Rusty Galvanized Stove Pipe.

In the summer my galvanized stove pipe rusts on the outside. It starts out as small white bumps than that turns into a rusty spot than starts to spread. Nothing else gets that way in the basement only the stove pipe.

Hello TikiGeorge,

It is most likely a case of a very thin galvanizing layer reacting
with the moisture in the basement. I am unsure if stove paint and
sanding would solve that.

No galvanized on solid fuel appliances according to the people that make stovepipe.

It's the acid left inside by the coal. Moisture combines with it to produce sulfuric acid.... not good... either keep replacing pipes every year or get stainless steel pipe.. they say it rots that too but I've had mine up for 10 yrs now and still good... Got it at Lowes... inside is of a better quality then outside.. out side is still good as well. Especially at the top were the residue is the most.
I have a good cap on it that might keep rain out and the last few years have a light going all off season in the ash pan to keep moisture out of the stove and I bet the pipe gets the steady warm dry air as well.

Can't galvanized pipe actually be hazardous to your health? Replace with black pipe.

Galvanized metal lets off toxic fumes when heated.

Temperatures over 392 degrees will cause the zinc to seperate:

http://www.galvanizeit.org/hot-dip-galvanizing/how-long-does-hdg-last/in-extreme-temperatures

Sounds like poor quality pipe. Get some heavy duty black pipe and try to keep the basement humidity under control during the summer.

+1--everything I've ever read or heard recommends black pipe--NOT galvanized.

freetown fred wrote:+1--everything I've ever read or heard recommends black pipe--NOT galvanized.

Yup, absolutely, and some here found it helps to burn some "green wood" in the fall and then again in the spring if at all possible...plus, remove the black stove pipe at end of season and store it in barn or attic after a light brushing...putting it some where away from any condensing temperatures.

The burning of the "green wood" will lay down a creosote layer (a good thing) to help seal and protect the fly ash causing acids from attacking the iron.

Oh, Plug the thimble to seal off from natural chimney draft (up or down) and critters coming to visit ya .

Thanks for all of the replies!