DAMAGE FROM USING FERRUS STEEL BRUSH ON STAINLESS PIPE

[WES999]

Here is something for further reading about stainless steel corrosion and passivation.
(broken link removed to http://www.iftworldwide.com/white_paper/passivation.pdf)

Being in the manufacturing business, we routinely send stainless steel parts out to be passivated, basely parts are dipped in acid to dissolve any iron left on the surface from machining.

I purchased a Rutland poly brush for my chimney, it is a bit on the small side, it dosn't fit as tight as I think it should.
Any one else have this problem? Is there a brand/model of brush that works well and fits snug but no too tight?

 

[JotulOwner]

I have to wonder if there are any other alternatives when it comes to brush materials. As far as I know, there is ferrus steel and there is plastic. How about another metal? Maybe even a thin stainless steel wire or other metal that can't cause corrosion damage to stainless steel?

I thought of brass brushes (before all of this technical talk made me realize that I have no idea what is good or bad) because it is a metal which might clean chimneys better than plastic, but is softer than steel so (I believe) it shouldn't cause much physical damage/wear to stainless. I use a BBQ brush to clean black stove pipe and it works very well. I'm not sure if it is brass, bronze or some other metal, but it doesn't look like steel. I was only concerned about scratching the stainless before I heard about possible corrosion. I suppose brass could be bad too. Who knows?

Too bad there aren't more mad scientist wood burners out there 8-/

 

[Corey]

My .02 (after dealing with all sorts of metal and metallurgical failures for 15+ years - and seeing some pretty wild "I never thought that would happen to stainless" failures)

1) Stainless is a pretty weird beast. First notice it says "stain-less" not "stain-proof" so we know certain things can attack it.

2) The thing which makes stainless, stain less is it builds up a relatively transparent, tightly adhering oxide coating. On normal iron, this is called rust. It is loose, red/orange and constantly flakes away exposing the underlying metal untill you have a hole.

3) Stainless steel 'needs' oxygen to stay stainless - it helps rebuild any damage to the oxide layer. Normal steel is just the opposite - exposure to oxygen causes rust to accelerate and worsens corrosion.

When you run a steel brush through a stainless liner, it is probable you will scrape some of this protective stainless oxide layer away. A hardened steel wire can most certainly scratch stainless - thus removing the oxide coating. Most likely, a bit of stainless steel metal will oxidize to replace the oxide layer and that will be the end of it - except you just converted a small amount of solid metal to metal oxide. It is also possible a particle of metal could settle on the freshly gouged stainless and start a corrosion pit as mentioned earlier in this thread. Though keep in mind, all this is happening on a microscopic scale, so you need many microscopic pits or scratches joining together to make an actual hole. This isn't something that will just happen overnight, but will build up slowly...just like rust in your car fender wells.

With all that being said - a metal brush in a stainless liner has the possibility to shorten the life of the liner. How much? It depends...maybe 5%, maybe 50% - depends on many operating and atmospheric conditions of that liner. You may not notice any difference at all (maybe you'll have to replace the liner at 18 years instead of 19) or it may cause an accelerated failure you'll have to deal with much sooner than expected. Conversely, a poly brush will absolutely, positively not affect the life of the liner in any negative sense . With all that being said, I can tell you which brush is in my garage - and it's not metal.

 

[Highbeam]

I purchased a Rutland poly brush for my chimney, it is a bit on the small side, it dosn't fit as tight as I think it should.
Any one else have this problem? Is there a brand/model of brush that works well and fits snug but no too tight?

Not sure if my poly brush is made by Rutland but I think it is. The vendor sells lots of other rutland. Anyway, mine is loose fitting in the class A but much tighter fitting in the double wall stovepipe. It is so loose in the class A that I actually side load the brush and work it well. The other reason that it could be loose fitting is that I hardly have any buildup so it doesn't have anything to brush.