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Changing color of class A chimney

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by NortheastAl, Jan 30, 2013.

  1. NortheastAl

    NortheastAl Minister of Fire

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    I just went out and had a good look at the chimney, and just below the cap I see color change in the chimney pipe. It has the appearance of metal that has been heated. Almost like a rainbow effect to it. It only extends about a foot or so down from where it meets the cap. Is this normal?

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  2. topoftheriver

    topoftheriver Member

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    There could be some overheating, maybe, or it could be just an anomaly.
  3. TheBaron

    TheBaron New Member

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    That also happened to me a few years back with a Selkirk rigid system at our cottage. The pipe near the top got a nice rainbow effect from the heating of the metal.

    I didn't think anything of it at the time. I wonder if that is a sign that it got too hot, or normal for this to happen...
  4. lopiliberty

    lopiliberty Minister of Fire

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    picture049.jpg

    Here's a picture of mine. Its also has the rainbow effect on the top couple of inches. Its kind of hard to see with all the black up there. Completely normal. Its been like that for 18 years.
  5. topoftheriver

    topoftheriver Member

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    It's seasoned. Look OK to me. Carry on.
  6. NortheastAl

    NortheastAl Minister of Fire

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    View attachment 91557

    I don't know if you can see this, but here it is. The install is only about six weeks old.

    Attached Files:

  7. NortheastAl

    NortheastAl Minister of Fire

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    Of course, I thought I had it rotated the correct way.
  8. firefighterjake

    firefighterjake Minister of Fire

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    Normal . . . but just in case . . . look around for the leprechaun's stash of gold. ;)
    ScotO likes this.
  9. corey21

    corey21 Minister of Fire

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    Looks fine to me.
  10. Highbeam

    Highbeam Minister of Fire

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    I get a smoke scum accumulation. It looks like what you have there and cleans off with windex. All summer you get a nice shiny chimney if you clean the outside while your up there in the spring.
  11. Backwoods Savage

    Backwoods Savage Minister of Fire

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    Sleep tight tonight. All is well.
    keninmich, ScotO and milleo like this.
  12. NortheastAl

    NortheastAl Minister of Fire

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    Thanks, everyone. I won't lose any sleep over it now.
  13. jeff_t

    jeff_t Minister of Fire

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    It'll wash off over the summer.
    ScotO and corey21 like this.
  14. billb3

    billb3 Minister of Fire

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    looks normal to me.

    smartphone pic ?
    my sister sends me pics taken with her iphone and I either have to view them sideways like she sends them or they go upside down, on an iPad.
    Wonderful technology. /sarc
  15. ScotO

    ScotO Guest

    perfectly normal, happens to mine from time to time.

    Now, when you have jet black, oily-looking streaks running down the OUTSIDE of your chimney 6' to 8', you have an issue.....wet wood!!
    It's never happened to me but I know of a few flues in my area that are like that ALL WINTER LONG.
    Backwoods Savage likes this.
  16. topoftheriver

    topoftheriver Member

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    nothing to be concerned about. sleep tight!
  17. formula_pilot

    formula_pilot Member

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    FYI, the Excel Class A chimney in my workshop is a new install, just 5 weeks old, and also now has a "rainbow" heat effected zone at the top, mostly on side leeward of the prevailing wind direction.
  18. topoftheriver

    topoftheriver Member

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    Maybe it is the result of a differential in cooling. One side is hotter than the other causing the metal cool faste/slower and cause the rainbow effect because of a type of molecular movement in the material. There has to be literature about it somewhere online. In short, I don't think you'll need a metalurgist.
  19. begreen

    begreen Mooderator Staff Member

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    I want to know why the cap is so black? Our cap after 6 yrs is still shiny. Are you burning poorly seasoned wood? When was the chimney last cleaned?
  20. nate379

    nate379 Guest

    Looks fine to me. Mine is black as well as the foot or so of pipe under it. Wood is 2-3 years old, dry enough I can light a fire with a match.
  21. begreen

    begreen Mooderator Staff Member

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    Seems a little dark for only 6 weeks of burning, but maybe ok?
  22. NortheastAl

    NortheastAl Minister of Fire

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    In the first week I had burned wood that I bought from a supplier that was supposed to be "seasoned" wood. As I learned from this forum, and by burning it, it was not well seasoned at all. It hissed and you could see water at the ends of the splits. I had then gotten kiln dried and some 18-24 month seasoned from another supplier. The cap did have the wet sticky look after burning the first week of that poorly seasoned wood. I had used the Rutland Creosote Remover capsules to help mitigate the effects of that lousy wood. The kiln dried and truly seasoned wood is burning clean. The sticky residue on the cap is more of a flat black now.

    As far as wood is concerned, the kiln dried burns the cleanest,but very fast and hot. In fact, too fast. The very seasoned wood burns slower and clean. Much easier to regulate the burn too. The first load that was not really seasoned I stacked and am drying for another year the kiln dried and well seasoned I mix or burn separately, considering how hot a burn or if I want an overnight burn.

    You guys had taught me a lot in a very short time. Still plenty to learn, though.
  23. NortheastAl

    NortheastAl Minister of Fire

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    I looked aout the front door and my man furnace chimney is sitting on the ground. It blew off last night or early this morning in the wind. The cap on the chimney for the stove got cleaned by the rain and driving wind. The center ring on the cap is now shiny again. Don't know if you can see it in the pic or not.

    It has dropped 10 degrees in three hours here. Still a 20 mph wind with higher gusts. Going to be a great night for burning.

    View attachment 91612 View attachment 91613

    Attached Files:

  24. begreen

    begreen Mooderator Staff Member

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    Ah, that makes sense. It's lucky that you could find some decent wood.

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