wiping contact on aluminum

Sliding contacts on aluminium will always fail. Sliding *anything* on aluminium is bound to fail. Either attach a pad of CuBe or some other Cu alloy to one side and have your moving contact slide on that, or perhaps attach a piece of thin piano wire between the moving parts in such a way that it never exceeds its elastic limit.

Jeroen Belleman

A phosphor-bronze spring leaf in tension against a copper or stainless steel (resistance is not a concern) rail might work. Self-cleaning only works if the wear (cleaning) is able to keep up with the growth of oxides, so environment and how often the places are wiped count too.

For short distances something like a spring loaded cable in constant contact might work. (think: tape measure)

Conductive plastic strips...

An iridite or alodine coating on Al leaves it conducting, but I don't know how long it would stand up to rubbing/ switching.

George H.

Never slide two ident materials on another. One side must be harder, one side softer.

w.

Aluminum oxide is hard, and makes a good abrasive. That's not good for sliding aluminum-on-aluminum. Copper is troublesome, because it enhances aluminum corrosion. You can clean and abrade, then apply aluminum solder (a zinc alloy) which in turn will solder-join to many alloys. Rivets also might work (but interfere with the structure). If it's only for static, you might get away with a galvanized chain (also amenable to the same zinc-alloy solder).

Or, you could weld a boss onto the structure, with a tapped hole, and (using suitable paste) make a bolt-on electrical joint

Way back in the ancient past almost all cars had grounding straps. The tires were insulators, and the friction of autos moving through air would cause static charges to build on the surface of the auto. (at least that was the theory) The first passenger to step out of the vehicle would be the one to discharge the static, and get shocked.

I seem to remember that you could get a pretty painful shock just touching cars that were parked occasionally.

I seldom see a grounding strap so I assume they put some compound in the rubber of the tire to bleed off static? I notice on my wife's old Toyota I'd get shocked (only on dry days) when I touched the outside of the car, but that may have been from sliding on the seat when getting out.

I *always* go out of my car with my hand touching the metal first and then putting foot on the ground.

Pere

It won't take much voltage to punch through the natural aluminum oxide layer, or even deliberate anodize. Discharging static doesn't need a connection that measures low resistance on an ohmmeter.

You could press a grounded sealed stainless-steel ball bearing against the moving structure; that would last for many years.

There are also conductive brushes, like the ones used in copy machines.