Making metal pickup rings

[MPU]

I’m planning to make Yamaha-esque metal pickup rings for PJ pickups. I’m making them from aluminium or stainless steel. Aluminium is easier to saw, drill and file but does not polish as well. Are there any tricks for either working with stainless or polishing aluminium? I know stainless hardens if heated when drilling. Or should I use German Silver?

 

[Beej]

Personally, I like German silver for the workability, ease of polishing, and also the final colour. It's less blue-white than either aluminum or stainless when polished IMHO. I think it looks the closest to chromed finishes of the three.

 

[T_Bone_TL]

Technically speaking, stainless work-hardens - it's not a heat thing. It's a "Don't take it easy while trying to cut" thing - if your drill or saw isn't throwing an honest chip then the surface will work-harden and your drill or saw will get dull really fast.

German silver/nickel silver is a big win on workability over stainless.

I usually go for a brushed finish on aluminum, though it's a great candidate for "engine turning" aka "jewelling" as a finish, if that would happen to work for the aesthetic you are going for (and there's no reason you couldn't do that to German silver, or stainless either.) Mirror polishing it I have no tricks for. Patiently work your way through abrasives removing all scratches from each previous grit...

 

[Bruce Johnson]

Hey Marko;

My Metalworking thread has been quiet for a few weeks, because I've been very busy on other things. I'm planning on getting back into it and starting the discussion of milling technique......But maybe I should hold off on that and talk about making metal plates for a page or two. That's metalwork that we Luthiers can do without the big machines. And it's not difficult.

Some quick answers: I agree with Beej and T_Bone. Aluminum is much easier to cut and shape and polish than stainless. Nickel-Silver is also easy to work with.

You can make the plates from stainless, but it's about 2X the labor hours. You have to cut and file slower, with more power, being careful not to build up the heat. But stainless can be drilled, sawn and filed with normal tools...with some patience and care.

Any of those metals can be sanded, polished and buffed up to a full "chrome-like" shine. Aluminum is pretty easy to buff up. It's a whiter color than chrome, but it looks very nice. You need to give it a protective coating afterward, a wax or a coat of clear polyurethane. They make special paints for coating polished aluminum.

About the same for Nickel-Silver. Polishes up easily, but will be a darker, more bluish color than chrome. You should coat it with a metal polish/wax to keep it from tarnishing.

Stainless is harder to polish up, more work, but it looks beautiful. A shade darker in color than chrome, but close. And it doesn't need any protective coating. It'll look good for many years. Almost a durable as chrome.

You can also make the plates from aluminum (cheap and fast), sand them to 1000 grit level, and send them out to be Show Chrome or Bright Nickel plated.

On my Scroll Basses, I make almost all of my plates and other hardware from 6061 aluminum. For my Walnut models, I do the Brush Finish, which is smooth, even sanding at 400 grit. That's the satin aluminum look. For my Classic models, I sand the aluminum to 1000 grit and have them Bright Nickel plated. But I do make some parts from 304 stainless and just polish them up to a chrome-like look.

 

[MPU]

I’m leaning towards aluminium and a bit tinted clearcoat. My aim is sort of black chrome like Yamaha has on their BB734 basses. I have found acrylic spray clear coat for tinting car rear lights and I’m giving it a try. Like Bruce said, aluminium is easy to work with and polish.

 

[Bruce Johnson]

I’m leaning towards aluminium and a bit tinted clearcoat. My aim is sort of black chrome like Yamaha has on their BB734 basses. I have found acrylic spray clear coat for tinting car rear lights and I’m giving it a try. Like Bruce said, aluminium is easy to work with and polish.

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Yeah, that's fine. I would sand the aluminum parts to 1000 grit level; taking out all scratches lower than 1000 grit. Wash them with a degreaser. Then paint them, trying to keep them free of dust and allowing the paint to flow out to a good gloss. You don't want to do any level sanding or buffing! With metal parts, you can also let them bake in the sun for a while, to harden the paint a bit more.