Chimney Temp for construction

[kriso]

Can anyone tell me what temperature the inside of a chimney reaches as I am looking at making the transition to the flue and I am looking at braizing it with easyflo. Would it reach over 500C.

[david s]

Re: Chimney Temp for construction

No, nowhere near it. The inside of the chimney remains black and that burns away at around 330 C. Unless of course you overload the oven chamber with fuel and you allow flames to roar up the chimney. Even then I doubt if you would reach 500 C.

[kriso]

Re: Chimney Temp for construction

Thanks for that, I am going to go ahead with the fabrication with brazing which I can have a crack at myself. will post some pics of the process.

[david s]

Re: Chimney Temp for construction

Stainless steel is difficult to braze. You will need oxygen/acetylene or oxygen/LPG. Good luck.
An easierbalternative would be overlapping joins using stainless pop rivets.

[kriso]

Re: Chimney Temp for construction

I was thinking of making the base part of the vent out of normal steel that can be brazed and have had the flue and chinaman's hat cowl made out of stainless steel. I have attached a pic of someone else's from FB which I think would work on mine. Any thoughts on having different metals?
Thanks

[brickie in oz]

Re: Chimney Temp for construction

With that sort of set up in the pic you will probably get more smoke out of the door than up the flue.

[david s]

Re: Chimney Temp for construction

ok, yeah that will work, but mild steel will corrode. if it's thicker as it appears to be, it will last longer.

[david s]

Re: Chimney Temp for construction

With that sort of set up in the pic you will probably get more smoke out of the door than up the flue.

yes, a much steeper angle would collect the smoke better.

[kriso]

Re: Chimney Temp for construction

More smoke out the door that chimney, why??? Definitely not the desired outcome that I want. With all the work put into the oven so far to fail on the chimney would suck..... Please send me some suggestions...

[david s]

Re: Chimney Temp for construction

you need a funnel to the flue pipe.

[kriso]

Re: Chimney Temp for construction

Thinking about this, the funnel is the whole point to the chimney, to draw or funnel the smoke out.... What height would be the min for this to work???? And could this be made in galvanized steel or does it have to be stainless like the rest????? or maybe refractory cement???? Cheers

[GianniFocaccia]

Re: Chimney Temp for construction

More smoke out the door that chimney, why???

Consider the smoke exiting the oven that can't find it's way to the 8" diameter flue. It's gonna find the path of least resistance, out the front of your entryway. A flat arch like the one pictured allows a smoke path much wider than the flue pipe above it. The purpose of the funnel is to collect and direct the smoke upwards along a natural path before it can find the front of the oven and the fire builder.

[david s]

Re: Chimney Temp for construction

I think using a castable refractory is the easiest, but that's because I use the stuff a lot and have had lots of practice making moulds. If you make a mould from damp sand, you can simply plaster the castable over the mould about 3/4" to 1" thick, then remove the sand. It can be cast in situ. The castable should be wrapped in plastic (I use clingwrap) for 24 hours, you don't need an extended curing period with castable refractory. This stuff will take the heat and won't corrode like steel will.You can cast to whatever form you want to make. About 45 degrees is about optimum.

[brickie in oz]

Re: Chimney Temp for construction

And could this be made in galvanized steel

Dont use gal, you will poison yourself with the fumes as it burns off.