Fireplace flue - unusual blob

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New Member
Jul 23, 2018
New Zealand

We've got an unusual blob formed on the external wall of the chimney flue. Just wondering if you have seen anything like that before and know what it could be? The flue kit has been installed new in Sept-Oct 2015

Haven't touched it yet, as don't want to damage the flue any further just at this stage, however, my guesses are:

1. Something stuck from outside - melted plastic or similar
2. Rust forming or burned out from inside
3. Pinhole leak and build up creosote

Here is a pic


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That is unusual. Could be a defect in the stove pipe. Contact the installer.

PS: is that wood on the stove top? Hopefully this is only when the stove is cold.
Looks to me like something scraped against the pipe scraping the paint up into a blob. Maybe someone lifting one of those wood splits?