Carbon Steel for flue?

[Pompeii Nate]

Today at work I picked up a big metal box that was just going to be thrown out as garbage. I brought it home thinking I would be able to use it to fabricate into a flue for my oven. I am told that it is carbon steel and would work for fabricating a flue but I wanted some more input. Can anyone recommend if carbon steel would be good enough metal/the right type material? Will this withstand the temps that the flue will reach? (what temp is that on most ovens by the way?)? I spoke with a friend who is a welder and he thinks it should work if it is just the chimney and didn't get too hot. I mentioned "hundreds of degrees" and he wasn't totally sure. The metal is probably less than 3/8ths inch thick or maybe a bit less. Not too heavy but not real flimsy.

Ideas? Thoughts? Concerns?

Thanks,
Nate

[brickie in oz]

Re: Carbon Steel for flue?

The thing will rusts out after a few firings, we tried a normal steel flue some years ago and it lasted weeks.
Your being thicker it will last a while before it rusts away.

[david s]

Re: Carbon Steel for flue?

I bought a pot bellied stove years ago and the stainless steel flue was going to cost more than the stove so I put in a 0.55 mm galvanized flue. It was corroded by the end of the winter, so I replaced it with boiler tube, about 4mm thick from memory. It lasted pretty well, but I sold the place a couple of years later so don't know about it's long term durability. Get stainless in the first place then forget it.

[Laku]

Re: Carbon Steel for flue?

It's not the heat alone but the acidity of flue gasses that will eat steel over time. Unless you can get it fabricated from stainless steel, I'd save myself some trouble and just buy ss one.

[Laku]

Re: Carbon Steel for flue?

Must be something to do with heat dissipation.

I think I read somewhere that the oxidation(rust) of the steel will form a protective layer that will in turn slow down the corrosion.

[Mike D]

Re: Carbon Steel for flue?

What about copper?

[Gulf]

Re: Carbon Steel for flue?

What about copper?

Sell the copper $$ and buy SS .

[david s]

Re: Carbon Steel for flue?

Too soft IMO

[Laku]

Re: Carbon Steel for flue?

And maybe, by the time enough steel in a thin flue has corroded to form the protective layer of rust, there isn't much steel left to protect?

That's how I figured it.

[Manolo54]

Re: Carbon Steel for flue?

The rust formed in carbon steel is not really protective...it will allow the steel to continue oxidizing until it is consumed

[Pompeii Nate]

Re: Carbon Steel for flue?

Ok so it sounds like the carbon steel by itself is a bad idea. But let me now ask this...what if I sprayed it with the high temp spray liner that can be purchased at an auto parts store? The kind that is used for exhaust systems or other high temp demands in vehicles? Will that solve the problem of corrosion? Will that cause it's own problems like fumes? Flaking? Or anything else? It was a recommendation that someone made to me (not from FB or the forum) so I thought I would see what everybody thinks.

Thanks!

Nate

[brickie in oz]

Re: Carbon Steel for flue?

Can you eat it and safely ingest it?
If the answer in no, then dont do it.

The amount of effort and time you have spent trying a work around on this you could have bought some SS flue cheaper.

[Pompeii Nate]

Re: Carbon Steel for flue?

Hey Al,

Luckily the only thing spent so far on this idea is the time it has taken me to write the questions and read the answers. No money or time has been spent on purchasing material or fabricating anything so at this point I am out nothing. I will have to see about the SS option. I checked yesterday with a supplier for single- and double-walled metal flues and I might just go that route. Anyone see any problems with going with a single-walled metal flue and then putting insulating blanket around it? Is the insulation around it even necessary if I brick it in? Thanks for your input!

Nate

[brickie in oz]

Re: Carbon Steel for flue?

Hey Al,

Luckily the only thing spent so far on this idea is the time it has taken me to write the questions and read the answers.

Time better spent doing other stuff, drinking beer, playing with the kids, making love.

Its all been done before, thats why they all use SS flue.

[Pompeii Nate]

Re: Carbon Steel for flue?

Thanks for the advice Al! Unfortunately with a wife who just gave birth two weeks ago yesterday there isn't much love-makin' going on around here currently. Oh well, I guess that gives me more time to think about an oven to keep my mind off of it.