Heres a little interesting short story for ya. I'm using a single wall 6 inch black stove pipe for a chimney until I can afford to install a double wall. I used 3 screws at each connection and the thought of sealing the connections didn't occur to me. Totally a newbie mistake I'm sure lol. SO, the first heavy rain we got I had stuff pouring out of the pipe in my basement, even though I was smart enough to put a cap on top. It leaked onto my cold air return boot and stunk up the house with soot oder from the punky pine wood I was burning, another newbie mistake. I concluder that the rain water was running down the side of the pipe, gathering at the connections and wicking thru the joint and running down the inside of the pipe, since the male end was pointing downward like it should.
This is were my brilliance shines lol. I thought ok, if I flip the pipe the male end will be pointing upward solving the problem of precipitation getting in the thru the pipe joints So my buddy came over, we flipped the pipe and I was smiling.
About two weeks go by, (I should mention that I was burning coal now) and I see gunk running out of the pipe joints. Another couple weeks pass and my whole pipe is looking really bad. I thought, oh man what I gonna do?? It turns out that condensation was forming on the inside of the pipe running down and carrying fly ash with it to the outside of the pipe. Another couple weeks pass and now I'm concerned that the mix of ash and wet is making a sulfuric acid substance and eating the pipe!! I checked a couple places on the pipe and noticed the pipe had been eaten down to the metal.
At this point I start to panic. Luckily the winter has been mild and I can still get on the roof. So I take the pipe down AGAIN, scrub all the funk off it and see that alot of paint has been eaten off it. Not much I can do about that part I guess other than blast some stove paint on it. I seal all the pipe joints with hi temp silicone and flip it again so that the male ends are pointing down again
Finally, my pipe is better now lol and I only have a tiny bit of gunk draining out of the bottom of the T outside since I installed the barometric damper. Hopefully I can get another year of two out of the single wall before I put up a permanent pipe
So the moral of the story is, don't flip the pipe, just seal the connections with hi temp silicone. This would have saved me a HUGE amount of effort. Live and learn, the trials and tribes of a newbie coal burner