Early Land Rover bodies were a mixture of steel and aluminium, if they ever got road salt on them they corroded really badly. I know this from experience of restoring a 1950 series 1 model years ago.

I suppose it depends on the surrounding environment as to whether you will encounter any problems, if it is parts for a clock, I would say you should be OK. I quite often mix aluminium and steel for making fixtures etc, and have not had any noticeable corrosion problems in the workshop.

Phil

Depedning on application is it possible to put a barrier between them?

Astom Martin used to use aluminium skins rolled and folded onto a steel tub chassis, wherever steel and aluminium touch, they use a cotton cloth soaked in what appears to be something like Waxoyl or Anchor wax, wrapped around the edge, and then the aluminium is clenched onto the steel like the edges of a door skin. Something like Sylglass tape would also work, if you can still get it. Steel bolts into aluminium can be treated with waxoyl, Densogrease or the silver version of Coppaslip grease, which is not, as far as I can remember called Allyslip! The whole purpose of seperating dissimilar metals in this way is to stop the ingress of water, which becomes an electrolyte between the dissimilar metals, and thus creates a battery, with the resultant electrolytic corrosion. Regardless of the materials, if they are dissimilar, a moisture resistant barrier will minimise the problem. It is like putting vaseline on battery terminals!

Phil

clean and oil the table before you fit it= no problem!

Edited By Phil Whitley on 28/12/2019 18:52:43

Where significant areas of both materials are concerned, shucha s car bodies on steel frames, proper practice its to electrically insulate any areas of contact.

Realistically mutual corrosion only occurs when things get damp or wet to provide an electrolyte.

Clive

A company I worked for built high tech transit containers for space and military hardware. The container build was all aluminium with steel/stl stl fittings and fasteners all of which were coated with Duralac on assembly.

Duralac prevents corrosion between dissimilar metals and is impressive stuff I have seen steel parts removed from aluminium ones where the item has lived out in all weather's for 20 years and the mating surfaces looked like new.

I don't think it needed in your case though Chris.

Even moisture and salt is fine if there is lot of surface of the anode (aluminium) and little surface of the cathode (stainless). Some tiny damage distributed over a large surface has no practical impact.

More to it than 'jobs were moisture is prevalent' I'm afraid. On an oily lathe, I wouldn't worry about mixing stainless steels and Aluminium because it's not a critical application. But the same combination is absolutely unacceptable on an aircraft exposed to weather and salt because the risk and impact of a failure are far higher.

Whilst breakage of safety critical parts due to corrosion is a risk most Model Engineers don't need to fret about, clock-makers and builders of fine models have another worry. A display item like a clock will be exposed to decades of air pollution, temperature swings and humidity. Careless mixing of materials is best avoided in these circumstances because small-scale corrosion is disfiguring. We don't want some as yet unborn expert tut-tutting over a beautifully made Chris TickTock Clock spoiled because a poor combination of materials reacted chemically over the previous century. Even though we'll all be dead.

Happy New Year everyone!

Dave