Mirror finish on metal

Old 09-25-04, 09:10 AM
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Cool Mirror finish on metal

I have recently taken on a side business of refinishing turntables. On the top of the turntable is a flat piece of metal (plinth). I have asked many different people how to do this and I have spent about $300 on various ways trying to put a mirror finish or nice polish on it. Some of the different ways I have tried is by buying a $80 kit that works with a 4.5" angle grinder then to smooth sand paper ending with a white rouge. I have started with a DA sander all the way to polishing. The closest that I can get is by using a Sisal buff with Emery and ending with a final buff with white rouge. This last way works really well for small areas but the size of the metal I'm working with shows to many differentiating spots, some more polished and vise versa. I have finally decided that even if the metal just looks like metal, it will work. Yesterday I bought primer, chrome, and clear coat spray paint. This worked and looks good, but not the results I'm looking for, I want it to look like metal. I would like to sell these metal plinths for right under $100 and would really appreciate if someone could help me find a way to make these plinths look good without spending a lot of money.
Old 09-25-04, 05:58 PM
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I assume by your user name that you mean audio turntable.

What exactly is the composition of the metal?
Is it the original, what I used to call the platter or plinth?

The degree of polish has a lot to do with the composition of the metal.
If the piece is a cast material of some type, which most turntables are I believe, you may never get the shine you are trying for.

If this is an audio turntable, what make and model are you dealing with?
Old 09-26-04, 10:27 AM
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AR Audio Plinth

This is an early Acoustic Research plinth. Not cast metal. Not exactly sure what type of metal. But I do know that it is magnetic. I would appreciate any more help. HOW DO I GET IT TO AN EVEN SHINE?
Old 09-26-04, 11:03 AM
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How about engine turning? If you're not familiar with it look at the front of The Spirit of St. Louis. Not hard to do with careful layout and a drill.
(I thought a plinth was the disk that a crucible sits on in a foundry?)
Old 10-07-04, 08:56 PM
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Just guessing but it sounds like your RPMs may be to high for your finishing polish/compound. Ive got this typ of spot shining / dulling when buffing cars with a polish not made for high speed buffing.It dryes while working with it due to the heat build up from buffing.
Old 10-14-04, 08:54 PM
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The best polish I've found for a bright finish is called Semi-Chrome. It's made in Germany and can be purchased at auto supply or truck stops. A little dab on a cloth and a lot of elbow grease bring chrome and stainless to a mirror finish. Next you'll need a coating to keep it that way. I'm still looking for one that bugs won't stick to.
Old 10-23-04, 11:16 PM
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I'd suggest a few of the following options. If the piece is magnetic/steel you might want to get the piece powder coated. You'll need to remove the piece so they can back it at 300 deg. They make a color that is a bright luster type chrome look. Should give you the look you want and is very durable. If the piece is non magnetic/aluminum I'd suggest using a product called Wenol. Stuff works wonders on every kind of metal and sells for about $8 a tube.

Good luck,

Old 10-24-04, 05:08 AM
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voigtsound: if you want a mirror finish on metal that is already pretty smooth to begin with (ie - a turntable plinth) then get the item electroplated. Chrome is the obvious choice, but nickel and aluminum plating can also produce exceptional finishes. An alternative (or additional) process would be to have the plinth "lapped". Lapping is done by putting the item in between counter-rotating wheels with rouge as the grinding medium. As you might imagine, this produces an extremely flat surface and having a very flat surface is the key to making a mirror. If the plinth material is cast and/or a metal not particularly lustrous on its own (steel) then you can follow the lapping with electroplating. At any rate, there's no way I'd try to polish so large an area as plinth by hand to a mirror finish - not for a $100, anyway!

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