stove pipe question

Coming off the back of my stove I have a 8" opening, I had on hand a very heavy gauge 10" galvanized stove pipe which I used for the 24" horizontal run. I overlapped the pipe and fastened it with sheet metal screws so it's now a 8" pipe with a 2" double wall section where I modified it. It fits nice at both ends. Now that it's all done I've been thinking about it; do you guys think the gas will be able to work it's way out through the seam? Should I seal it with furnace cement?

It definitly could leak, but so can most of the pipe joints and sectional elbows. If your chimney has a steady draft, then the pipe will be under a slight vacuum, and pull air from the room into the pipe.

The only time that the pipe may leak would be if it had positive pressure. Such as when the combustion blower first comes on and the chimney isn't pulling that strong yet, or if you had really gusty/windy weather and you had some flow reversals in the chimney.

Just to be safe I'd seal it, you can use good hi-Temp RTV gasket sealant or furnace cement. But don't neglect the other joints or the fitting going into the chimney if it is masonry. All can leak some under pressure.

You did use three or more screws in each slip joint for security right??

Greg L.

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Hi e.alleg 3M also makes HI- Temp Flue tape 1 1/2 in wide 15ft roll good for up to 600F silver but can be painted black with HI - temp stove paint A liitle pricey but much easier to put on then that stinky HI -temp sealer or furnace cement and will last for years just my two cent's Have fun