• Please visit and share your knowledge at our sister communities:
  • If you have not, please join our official Homebrewing Facebook Group!

    Homebrewing Facebook Group

Rust Spots on S.S. HERMS Coil

Homebrew Talk

Help Support Homebrew Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

DNelson

Well-Known Member
Joined
Feb 2, 2015
Messages
57
Reaction score
4
Is it normal for my stainless herms coil to be covered in rust spots? I haven't used any steel wool or anything that would imbed into the stainless. I had noticed the imperfections on the coil after receiving it, but they have all rusted now after one test run with water.

IMG_20170730_180332.jpg


IMG_20170730_180354.jpg
 
Scrub with a paste of Barkeepers Friend to passivate the stainless steel, let dry and run another water test.
 
Scrub with a paste of Barkeepers Friend to passivate the stainless steel, let dry and run another water test.

I plan on giving that a shot, but I guess my main concern is that I received a faulty product. The blue heat marks and the imperfections surprised me. My first thought was that the coil looks like it sat around a machine shop getting blasted with hot steel from a chop saw or something. I haven't seen a stainless coil before this so just wondering if they usually come with heat marks and metal chunks that you can feel imbedded in the surface, or not
 
Is your element which you have in the herms-container of the same material as the coil?

Try soaking it in dilluted citric acid for an hour.

Those spots seems "mysterious". But they are still on the other side of the steel where your wort flows..
 
I bet the coil was contaminated by steel wheels in the bending jig.
That'd be preferable to having the rust be due to lousy tubing.

I agree with giving BKF a go, but I'd make a paste of it then use a stiff scrub brush to work it along the full surfaces of the coil...

Cheers!
 
The stiffest scrubber I use with Barkeepers Friend is a damp paper towel. i don't want to make any new scratches.
 
A brush isn't going to scratch anything, and BKF isn't particularly abrasive to begin with (it's not Ajax or Comet).
The OP is going to need to get deep inside the "gaps" between the tubes.
I doubt a paper towel or cloth will be as effective...

Cheers!
 
It would be interesting to see if the same thing is going on the inside of the tubing. If the imperfections are heat related, and the tubing being thin, I would be more concerned if the rust/corrosion has permeated inwards or forming on the backside of these blueish marks?
Not sure if the rust spots are close enough to an end whereby you could shine a light in there or cut off a small sample (shorten the coil) for inspection?
 
A brush isn't going to scratch anything, and BKF isn't particularly abrasive to begin with (it's not Ajax or Comet).
The OP is going to need to get deep inside the "gaps" between the tubes.
I doubt a paper towel or cloth will be as effective...

Cheers!
Well it is abrasive .. just a finer abrasive than comet... thats why ss has the warning about it removing etching.. its closer to a polish in particle size.

That said I totally agree here that there is no concerns using it with a brush, cloth or sponge as I often do myself...
 
It would be interesting to see if the same thing is going on the inside of the tubing...Not sure if the rust spots are close enough to an end whereby you could shine a light in there or cut off a small sample (shorten the coil) for inspection?

Interesting point. I don't think there's anything near the openings but I'll take a look tonight. There's only 3 inches or so of tubing before it bends down toward the coil (comes out and over the pot like a standard immersion chiller), so I'm not able to look very far into it.
 
Hard to tell with certainty. To me it looks like it is welded tubing. And the corrosion is along the weld seam. Side not I would bet the corrosion will be inside and out.
 
Back
Top