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

How to stop rusting inside of tubes when electroplating

Our company has been trying for years to find a way to stop rust from forming on tubes. We operate a electroplating process, and the problem of rusting forms in the id of tubes. What I'm wondering is weather we should be treating the tube before the plating process," like we've been trying for a year now", or should we just clean & apply a different coating on the id of the tube. I was thinking maybe a Iron phosphate, a protective film, or even some type of paint. In any case this is why I need some problem solvers like yourselves helping me figure this out.

Thank You

Jeff Powell
- Aeroquip Corp.
1998

---

It is expensive and difficult to clean the inside of tubes, but unless you can afford to do this, you may be stuck. In the early 1980's, I visited a few plating shops in Brooklyn, New York who were using Nickel-Iron plating baths for plating clothing racks. It helped them because the Ni-Fe bath has iron complexing agents, and any iron and iron oxides which flushed out of the tubes were dissolved in the bath. They still used hexchrome plating, so the chromic acid got into the tubes and may help there. Design of the object being plated, I am sure, made sure that rust bleedout was minimized. I don't know if anyone uses nickel-iron plating anymore, but it is a nice, bright, ductile plate, and IT LEVELS LIKE PAINT, right Ken? (one time my old boss heard a sales engineer use this expression; he was not amused). I don't think plating levels quite like paint.

  
Tom Pullizzi
Falls Township, Pennsylvania
1997