DAMAGE FROM USING FERRUS STEEL BRUSH ON STAINLESS PIPE

I moved a response to a different topic by member "Berlin" to a new thread because this is very interesting and may not have been fully appreciated in the prior thread.

Berlin stated:
"the problem w/ metal brushes on stainless chimneys/liners flex or not IS real. It will damage the chimney, not as fast w/ wood as with fuel oil/coal due to less acidity, but it will cause a shorter lifespan nonetheless. Bits of steel become embedded in the protective oxide layer of the stainless which allows a pit to form like a cancer. some alloys are more resistant to this than others, 316ti being one, but damage is still being done. btw, it has nothing to do with actually “scraping” away at the liner itself, rather, as i mentioned, the embedding of non-stainless steels into the exterior of stainless steels allows corrosion to start on an otherwise healthy chimney thus giving it a shortened lifespan… and it ends up looking like swiss cheese. Coal is especially bad for stainless chimneys/liners because the flyash naturally contains bits of iron, as well as higher acidity etc. This is why Coal should not be used with stainless unless the user has the expectation that the liner/chimney won’t last more than a decade, and likely not even that. There is a very good thread (on the Nepa coal website) on a stainless flex 316ti (the MOST corrosion resistant alloy) being used with coal; it collapsed after less than 5 years and looked like a slinky. That is what happens when iron particles allow pinholes to begin on “stainless” steels in a corrosive environment. "

At first, I thought, well, maybe, opinions are like a@#holes (borrowed from Clint Eastwood). But, then I did some reading and found this:

"Contact Corrosion
This combines elements of pitting, crevice and galvanic corrosion, and occurs where small particles of
foreign matter, in particular carbon steel, are left on a stainless steel surface. The attack starts as a
galvanic cell - the particle of foreign matter is anodic and hence likely to be quickly corroded away, but
in severe cases a pit may also form in the stainless steel, and pitting corrosion can continue from this
point."

Before cleaning my stainless chimney I inquired about whether to use a poly or steel brush. There were various opinions in this forum, but I also asked Selkirk Metalbestos since they made the pipe I own. They didn't have a problem with me using steel wire.

I tried both. I think that the steel cleans better, but I only used it on occasion when I thought plastic didn't do the job.

I guess I will be contacting Selkirk again to see what they have to say about this. Fortunately, I did keep a copy of their response to my original question, so my warranty should be in tact.

I can't be sure if this really is a problem for wood burners, but it is certainly is worthy of further discussion. If anyone has SS pipe cleaned with a metal brush over a long period of time, please comment.

Once again, I have to thank every member on this site who takes the time to share their information and opinions.

ever left a cast iron pan in a stainless sink? I have... and it leaves a nasty rust stain.....I buy into the OP's comments.

Just use a poly brush, do you really need a squeaky clean fluepipe?

Yeah, but the horse is already out of the barn (too late to close the door) :coolsmirk:

Wunder if coating of used oil in staneless chimly at end of seeson wood slow decay and inhibit stiking of head whilst gandering for cheese?

Dang! Looks like I lit a fire too early and not even in my stove :lol:

head cheese and eye pudding are best served on a chilled silver platter!

Head cheese is best eatin' with a fork 4 U 2

I feel like I am in Bizzaro world watching Pook argue with his alter ego.................

JotulOwner, good post.

I've posted before about talking to installers. They recommended the poly brush for the SS chimney. Stated that the only SS chimneys that they have seen go bad are ones that were cleaned with a wire brush.

Because the brush costs so little, I bought a poly and the steel wire brush sits in the barn...rusting. If $15 makes the chimney last longer, I see no problem. If not spending $15 makes it an iffy situation.....

Regardless which brush works better, it certainly is not worth arguing over as has been done in the past.

I have a Hart & Cooley Class A system. I noticed on the tech talk section of their site, they recommend that after you do the final cleaning at the end of the season that you spray WD40 on a rag, wrap it around the brush, and run the rag through the Class A to give the inside a light coating to help resist corrosion.

