Mr Gs Aussie Castable oven.

[TapRackFire]

Great build Mr. G,

I am torn on how to do my dome. If I built one like yours, do I need to add rebar to it? Would that not make it stronger? I have thought of using a steel dome from a propane tank and covering it with refactory concrete, but having trouble finding a dome large enough.

[david s]

You could try rebar, but the recommended reinforcing is stainless steel needles, presumably for a reason. Better to stick with what's recommended IMO. Mild steel will be prone to rusting in time. High temp will accelerate any reaction and rusted steel expands in volume creating stress points and fractures.

[david s]

The purpose of the fine fibres in the castable mix is not to provide strength because they melt at 160 C and then burn away leaving a network of tiny pipes that can safely eliminate steam.Some manufacturers use natural fibres that just burn away, others use polypropylene fibres that melt then burn. These are different to the stainless steel fibres that are added to provide extra strength.

[Aussie Pete]

great ovens Mr. G, surely your not a novice at this, you've done a fine job.

I have a quick question, i am doing a castable dome also (over sand), i think i might add some stainless needles in my mix, does anyone know where to get around brisbane, or what kind of supplier to go through. is there a thread on here somewhere, that goes into more detail about them, (such as size of the needles & quantity in the mix).

Mr. G, do you have pics of how you transitioned your thermometer into your dome.

[david s]

add 2% by weight. Try Antec Engineering.FIBR446/25-C

[Johnny the oven man]

Originally Posted by david s

add 2% by weight. Try Antec Engineering.FIBR446/25-C

2% is lighter than the normal 2.5% that is recommended for refractory work. I would be going higher, useing about 5%.

[Johnny the oven man]

Originally Posted by david s

add 2% by weight. Try Antec Engineering.FIBR446/25-C

2% is lighter than the normal 2.5% that is recommended for refractory work. I would be going higher, useing about 5%. there is a product called fibrestone, made by Sila in Perth that uses 60% s/s fibres. It is used for very high load areas. A high % wont hurt a dome.

[mr g]

Hi guys, I might have photos of the themometer installation but there wasn't much science to it. I simply drilled through the outer shell with a masonary bit without the hammer action and when I got to the inner refractory shell I switched over to hammer. I installed it beside the oven entrance so I could read it easily.
I haven't used any needles or certainly no re-bar. We have had a few ovens going now for a couple years with many dozens if firings with no cracking what so ever. The only thing I would change with the design is an 8 inch flue instead of a six inch flue.

p.s - I had no previous experience so if I can do it anybody can.

Cheers for now.
Mr G.