The authoritative public forum
  for Metal Finishing since 1989
-----

White film inside stainless steel tubing:

I have received some tubing from Germany that was rejected because of white residue inside tubing. The finish is R16 that has passed inspection. Any idea as to what this is and how can I get rid of it. Some of it will wipe off but there still is film that is attached to the inside wall. Any help will be fine.

Michael Crabtree
Cleaning and Passivation - Clayton, North Carolina, USA
November 18, 2010

---

Hi, Michael. Your situation is doubtless clear to you, but I apologize that I'm lost. You inspected this tubing, shipped it to Germany, and it has now come back to you with white residue? Or a German company provided it to you and you initially rejected it but now you want to salvage it? Is your tag line implying that the tubing was supposed to cleaned and passivated before it got to you, rather than by you? Is this heavy structural tubing or hypodermic needle tubing?

Sorry, but I'm just not familiar with what process would leave white residue inside tubing, or what you are talking about -- but is it possible that this is a buffing compound? Could whoever "finished" this tubing have buffed it and left some buffing compound on the inside? Is it only at the ends or uniformly distributed along the whole length of the tubing? Get back to us please.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 18, 2010