Great idea!

didn't no U wer calf lik !
that splains the cheese and pudding!

I appreciate that something i said was found to be interesting

btw, to view what happens to stainless pipe that's been pitted from iron embedding on the surface via coal flyash in a corrosive environment, check out this link : http://nepacrossroads.com/about11423.html

Thanks Dennis

I'm not sure how much damage I did to my chimney by using a steel brush. I just want others to know before they do the same.

Makes sense to me...thanks for the post.

I couldn't put the plastic brush through my pipe.
I thought it would be a drag if it got stuck.
Maybe they make them different now.
The wire brush works fine.

Your comparing supposed iron content in fly ash along with sulfur & other nasties, to wood burning. How much iron content is in wood burning exhaust gases?
I noticed your the only one who mentioned iron in all those posts. Yes I ready all 3 pages worth. Thank you, was very informative. But your the only one to blame supposed iron in the flyash.
And not one person even acknowledged your statement. So, just because Berlin says so, that is the way it is?
I'm 3 years in with cleaning with a steel brush, I'll let ya know how it goes.

Of course on the internet, anyone can find some info to support their theory, but here is direct from Wikipedia;
"Depending upon the source and makeup of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) (both amorphous and crystalline) and calcium oxide (CaO), both being endemic ingredients in many coal bearing rock strata."
I could not find anything about iron, iron ore, or steel in there anywhere. Just curious, but would be interested in reading any helpful info you could supply?
Thanks

I can see that you like cleaning your chimney with a steel brush, and that's fine; it's your chimney and the damage won't necessarily happen quickly, and i may not happen for the life of your stove/chimney. I was NOT comparing burning wood w/ burning coal; what i WAS doing was illustrating what the iron in coal combined with a MORE corrosive chimney environment than a woodstove chimney will cause in a much quicker fashion thus giving you an idea of what COULD be occuring in a woodstove chimney when using a metal brush, albeit over a much LONGER period of time. I don't really care if i was "acknowledged" or not in post about iron particles causing damage; I post information that might be to someone's benefit. If you want to investigate to find out whether or not i'm full of chit, well, by all means go ahead. Coal DOES contain iron in the ash, in some cases a lot of it, i'm sorry the article you read did not inform you of that. In an appliance like a coal stoker furnace where flyash is generated (not the same as flyash from industrial boilers btw) ash containing iron will deposit itself along the flue lining along with corrosive and potentially corrosive minerals/chemicals (chlorine, sulfur oxides etc.) I'm not sure of whether or not others in that thread were aware of this or what causes stainless steel pitting/corrosion; I AM, and thus i posted what i know.

"So, just because Berlin says so, that is the way it is?" yes. :coolsmile:

apparently you didn't read far enough

DIRECT FROM WIKIPEDIA:
Fly ash material solidifies while suspended in the exhaust gases and is collected by electrostatic precipitators or filter bags. Since the particles solidify while suspended in the exhaust gases, fly ash particles are generally spherical in shape and range in size from 0.5 µm to 100 µm. They consist mostly of silicon dioxide (SiO2), which is present in two forms: amorphous, which is rounded and smooth, and crystalline, which is sharp, pointed and hazardous; aluminium oxide (Al2O3) AND IRON OXIDE(Fe2O3). Fly ashes are generally highly heterogeneous, consisting of a mixture of glassy particles with various identifiable crystalline phases such as quartz, mullite, and VARIOUS IRON OXIDES.



.

Well done, thats the information I was curious to read/learn.
I should have read further, your correct.

I've seen rapid galvanic corrosion between copper and steel, and seen rust on SS, but I'd be surprised if the small amount of iron deposited by a brush resulted in much ss pitting, unless in a very damp environment. Coastal areas, burning wet wood might take some time off the lifespan of a ss chimney, but how much? I brush once a year, so I'm not too worried. If I see a great deal on a poly brush I might switch, but it seems like a minor risk to me.