is it best to cut the bricks to fit inside the dome.

More photos of the base...

[brissie]

Re: New 36inch castable build in Brisbane

Have completed the base blocks and bond beam. The beam across the opening has 12mm and 16mm deformed bar for strength. You can't easily bend 16mm, so the 12mm is used to wrap around the structure, and tie it down to the base. Only the corner vertical cores are filled with concrete and steel.