How can a Stainless Steel cap rust?

How can a Stainless Steel cap rust?

PostBy: jrn8265 On: Fri Apr 12, 2013 6:41 am

Well, I am confused, this is a stainless steel cap about 7 years old. Heo can it rust? I thought stainless does not rust? Appreciate your thoughts.
Attachments
oldcap.jpg
(182.4 KiB) Viewed 35 times
View: New PagePopup • Select:BBCode
[nepathumb]41647[/nepathumb]
jrn8265
 
Stove/Furnace Make: Keystoker Koker
Stove/Furnace Model: Koker 160

Re: How can a Stainless Steel cap rust?

PostBy: freetown fred On: Fri Apr 12, 2013 6:50 am

It's all God stuff--looks like most of it is around where your welds are.
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: How can a Stainless Steel cap rust?

PostBy: dcrane On: Fri Apr 12, 2013 7:38 am

Fred is right, sometimes when welding stainless the welder, grinder, etc. uses welding rod covered in impurities or the grinding disk was used on steel prior to grinding the stainless. but stainless steel can rust on its own (a better word might be corrode) because of electrolysis... this is why in the marine industry you should never see a stainless equipped boat also using bronze (older boats that use bronze need to stick with bronze and newer boats using stainless need to stick with stainless). In the case of coal burning and stainless these same hazards can happen and the coal gasses mixed with damp air can reek havoc on a stainless pipe (this is why most people here know how valuable a Terra cotta liner with a copper or stone cap really is). ;)
dcrane
 
Hand Fed Coal Stove: Crane 404


Re: How can a Stainless Steel cap rust?

PostBy: samhill On: Fri Apr 12, 2013 8:22 am

Just like with most things there are different grades of stainless & beyond that with the stuff we are importing now who knows what's really in it. As what was pointed out it is also the type of rod or wire used to weld but even if the wire was incorrect the weld would rust & fail but the rust wouldn't spread onto good grade stainless.
samhill
 
Hot Air Coal Stoker Furnace: keystoker 160
Hand Fed Coal Stove: hitzer 75 in garage
Stove/Furnace Make: keystoker/hitzer
Stove/Furnace Model: koker 160/ hitzer 75

Re: How can a Stainless Steel cap rust?

PostBy: jrn8265 On: Fri Apr 12, 2013 8:25 am

Thanks everyone. My new caps are 316ti so maybe they will have better luck!

Really wish I could just go with the terra cotta but it is cracked....

Love burning coal but man can it chew up things!
jrn8265
 
Stove/Furnace Make: Keystoker Koker
Stove/Furnace Model: Koker 160

Re: How can a Stainless Steel cap rust?

PostBy: SMITTY On: Fri Apr 12, 2013 8:30 am

You know the formula: Coal Ash + H2O = sulfuric acid. Stainless or not, no metal can withstand that kind of acid.

Stainless just slows the inevitable.

Masonry is the only solution.
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: How can a Stainless Steel cap rust?

PostBy: Dennis On: Fri Apr 12, 2013 8:33 am

jrn8265 wrote:Thanks everyone. My new caps are 316ti so maybe they will have better luck!

Really wish I could just go with the terra cotta but it is cracked....

Love burning coal but man can it chew up things!

can you post a pic of the cracks. Are they on the top or all the way down thru the chimney
Dennis
 
Hand Fed Coal Boiler: AHS/WOC55-multi-fuel/wood,oil,coal
Coal Size/Type: Anthracite/stove size

Re: How can a Stainless Steel cap rust?

PostBy: jrn8265 On: Fri Apr 12, 2013 9:06 am

in the middle of the chimney so no pics!
jrn8265
 
Stove/Furnace Make: Keystoker Koker
Stove/Furnace Model: Koker 160

Re: How can a Stainless Steel cap rust?

PostBy: freetown fred On: Fri Apr 12, 2013 9:44 am

If it's an external chimney, I would not worry about "cracks" in the middle.--or anywhere for that matter
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: How can a Stainless Steel cap rust?

PostBy: dcrane On: Fri Apr 12, 2013 10:04 am

freetown fred wrote:If it's an external chimney, I would not worry about "cracks" in the middle.--or anywhere for that matter


Im with Fred on this one ;)
dcrane
 
Hand Fed Coal Stove: Crane 404

Re: How can a Stainless Steel cap rust?

PostBy: nortcan On: Fri Apr 12, 2013 10:08 am

stainless can easily rust when in contact with aggressive products like acids, chlorine...
Since I began burning ant I look for some neutralizing solutions. Making a good black smoke wood fire coats all parts with a non corrosive film (wood stoves chimneys don't get rusted...) that ""limit"" a little the corrosive effect. One fire before the burning season and one at the end after the cleaning job.
Yesterday I tried something different. I ""fume the chimney with baking soda. The white soda fume was visible at the cap. Using a portable small sand blaster, the soda went all the way to the chimney's cap. I will make an other shooting on a rainy damp day. That takes about 5 minutes to do so.
Attachments
003.JPG
(104.21 KiB) Viewed 8 times
View: New PagePopup • Select:BBCode
[nepathumb]41651[/nepathumb]
010.JPG
(118.28 KiB) Viewed 11 times
View: New PagePopup • Select:BBCode
[nepathumb]41652[/nepathumb]
nortcan
 
Stove/Furnace Make: Stuart,Peterson/ Grander
Stove/Furnace Model: Sunnyside/ Golden Bride

Re: How can a Stainless Steel cap rust?

PostBy: freetown fred On: Fri Apr 12, 2013 10:15 am

Nice Pierre :) I was wonderin what you did on your off time. :nana: toothy
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
Coal Size/Type: BLASCHAK Nut/Stove mix

Re: How can a Stainless Steel cap rust?

PostBy: nortcan On: Fri Apr 12, 2013 10:21 am

freetown fred wrote:Nice Pierre :) I was wonderin what you did on your off time. :nana: toothy


Salut fred,
:D :lol I fume and play with pot :) oops, I mean fire pot liners.
nortcan
 
Stove/Furnace Make: Stuart,Peterson/ Grander
Stove/Furnace Model: Sunnyside/ Golden Bride

Re: How can a Stainless Steel cap rust?

PostBy: carlherrnstein On: Fri Apr 12, 2013 11:12 am

Stainless gets a thin film of chromium oxide on the surface of it and that seals it up so it wont rust, but acids can strip that coating off. Ther isnt a lot of oxygen in a flue thats being used so the coating isnt replaced.
carlherrnstein
 
Hot Air Coal Stoker Stove: combustioneer model 77B
Coal Size/Type: pea stoker/Ohio bituminous

Re: How can a Stainless Steel cap rust?

PostBy: steamup On: Fri Apr 12, 2013 11:32 am

I once worked for a mechanical contractor and we installed some stainless steel plumbing fixtures in a ball park restroom. They started to rust before the job was finished. The manufacturer told us to clean them with cleanser and the problem would go away.

Whatever they used in the manufacturering reacted with the stainless to cause the problem.

We used barkeepers friend:
http://www.barkeepersfriend.com/using-b ... ers-friend

There are various grades of stainless and some corrode more easily that others.

The right chemical will still attack stainless and cause problems. Sulfur is one of those chemicals. Cleaning will not prevent the rust but will slow it down.
steamup
 
Stoker Coal Boiler: Axeman-Anderson AA-130, Keystoker K-6
Hand Fed Coal Boiler: HS Tarm 502 Wood/Coal/Oil
Coal Size/Type: pea, buck, rice