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Polishing Flat Aluminum Surfaces
wrote:
Hi guys;
I'm looking for some ideas from any of you with experience in metal
polishing. I often make up aluminum parts which need to buffed out to a
level of perfection that will look good under show chrome plating. A
typical part, like a couple I made up this afternoon, is made from
0.090 6061 plate, about 3" x 4" with a milled opening and a dozen
various sized holes.
The problem is, what's an efficient way to get the scratches out of the
flat surface and bring it up to a mirror shine? The last part is easy.
Once the surface is up to about 1500 grit level, it's no problem to
buff it out with a sewn cotton wheel and tripoli compound. How do you
get from scratches to 1500 grit while keeping the surface flat and
even, without excessively distorting the holes and openings?
Right now, I'm hand rubbing the surface with a hard rubber block and
various grits of emory paper. I start with 320 and go through 500, 800,
and 1500, using drops of WD-40 as a lubricant. This works pretty well,
but it's very tiring and takes way too much time. I need a power method
of doing this.
I don't do this regularly, but it does come up on occasion. I use wet
or dry
sandpaper on a hard surface, like a surface plate. If you wet the back
of the
paper, it may stick all by itself, without gluing it. (But maybe that's the
purpose of the hard rubber block.) I use water as the fluid, and lots
of it,
and wash the sandpaper frequently under the faucet to remove aluminum
buildup. I could probably rub the part for only a couple of minutes per
grade of paper.
I suppose a belt sander could be used with the appropriate abrasive. Don't
look in the local hardware store, look at Norton or other commercial
abrasive makers.
Jon
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