Suggestions on polishing metal

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Daniel

Daniel

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Jan 1, 2004
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Reno, NV, USA.
Recently I have been trying to polish the brass for the 50 cal BMG kits. so far I am not all that happy with the results.
The MM does not seem to get the job done nearly as well as it does on wood or plastic. Reading the info on MM I also realize that they sell an alternative style for metal polishing.

as for what I am doing now I start with 400 grit because there is a lot of dirt and rough spots to try and remove. at the very best these are not going to all get removed as this is pretty abused brass when I get it.
I then work my through grits up to 1200 (the black stuff)
I have been trying to finish up with the finer grits of MM but no matter what I do I end up with very small scratches. polishing with MM only highlights these not removes them. I then finish up with brasso. I am looking for a chrome shine polish if I can get it so anyone with metal polishing info please pass it on.
Thanks
 
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I have no real experience except with some varieties of jeweler's rouge. Is there an art supply store near you that caters to metalsmiths (ring makers, etc.)? Also check out Rio Grande Supply (www.riogrande.com) - they sell everything.

Marc
 
Scotchbrite pads, the red ones. McMaster-Carr item # 46365A73 They also have more aggressive pads, but these will put a shine on and clean up and remove a lot of crud. I have polished a lot of metal with these.
 
I agree, one of the coarser varieties of scotch brite to prep the metal for polishing is probably a good idea. I tend to doubt that the scratches you are seeing are being added by you in the polishing process, they probably exist in the raw brass before you start and you are just uncovering them. Remember, to achieve a truly scratch free finish, you must remove material over the ENTIRE piece to the depth of the deepest scratch that exists when you start. Then polish without adding any new ones. I would suspect that a large portion of casings start out with flaws that make this level of finish very difficult to achieve.
 
After MM, I use cotton cloth and metal polish (liquid form) on my knives (then oil).

If you coat the brass after, make sure you clean it well with rug and alcohol well. Some of these polish have corrosive additives to help "cut" faster.
 
I sand with fine sanding disks then go straight to polish with a large cotton wheel and the white compound made for stainless steel. It works well for just about any metal. Places like Enco and MSC sell the compound.
 
Daniel

When I was doing my cartridge pens preping for powdercoating, I noticed the swirl marks too and do not think this is something that can be totally gotten out. Maybe if you did an acid wash or something of that nature. But what I did is used those nonwoven pads I use for smoothing wood finishes. I was able to use the grey which is the finest. You might have to use the maroon or even the white . Really brings it to a nice shine. Then hit it with some brasso. After that to put a mirror finish on it I hit the polishing wheel and use the green stick which is made for brass. To me it does as good as of a job as I can get without too much work. I think any time you are using an abrasive and sanding with a turning machine you will have scratches. Now to get a finish like the puzzle pen that was just shown has to take on a different technique and maybe he will share it with us.

I will be going through the same thing when I prep your 50 cal pen kits for powdercoating. That does not look like any time soon because it is so darn cold here and I need to do this in the garage because of the fumes from the powdercoating. I do make sure I wipe the cartridge down with acetone before applying to get all fingerprints off. Has worked quite well so far. Good luck.
 
For brass, I sand with Abralon at 180, 360, 500, and 1000. Then I move to a buffing wheel with brown tripoli polish, and then one with white diamond. This tends to work well for me when I do knife bolsters and such. You may find you want to go one more step with green compound, but I find it unnecessary.
 
Thanks folks. It looks pretty much across the board I need another type of polishing method than sandpaper. This helps me limit the list of what to try. I guess it might be time to take another look at the Beall buffing system eh?
I also suspect that some of the problem is in the brass itself as is mentioned above.
Thanks again to all the folks that always seem to have an answer.
 
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