Changing color of class A chimney

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?

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

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...

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.

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

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

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

Normal . . . but just in case . . . look around for the leprechaun's stash of gold.

Looks fine to me.

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.

Sleep tight tonight. All is well.

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

It'll wash off over the summer.

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

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.

nothing to be concerned about. sleep tight!

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.

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.

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.

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.

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.

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