I restore antique espresso coffee machines ('40s - 60's) for a hobby.
When it comes to metal finishes, I am a rank amateur.
I have would like to improve the quality of my restorations by learning
how to do a neat job of refinishing brushed panels. I guess that this
entails using various grades of wet and dry sandpaper, or perhaps
scotchbrite pads. My question is, how do I achieve an even finish?
I would be most appreciative for any pointers or links to helpful
Trying to get a consistent grain pattern is a RPITA. If you are trying
to touch up a small spot, it always wants to show. The original finish
was put in using an abrasive wheel with a certain size abrasive grain
and a specific pressure. This gives a depth of cut and distance between
cuts that you are trying to match. Good luck. You can try various grades
of sandpaper but ..............
Best approach is to completely redo the whole surface using a flap wheel
on a bench grinder or better yet, a flap wheel on a hand held angle
grinder. A light touch, long strokes, works fine.
www.mcmaster.com search on 'flap wheel' they come in sandpaper style,
non woven, the 3M Scothcbright ones, etc.
Keep in mind that the aluminum pannels are quite soft, stainless steel
is much harder, and a lot of the pannels are brushed steel with chrome
plating. Be sure you know which one you are working with before starting
in. The chrome plated ones really need to be stripped, rebrushed, then
I believe the process is correctly referred to as graining. I did quite
a bit of it when I worked in a finishing department in a machine
Most of the prts that I grained were thick welded stainless parts (not
sheetmetal), on a graining table (machine) that was used to remove the
mill finish and make welds disappear.
The machine was like a huge belt sander (about a 6" wide belt), but the
belt area between the hubs was open, and traveling over a gliding
table. A padded block was used on the back side of the belt, to press
the belt down to the workpiece. The table would be manually moved
in/out perpendicular to the belt direction, to get full coverage of the
The finished workpieces looked completely uniform in appearance. The
abrasive was traveling in a straight line, and in only one direction.
The critical part was to not round over the edges, by by keeping the
hand block from travelling over them.
Appliance parts can be many different types of metal, as RoyJ
suggested. If you completely disassemble the machines, refinishing the
entire (flat?) panels would be easier to get a uniform finish, than
trying to touch up areas while the machines are assembled.
Seeing the back sides of the parts would help you determine if the
parts are stainless, anodized aluminum, or plated steel. The stainless
parts wouldn't require any other processes other than graining.
The other parts will require additional processes (chemical and
electrical) to retain the bright appearance.
When working with abrasives, using different carriers will affect the
appearance of the finished part. Using a wood block, a steel block, or
a plastic/rubber block will give different finishes on the same metal,
using the same abrasive.
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