Stainless stack turning black

[SeanD]

My shiny new stainless stack has gone from shiny, to copper, to now close to black. Is this typical? Are all the shiny setups I see in people's pictures that way because they are still brand new or do people clean their stacks after the season?

Sean

[adk1]

I would think that depends on if it is double walled or not wouldnt it?

[SeanD]

Sorry, it's single wall.

[Brent]

It all depends on how hot you run it. If you don't exceed 1000 deg stack temp with an internal probe thermometer, it will stay shiney longer. If you crank up the heat you will get the colour changes.

[SeanD]

That's what I figured, but my Condar insert-style says I peaked at 900 or so, but mostly I was running between 6-800. I have a feeling it's off.

[johnallin]

Brent,
I don't have a stack thermometer, and mine turned almost purple within a few short weeks last year. Too much heat lost up the stack I guess, eh?
What's the cure on a 2x6?

[WESTVIRGINIAMAPLER]

Mine is discolored but that is a good thing. It has made close to 600 gallons of syrup in the last 8 years and most years of running stack temps between 1200 and 1750 degrees throughout the boil. I think it will still last many more years as it get no moisture during the off season.

[PerryW]

My shiny new stainless stack has gone from shiny, to copper, to now close to black. Is this typical? Are all the shiny setups I see in people's pictures that way because they are still brand new or do people clean their stacks after the season?

Sean

Mine turned copper colored after the first season and stayed that way. It's probably 12 years old now. I am guessing I got it too hot, but it still seems to be holding up.

[Southtowns27]

My stack is all kinds of colors - bronze, blue, purple - on both of my evaps. It means you're firing it good :)

[Dill]

Mine's purplish, I just thought that was the color they turned.

[SeanD]

Well, I guess I'm in good company. I should have taken more pics before working her over. It may not be pretty, but it does it's job.

Sean

[SeanD]

I'm wondering how far off my thermometer is. If I've peaked at 800 deg. on the thermometer what is it really at? Does anyone know at what temp. stainless darkens or blackens?

Sean

[markcasper]

You need to remove the plastic from the stack, if you don't it will turn an icky brown like mine.The sections that had the plastic removed look like new yet

[SeanD]

There wasn't any plastic on it.

Sean