-- The Home Page of the Finishing Industry

on this site
current topics
Live! From beautiful Pine Beach New Jersey: Welcome to the world's most popular metal finishing website

topic 60534

Is rust contagious?

October 23, 2017

Q. Sorry for the salacious posting title.
I have a threaded assembly with a steel washer and a brass plated housing. The steel washer has rusted out and the threaded housing has rusted through right next to the washer but has no signs of rust anywhere else on the housing. So my question is, "Does the rusting of one part, cause rust on the other?"
I ask because I am hoping to fix the problem by simply changing the steel washer to a SS one to prevent the first part from rusting and thus protect the threaded housing.

Charlie Harland
- Kitchener, Canada

October 2017

A. Hi Charlie. Rust is not contagious. Rather, things that are very close together tend to rust similarly because the same environmental conditions prevail. Water probably accumulates in the gap between the threads and the washer. Put some thread sealant, or at least teflon tape, on the threads to discourage moisture accumulation and the situation should be somewhat improved.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

January 23, 2018

A. Once one area of the surface has become oxidized form of the metal, now this corroded portion of the metal will exist at lower potential relative to the bare metal. This variation in surface potential will drive galvanic corrosion in same mechanism that is caused by dissimilar metals. In effect, this can also be used to explain pitting. The pit is active metal and the perimeter is the protected oxide. Therefore, once corrosion products form non-uniformly across the surface, then you are in trouble and should try to remove it or cover it. Passivation of metals before application can form a homogeneous oxide layer and this layer not only becomes barrier, but it limits variations in surface potentials as well as conductivity thru electrolyte interface. In summary, corrosion/rust could be considered contagious because of the way it can spread.

William Rigdon
Stanley Black & Decker - Baltimore, Maryland

If you have a question in mind which seems off topic, please Search the Site

ADD a Q, A, or Comment on THIS topic START an UNRELATED topicView CURRENT HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2019, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.