dissimilar metal corrosion - bronze & galvanised

[lesweeks]

I've replaced the stem post on my restoration project and made up some Si Bronze studs to hold it in place. I want to spread the load a bit across the apron on the inside and,at the moment, I've got a mixture of 75mm dia brass discs about 3mm thick and some 50x50 galvanised plate washers doing the job. The brass is pretty hefty and I guess it'll last a fair while - especially if it's painted over - but once the holes are plugged and faired on the outside I won't (ever) want to undo the studs and so I think I'll replace them. Question is will bronze stud, washer & nut be OK with galvanised plate washers or do I have to dig deep and get some bronze ones made?

 

[peter radclyffe]

attach a wire to each end & see if it will power a light

 

[JasonClark]

Hi, Your Friendly " Engineer"
Here. (aimed at one person in particular.... BTW)


Bronze is an alloy that contains copper, and so the two metals are non-reactive to one another. Neither will cause the other to corrode. in your first instance.

When mounting bronze/brass/copper to galvanized metal/steel, bronze/brass/copper will promote corrosion of the steel with the metal salt it emits, while the brass/copper attached to it will remain free from corrosion.

Hope this Helps.

Jason.

 

[Seanick]

3mm washers a bit thin. Try two under each nut. Miss out the galvy washers. Don't overtighten and distort the washers. If they do distort, then get some brassy/bronze ones cast up-probably cheaper and easyer than cutting from plate.