Fire brick arch - before or after first clay layer?

[tebano]

Hi all

I got a lovely firebrick arch but I am struggling to decide at which stage to put it in place. I've seen some people doing before the first clay layer by creating a sand form between the dome and the arch; others put it after cutting the door on the first layer.

Any advice would be greatly appreciated.Thanks

[devontiger]

tebano, pop up a picture or two.
Most peeps need pictures. Me especially.

[tebano]

I have now done the first layer and cut the door, currently leaving the sand in for about 5 days before I take it out and attempt the chimney and arch. Hopefully it will be ok!

I will do the insulation layer with clay, sand and straw, about 4 inches. Some peopled third layer, similar to the first one, is this necessary?

[tebano]

another query! (sorry guys)
I got a stainless steel chimney but I wonder if it is a big too big and heavy for my oven of 760mm internal diameter. The chimney diameter is 150mm. I will put it between the brick arch and the internal layer of the oven.
Any thoughts appreciated.

[downunderdave]

The pipe diameter is correct for your sized oven Regarding weight the pipes are usually made from 0.55 mm 304 stainless. There’s no reason it couldn’t be thicker apart from the fact that a thicker pipe will have much more power when expanding. You should, even with the lighter weight pipe, make allowance for its expansion or expect cracking around it.

[tebano]

Great thank you!, we are going to do the arch and flue today, I will post pictures later

[tebano]

I now fitted the chimney and the arch, things are taking shape!
drying time and then the insulation layer...