Cap rusting out

Post by **tcalo** » Fri. Jun. 02, 2023 2:49 pm

I live on Long Island. As you can guess being surrounded by water we have very humid weather. My old chimney system was made by Metal-Fab. The system seemed good, but the cap rusted out after several years. I had it replaced under warranty but it was a pita!!! When I moved I installed my stove and chimney from scratch. After some research I decided to go with a Selkirk system. Install was easy and build quality was a bit nicer than Metal-Fab. It’s been 2 years April 23’ since installing the chimney system. I just got around to cleaning my chimney and the cap is already destroyed. I usually only sweep my chimney once a year, after the burning season. I called Selkirk inquiring about the warranty. I was told it’s a lifetime warranty, but with a one time replacement. He explained all about coal gas condensing and becoming corrosive, something which I know very well! It’s the nature of the beast. He suggested cleaning the flue several times throughout the burning season. I don’t see that helping all that much. I’m just curious if others have issues with caps rusting out prematurely?

Post by **nut** » Fri. Jun. 02, 2023 3:24 pm

I had 2 Metalbestos chimneys disintegrate. On my current masonry chimney I went to a metal shop and had a heavy gauge stainless steel cap made. Gonzo. I run topless now.

Post by **tcalo** » Fri. Jun. 02, 2023 4:35 pm

Topless…as in no cap? My concern is rain and snow getting down the flue causing more damage.

Post by **nut** » Fri. Jun. 02, 2023 5:15 pm

I am not saying you should but I've been capless for years. If I were to put one on I'd build it out of brick and stone.

Post by **davidmcbeth3** » Fri. Jun. 02, 2023 5:44 pm

tcalo wrote: ↑Fri. Jun. 02, 2023 2:49 pm SNIP I called Selkirk inquiring about the warranty. I was told it’s a lifetime warranty, but with a one time replacement.

What does the warranty actually SAY..not their interpretation of it

Post by **warminmn** » Fri. Jun. 02, 2023 5:52 pm

Its wetness, humidity on the ash that will rot it in your chimney. I doubt sweeping it daily would even help. Do one or more of the various things people do in the off season to help prevent rust will help some.

Post by **tcalo** » Fri. Jun. 02, 2023 7:42 pm

I wonder if painting it would help?

Post by **davidmcbeth3** » Sat. Jun. 03, 2023 1:05 am

tcalo wrote: ↑Fri. Jun. 02, 2023 7:42 pm I wonder if painting it would help?

Yes, it would. The best would be a UV urethane white or possibly aluminum containing paint (for light reflection as UV rays is a concern.

Preparation of the surface would be integral to the success. A primer is recommended.

Post by **waytomany?s** » Sat. Jun. 03, 2023 7:34 am

Do your building codes require fasteners for corrosion resistance?

Post by **lzaharis** » Sat. Jul. 01, 2023 9:58 am

Metal chimneys will rot out just as stainless steel
chimney extensions with caps will.

My 9 year old stainless steel chimney extension with
rain cap and spark arrestor screen was attached to
the concrete chimney cap my uncle put on the chimney
for me almost 24 years ago.

The stainless steel chimney extension I purchased from
Rockford Chimney Supply 9+ years ago came with a
mounting flange that was attached to the concrete
chimney cap with tek screws.

The base of the stainless steel chimney extension began
to rust 2 years ago and after the 2022-2023 heating season
was over it was so weakened from heating the home with
coal by it was blown over in the last windstorm we had and
broke away from the hinge that allowed it to be tipped over
and the chimney cleaned if you burned wood etc.

Any method of heating will destroy a metal chimney cap or
chimney extension by the way.

A clay chimney pot/extension is rot proof but requires a cinder
block tile lined chimney or brick tile lined chimney.

I am not sure if you can purchase an ashphalt based paint anymore.

I have an old vacuustack with wire mesh to prevent birds from nesting in it to put in
place of the chimney extension this year

Post by **SMITTY** » Sun. Aug. 27, 2023 3:40 pm

Best thing to do is find a better quality stainless cap. 316Ti is the way to go there. Might have to pay out the ass for it, especially if it has to be custom made, but at least it would last.

I've got a 5" stainless chimney & cap for my waste oil burner. I get some pretty corrosive chemicals mixed in with the oil occasionally, and it destroys the galvanized sections within months of sitting idle. The cap and pipe are still good. The vertical pipe came with the house - was on an oil burner in a greenhouse. Wish I knew where the previous owner got it, because that size is IMPOSSIBLE to find today in a single wall configuration. It's lasted all these years being outside. Was uncapped for decades. Probably can't buy quality like that today anymore anyway. Sad sign of the times.

Here's 4 months on a galvy pipe. As soon as I laid a finger on it, it disintegrated:

IMG_9642.jpeg

IMG_9643.jpeg

IMG_2547.jpeg

Post by **mntbugy** » Sun. Aug. 27, 2023 5:59 pm

Just replaced the SS chimney cap again. Also a new chimney pipe adapter. It lasted 14 years. Caps only last 3 seasons at most. Burning 9 months out of a year.