Scotty's 36" Build on the Sunshine Coast, Australia.

[Aussie Pete]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Hey scott, build looks great, with your issue with the door, i think the norm is to sandwich a board of calcium silicate inbetween 2 sheets of steel. I suppose if you did that, you could do a 6mm steel back of door (facing fire), then the silicate board,then you could have the stainless facing outward if you wanted the stainless look.
You can get the board pretty cheap around Brissy. Its only about $25 for a 1" board 1000 x 500mm. Just use 2 layers to get 2" thick insulated door. thats similar to what i'm thinking of doing anyway.
Keep up the great building.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Came home tonight after about 9 hours since I did the above rendering and there are some substantial cracks in the render and it feels a bit loose or it seems to float on the blanket still. It is still a bit wet so I know its still setting, but will the cracking eventually stop on the render? I assume I have to do a few coats of this stuff, how thick should it go??
Cheers
Scotty

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

wrapped with an inch of ceramic blanket.



First layer of render nearly done, for this im using 10 sand/6 Fire clay/3 lime/2 cement. the same mix I used for the brick mortar, but I used 5 water/1 Bondcrete for the water to mix the mud. At the moment its about an inch thick.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Bloody good point on the fibres. I had not thought of that!
Ok back to the drawing board for the door, I have 2 laser cut door coming anyway one in 6mm and one in 3mm, Im sure I can come up with something to use the stainless.

[david s]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Scotty,
When you get rid of most of that water the oven will heat more evenly. It is a bit like a wet sponge sitting outside to dry. The top half will dry out while the bottom half is still wet- have patience.
6mm of any insulator is not thick enough. Cement sheet will not cope with the heat and the fibres it contains may not be safe. An uninsulated door will work, but not as well as one that is insulated. Traditionally Italian ovens had wooden doors. These work quite well as wood is a way better insulator than steel. The trick was to soak itin a bucket of water to reduce charring. Another trick they used was to stuff wet newspaper around the door to make a really good seal.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Hey David,
Thanks for the tips. I was thinking that the lower walls were cooler cause the heat from the burner went straight up thus heating the roof first? I did go thru a full bottle, amazing actually I got about 28 hours out a a already partially empty 9KG bottle, I was quite surprised.
Now as for your comment of the door, "Heavy uninsulated steel doors provide a good path for conductive and radiated heat loss"
is that a good thing or bad?? Will the bit of 6mm cement sheet do the job of insulation or should I use a thicker sheet or something else?
Thanks a heap for you help tho.
Scotty

[david s]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

For your sized oven you should burn at least one full bottle of gas. As your temps indicated, there is still tons of water in the lower part of the dome and floor. Some kind of makeshift door, partially closed, that will still allow some oxygen in will help to keep in heat. I use one made of ss as shown in the thread on curing.

Regarding the ss door you plan on making, remember that ss warps way more than mild steel when heated, but I think 6mm will prevent that. Heavy uninsulated steel doors provide a good path for conductive and radiated heat loss.

[brickie in oz]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Light some small fires, dont go the whole Devil fires just yet, small and low, for a week or so.

Hey that has a ring to it.....

The gas burner is only good to a point.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Al,
when you say curing fires, do you think I should actually light a fire in there or just continue with my ring burner, turning up the temp each time??
Thanks

Scotty

[brickie in oz]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Ill leave it for a couple days now before I wrap it in the insulating ceramic blanket.

Prolly best to some curing fires before you insulate otherwise you just trap the moisture in the oven.
It takes months for the oven to come good with no moisture in it.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

More of the Curing process,



Found this today at the shops, could have saved myself a heap of trouble.



Got an 8 inch 6 foot long flu coming and have my local laser cutter cutting me some 3mm stainless to cover the facia and my door is going to be a bit 6mm cement sheet sandwiched between 6mm Stainless on the fire side and 3mm stainless out side, getting the idea of hot forging some big copper rivets to hold it all together.
Also ordered today all the 30mm sandstone tiles for the slab surface, I will seal it with a wet seal to bring out the grain of the sandstone.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

So I got my extra bricks and spend last weekend cutting in the last ring and then the middle brick. So fiddly


I waited for a day and then started the curing process, I know probably didn't wait long enough.....



Got myself a gas ring burner and left it running on low for 24 hours.



Temp got to after 24 hours 80 Deg C on the lower sections and up to 180 Deg C at the inside of the dome, the heat soaked thru after about 10 hours to the point that I had to hold back the tears if I put my hand on the out side of the top on the dome.
Ill leave it for a couple days now before I wrap it in the insulating ceramic blanket.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Ok, Flue opening modified today thanks to Doug and his guidance.

And today I ran out of Fire Bricks!! with only about 4 more full bricks needed Its chewed up 175 Fire Bricks so far and I reckon I've only wasted about 2-3 in cut off wastage.....
Tomorrow back to the brick joint for another 10, just to be sure!.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

I am going to get a sheet of 6 or 8mm stainless laser cut to cover the facia bricks up around the arch, I thought that the bit that gets cut out of the middle will obviously fit the door opening. My question is would a bit of 6 or 8mm stainless with some form of handle and leg to stay upright suffice for the door? will the heat warp the stainless?
Thoughts.

[scottsummers]

Re: Scotty's 36" Build on the Sunshine Coast, Australia.

Hey Doug, thanks for the heads up, it will be hard to make it any wider (left to right, it's currently 3 bricks wide) but I think I could make it thicker with a bit of ease. I'll cut into the front course of bricks tomorrow to make it 100mm front to back? I have a 2m 150mm stainless flue that will sit ontop, so that should draw well?
I'll make the adjustments tomorrow.
Thanks again.
Scotty