Where the
world gathers for metal finishing
Q&As since 1989


-----

Will Stainless steel sign lose reflectivity?

I have recently designed an outdoor sign which has a stainless steel back plate. I have meticulously ground the plate to have grinding marks which reflect the light in all different directions. My question is, will the stainless corrode or loose the reflective quality once it is outside in the elements? If so, how do I protect it? Is there a clear coat that will do the job?

Thanks.

Brian Slocum
designer - Bethlehem, Pennsylvania
2004

---

Whether it will rust and pit depends on the environment and the grade of stainless steel, but it will lose reflectivity. Ideally you could take it to a plating shop for a "flash" of chrome plating to prevent tarnishing. This is widely used on stainless trim on autos.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

I am an artist who works in stainless steel. I have placed stainless signs outdoors in the midwest. I recommend a coating of stainless steel cleaner and polish applied at installation and periodically thereafter,i.e. every 6 months to a year. This works well for me.

Marsha Lega
- Joliet, Illinois
2004

---

September 16, 2009

Hey Brian,
I would have your stainless electropolished as the last step before installation. If it is 304 (18/8) or 316, 316L stainless grades it will remain bright and reflective for years with nothing needed other than soap and water cleaning from time to time (no wax, polish, or abrasive cleaners necessary)
As an example, I have electropolished my 4" 304 s/s exhaust fittings, elbows, and inline mufflers, (no zinc's attached) on my boat. They are located in the non-sealed engine compartment bilge that always has about an inch or two of salt water in the bottom. This area is constantly bombarded by salt water, heat/cool cycles and oxygen (three main thing you need for corroding). They have been installed since early 2006. It is now late 2009 with absolutely NO signs of discoloration, pitting, rusting, staining, loss of brightness, corrosion or failure.

Cliff Kusch
electropolishing shop - North Vancouver, British Columbia, Canada