What metal is best for making car emblems that has a weather proof chrome like shine when polished?

The best material often depends on the process used to build the item.

For casting, I'll mention Zinc or Zamak. Either is easy to melt, and it's fairly simple to electro plate for a chrome-like finish. It's what most chromed Water Faucets are made of. Really, it's what most castings are made of.

For machining, it might still be Zinc, but as I've never machined Zinc, aluminum should be mentioned. Anodize for finish. Although, I'd not ask a shop to anodize just one part. Too much trouble. You could always use polishing compounds, but the finish would be temporary.

It might be possible to polish a part and then seal it using some sort of plastic spray. Again, I've never seen that done.

As Dang said, Zinc alloys are commonly used in cast parts and then plated. They'd have to be plated as raw/polished zinc will never hold a mirror finish, they'll corrode or tarnish in a hurry.

All chrome parts are some sort of polished base metal, brass, bronze, steel, zinc etc that are then copper and/or nickel plated with a flash plate of chrome on top.

If you want a white colored metal, that you can polish to a bright finish without plating, a nickel based alloy would probably be best. Sometimes they're called German silver, white bronze.

AL and obviously Sterling polish up well too, but without protective coatings, they'll tarnish right away so the finish will only last as long as the coating or as long as you want to repolish.

What I'm trying to do is machine a car emblem. I want to make it so that the polished finish never tarnish like the emblems you see on cars today.

but from the responses above, my understanding is that polished metal will never have a maintenance free shine?

Is chrome the only way to go for a maintenance free shine?

Thanks for the help!

Look into Caswell Platings site. They have casting kits, brush plating kits, conventional plating kits, anodizing and a slew of other items that are in the area of what you are looking for. They have a forum also that you can look through and see results of the different products they offer. I think the site is www.caswellplating.com you may have to google it though. I have bought alot of polishing supplys from them and they are a top notch company to deal with IMOP.

..... my understanding is that polished metal will never have a maintenance free shine?

Is chrome the only way to go for a maintenance free shine?

Thanks for the help!

Chrome or nickel plate are probably the best, but a lot depends on how the surface has been prepared and whether a good under-plate of copper is put on before chroming to prevent the unerlying steel or zinc based alloy from corroding. All plating tends to be porous and many times what you characterizes as tarnish is corrosion of the base metal causing pits in the chrome. The problem is getting good plating on one offs or small volume can be expensive.

Clear anodize over polished aluminum can be very close to chrome in appearance and it is possible to hand polish aluminum to a mirror finish using fairly simple equipment. If you have access to a good anodizing shop, or if you want to experiment with anodizing yourself this could be the way to go.

If you use 300 series stainless, it'll buff out to chrome and never rust for you. Not the best pic from my camera but you get the idea. It will match chrome when buffed out -