Galvanic Corrosion

coupling SS to GS can give galvanic corrosion. If only the screw, SS, is exposed to the atmosphere, rain, while the GS-SS interface will not be exposed to water or atmosphere then galvanic corrosio is not a concern.

here you can find information on galvanic corrosion og GS

http://www.galvanizeit.org/aga/designing-fabricating/design-considerations/dissimilar-metals-in-contact

if you want to be sure you can use a isolating washer between the two materials

S

corrosion prevention & corrosion protection

Thanks for your help. I will consider a threadlocker such as loctite, just to be sure of isolating the two metals, and to make the connection stronger.

Robert

You mention that SS nuts are not available.

This is a surprise.

Here in Australia, there is no trouble getting SS nuts for the common sizes of bolt.

I'm sure if you checked other countries you would have no trouble getting SS nuts at a reasonable price.

Use that and your galvanic corrosion problem between nut and bolt vanishes.

Thank you Sceptic. Problem is the nut is a "tee nut" with a 7/8" long shaft. It is a bit unusual, but further problem is that it gets another screw inserted in it from the other end. That screw is zinc plate and it attaches other pieces that are also zinc plate. Could change the original stainless screw to zinc, but it is also unusual shape and is exposed to weather if I could even find in zinc plate.

Robert

Thanks. That clarifies the problem.

In that case, loctite is probably your best solution.

Good luck