How best to achieve an unpolished look?

[Georg]

Ok, so I don't like shiny things, and in particular not shining metal on a steel guitar. Problem is; it is difficult to get, or even make/mill, parts that don't have a somewhat polished look, and it seems to be preferred by most.

With reference to this thread: viewtopic.php?f=19&t=108, is it possible to "un-polish" aluminum parts so they get a permanent look more like the non-polished part presented there?

In addition to looks I have other reasons for trying to achieve a perfectly uniform, non-polished, somewhat "bubbly" surface on most metal-parts in a PSG. The right "sharkskin" like surfaces on parts that rub against each other, like some parts in a changer, actually reduce friction compared to perfectly smooth-polished parts, reducing the need for lubrication to prevent the parts from sticking together. The "sharkskin" surface does of course have to be very hard to make its non-stick properties last.

Maybe a form of Teflon-treatment can be used?
I know next to nothing about surface-treatment of aluminum, steel, etc., so any and all ideas and info are welcome.

[Scott Howard]

Glass beading and anodized are what comes to my mind. Powdercoat is another option. Not sure if it is what you are talking about. Possibly Glass bead and follow with a clear powdercoat .

[Bent]

Georg, I don't know if you'd like this, but I seemed to get a smooth but matte look on some parts(for example end plates) by using a 400 grit sanding disc in my random orbital sander as the last step.

[Allan]

I am so with you on this Georg. Anyone who doubts what you say regarding the non-smooth surface and lubrication only needs to try out a six string guitar with the newer style satin surface neck then one of the older style shiny ones. It is so much easier to play on the less glossy neck. The more complete the contact is, the more likely there is to be a sticking effect.

Besides, I like the look of a nice even matt effect too. It is very hard to achieve by hand though. I like the idea of glass beading or anodizing. As a bonus, anodized aluminum takes subsequent coatings in a way that polished aluminum will not.

I am wondering if acid etching is another option. Anyone know about that?


Regards, Allan.....

[bobby burns]

I like a matt finish on parts sometimes too. The best matt finish is achieved by buffing to a shine and then dulling the finish, but if skipping the buffing is part of your goal, (it often is mine), then bead blasting is a good idea. I have cut a scotchbrite pad into a circle and and mounted it in a grinder to achieve a matt finish, but I only use this on larger parts that I can hold without the pad grabbing it. If your not careful, it will take it from you without warning! I have also used a rock tumbler with fairly coarse media. Often my goal is to remove/blend-in tool marks and just get a more uniform surface, not a shine. I often just hit the roughest spots with some sandpaper, and put them in the tumbler. If you have a rock tumbler, after blasting or sanding, or scotchbrite, or whatever, the tumbler finishes the job very nicely, and it does the work while you do something else. Of course, the tumbler only works if you parts fit inside the tumbler.

[Georg]

Thanks guys, I now have some methods to look into and later discuss with people in workshops in my area.

[bobby burns]

Georg, I was polishing some parts today, and thought about your question. When I polish large cast parts, I start with various sanding machines. After getting a part sanded flat on the belt sander, I go through progressively finer grits on a random orbit sander. after I got to about 220 grit, I think I had a look you would have liked for your application. The sander leaves very fine random swirls that are fairly attractive.
This forum is eventually going to push me over the edge to get a digital camera.

[Georg]

Thank you, Bobby.
I may try "random swirls" for visual appearance. For surfaces on mechanics I plan on testing out careful sandblasting when I get around to it, and see how that works out.

[Bill Ford]

Georg,
When you get your part(s) cleaned and ready to do the finish, with the sander (random orbital)running, touch down with a medium firmness and lift quickly, move about 3/4 over from there and repeat until you cover the part. That's the way I've seen it done...matches the Emmons style finish. It will take some practice to get it right. Beadblast parts look good on the underside.

Bill

[Georg]

Bill,
Some testing show that it is impossible to get a good result with a sander on anything but relative flat surfaces, so I think careful blasting all over will work best for me.