Mr Gs Aussie Castable oven.

[mr g]

Re: Mr Gs Aussie Castable oven.

Good luck ecoscapes, keep us updated and post any photos you have.

[jbriggs]

Re: Mr Gs Aussie Castable oven.

Mr G.

How have the ovens been doing?? I plan to do almost the exact thing that you have done, thank goodness I found this site!!! I have found a Harbison-Walker distributor that has everything that I need for a very reasonable cost. What castable did you use??

Also, what is the I.D. of your oven and how high are the walls/dome peak? Did you choose to angle the sides slightly inward to closely resemble the soldier course on a brick oven and allow less turbulance?

Did you strictly follow the curing process or did you find that simply lighting gradual fires until your were comfortable "letting all hell break loose" was suffcient?

Sorry for all the questions!

Thanks! Jason

[mr g]

Re: Mr Gs Aussie Castable oven.

Hi Jason, don't apologise for questions, we love them !!

The ovens have been doing well although we still haven't got a lot of data on their performance. My beach house oven is still at the stage of curing fires. I'm not there every weekend so I still haven't been able to cook in it yet although there might be some action this Sunday. One of my friends has had his one firing so hot that the floor tiles were glowing red and the oven held up beautifully. The refractory concrete we used is Vesuvius brand. I can get specifics for you if you need but I'm not sure of it's availabilty overseas.

The Internal diameter of the oven is 1000 mm and the height once the floor tiles have been laid down is 450 mm. The side walls are approx. 300 mm high. I made the walls straight rather than curved like a pure dome so that there is more room for things like roasting trays and the like. I wish I could say that it had to do with turblence and heating efficiency and so on but I just liked that shape. The design was a comprimise between a typical Tuscan oven and the Pompeii.

As for the curing process I got the feeling that following the strict method was going to be impossible for me and it may also a way for the refractory producer to cover themselves in case of product failure so I just used the "slowly increasing fire method". So far so good.

Good luck with your build.

Regards,
Mr G.

[david s]

Re: Mr Gs Aussie Castable oven.

Don't rush the curing. You can try the gas burner method which is much easier and ramps the temp up slowly and evenly. A 24 Hr burn with my burner takes the temp up evenly to 250 C then I go to wood fire for last two days to get to 400 C

[mr g]

Re: Mr Gs Aussie Castable oven.

Yep, I've got a gas burner. I'll try that method - sounds safer.
Should I see any steam or condensation on the outside of the dome?
Thanks.

[jbriggs]

Re: Mr Gs Aussie Castable oven.

Right on. We have the same thoughts regarding the shape. Mine is almost identical in size/shape (on paper that is.. ), simply because I wanted the best of both worlds, meaning the higher sides, and a lower arch. I plan to use the 12" floor tiles as well, but the only thing I cannot decide on is the opening/arch. Part of me wants to cast the dome and sides, but brick the entry and fule section. Or, cast the entry as well but add a brick vaneer for looks.

Also not sure about the flue. I want to go with the 8" round stainless but man is it expensive compare to the readily available terracotta flue. I think casting would be cool since you can really customize how you want the flue transition to work in regards to funneling the exhaust gas/smoke.

I too was planning on using a large burner to better regulate the heat for curing, until I reach the point that I need to hold it at operating temp for 6 hrs, then crank up a few "hell raising" fires.

Oh yeah, The castable I will use is Harbison-Walker KS-4V, or possible another of their products called Mizzou. They are both around 140lb/ft^3, 2600-3000 degree, which very closely matches the properties of a medium-duty fire brick. I wil insulate with a 2" cal-sil board under the hearth, and a 4" 8# wool blanket. I know 2" of blanket will do it but they had a deal on some left over 4" so what the heck!!!

[mr g]

Re: Mr Gs Aussie Castable oven.

Another couple of curing fires under my belt now. I used a gas ring as was suggested and I got the oven to approx. 200 Celcius. The insulation works like a charm from what I can tell because the outside was still cold to the touch. It will be intersting to see how it performs at high heat.
I've actually already put on two coats of finishing reder but my camera had flat batteries so only pics of the vermiculite for now. More photos to come soon.

Regards
Mr G.

[mr g]

Re: Mr Gs Aussie Castable oven.

I'm posting some updated photos. I've since used the oven for pizzas, breads and roasts and I am extremely happy with the performance of the oven. At the moment I have placed the thermometer on the temporary door but I will eventually place it on the side of the oven. Does anybody know whether I should use a copper sleave that the thermeter should sit in?

Cheers
Mr G

[Johnny the oven man]

Re: Mr Gs Aussie Castable oven.

You should be OK, but if you decide to go that way, give me a call
on 0451470371 John

[david s]

Re: Mr Gs Aussie Castable oven.

Copper is an extremely good conductor so if you use it you can expect heat to be efficiently conducted from the inside of your oven to the outside. I used a 1/2' copper pipe for my sleeve, but wish I'd used stainless steel. Google metal conductivity and you'll see that stainless is a much better option.

[JoeyVelderrain]

Re: Mr Gs Aussie Castable oven.

Awesome!
great job Mr. G.
I miss the learning process, I wish I had an excuse to build another one, I would use your thread as a guide.

[mr g]

Mr Gs Aussie Castable oven.

We've finally done something about the oven door. It's made of cast aluminium (Aussie spelling) with a space for insulating material inside.
We will use a thin sheet of metal to cover the insulation and we'll use
two steel handles with wooden sleeves.

I've also attached a photo of the wooden pattern for the door.

[BackyardPermaculture]

Re: Mr Gs Aussie Castable oven.

Nice work on the aluminium door - looks good on the kitchen bench too

[david s]

Re: Mr Gs Aussie Castable oven.

Mr. G.
That's fantastic. How did you go about making a mould for the cast?
Dave

"kindled with zeal and fired with passion"

[mr g]

Re: Mr Gs Aussie Castable oven.

Hi David, a photo of the mould is included with the aluminium door. It's simply made from mdf.

Cheers
John.