Refinishing Solid Brass Parts

One of the nice things about restoring old television sets is that the manufacturers were still using quality materials.  They didn’t use plated steel or plastic parts for decorative purposes.  They were still using a lot of SOLID brass.  Brass is made mostly of copper with a small percentage of zinc.  When the zinc is added to the copper it causes the copper to turn from the reddish color of a penny to the yellow gold color we are familiar with.  Depending on how much zinc is added to the copper at the foundry, you will get various shades of yellow.  The great part about solid brass is that it can be easily refinished. The following is a short tutorial on how I refinish solid brass parts. 

There are various methods of refinishing solid brass such as using Brasso brass polish, like we used to do in the military, but that’s a lot of work because you must first remove all the lacquer coating from the brass before the Brasso will be able to remove the tarnish.  And removing old lacquer from brass parts is very labor intensive when you do it by hand.

I use power polishing machinery to do my brass refinishing.  I have access to the polishing department at my brother’s factory where we have 16 polishing stations with central dust collecting.  You can do the same thing at home if you have a large electric bench grinder that can be adapted to use the polishing media that I show in this tutorial.

This photo shows the brass trim pieces that go around the safety glass on an RCA CTC4 cabinet.  You can see how very dark color the tarnish is on these brass pieces. 

The media I use comes from 3M.  The Scotch Bright Discs contain a very fine grade of aluminum oxide abrasive.  These discs can be obtained from most 3M industrial abrasive suppliers. Here is a link to the 3M catalog which tells about the discs I use. 

The maroon discs you see in this next photo are 3M Scotch Bright discs.  They are mounted on a polishing arbor that spins at roughly 3000 RPM.  This photo shows a brass trim piece being introduced into the Scotch Bright disc to remove the heavy layer of brass tarnish and the old layer of lacquer covering the tarnish.  There is a correct way and an incorrect way to use a spinning Scotch Bright disc.  You must always be sure that the disc is dragging the part you are polishing, and NOT PUSHING the part toward you.  In this photo you can see that I am placing the brass part underneath the disc.  The polishing disc is rotating just like a wheel on a grinder, where the top edge of the disc is rotating toward me and the bottom edge of the disc is rotating away from me.  You may ask why this is so important. Here’s the deal, if you try to polish with the wheel pushing the part toward you, there is a very real possibility that the wheel could catch the end of the part you are polishing and violently throw the part out of your hand, and in the process cause severe damage to either the part or yourself.  There is a skill to machine polishing and this is one of the rules that you must never deviate from, or you risk injury to yourself.

After all the tarnish and old lacquer have been removed using the Scotch Bright discs, I use 0000 steel wool to “burnish” the part.  The Scotch Bright leaves a nice brushed satin finish, and if you want a brushed satin finish, you can skip the steel wool burnishing.  In this case I wanted to have a smooth polished brass finish so I used the steel wool to burnish the brass to a higher luster.  This photo shows the steel wooling process.  In our polishing department we have polishing arbors operating at a low 400 RPM over which we wrap 0000 steel wool.  The steel wool will take the satin finish created by the Scotch Bright discs, and it will burnish the brass to a higher luster, or polish.

The final step in either case, is to spray two coats of clear lacquer over the newly polished brass parts.  I use a common commercial grade of nitrocellulose lacquer thinned with 2 parts lacquer thinner to 1 part lacquer.  You could use clear lacquer in a spray can but not all lacquers in spray cans will look good.  You will need to test your lacquer on a sample to be sure you are happy with the results before you use it on your polished brass parts.  Prior to spraying, wipe any finger prints off the newly polished parts.  Finger prints left on the brass will cause the brass to tarnish underneath the newly applied clear lacquer.  Prior to spraying the clear lacquer, I always wipe all my polished parts with a paper towel moistened with lacquer thinner in order to remove all traces of finger prints and dirt.
This photo shows the brass parts on a plastic grid which I use for supporting the parts while being sprayed with lacquer.

Here is a photo of the refinished brass parts and a comparison photo showing he before and after.

Good luck on your project.