Tips for Successful Metal Polishing


Tags: how to, bikemaster,

1983 Laverda RGS clutch cover

I've never been a particularly patient person, but I'm learning. And nothing helps teach patience like a project that demands patience. Take metal polishing. On the surface (pun intended) it seems like a simple proposition; clean the surface first, slap on some polish, work it in with a clean cloth and voilà, a perfectly polished and gleaming surface results. Unfortunately, when you're working on old iron, it's not always quite so simple.

On the bikes we regularly work on around here — mostly an odd assortment of 1970s to early 1980s Japanese and European road bikes — the major issues we see with metal surfaces are pitting and surface degradation from constant exposure to the elements, and — especially on mid-1970s Japanese bikes — hazing of polished engine cases with clear-coat finishes.

Surface degradation from exposure is a problem experienced by all bikes that see regular use. It can easily be kept at bay by simply cleaning your bike after every ride, or at least every other ride. A quick wipe-down of polished surfaces, followed by waxing, will add years to metal and painted surfaces, protecting them and staving off mild oxidation. It’s a best practice we know we'd do well to follow, but often don't.


While getting a good sheen on our clear-coated engine cover — the subject of this issue's How-To — we learned one very important lesson: Successful polishing takes lots and lots of elbow grease.

There are, unfortunately, no magic fixes. There is no one product that miraculously cleans and restores neglected surfaces, returning them to a brilliant luster with little more than a light rubbing. The hard truth is, once a surface has diminished significantly it takes work, and a fair amount of it, to restore that surface back to its original sheen.

11/13/2013 5:28:49 PM

I find it helpfull to use the wheel with smooth light pressure strokes one "line" across the piece overlapping the previous pass. A 3500 RPM table-mounted grinding wheel (fitted with a Sisal type polishing wheel, one for each grade of compound) is a sound investment and will save hours of time and elbow-lube. The next series of passes is applied at 90 degrees to the previous. Use light pressure letting the wheel and compound do the work and avoiding excessive heat buildup that can warp the piece. A wet terry cloth towel and/or a bucket of water for quick cooling dips is handy. Patience is key. It will take four times longer than you initially expect! Also, this is the time to true and flatten joints on covers by sanding in figure "8" motions on a glass plate ore machinist's table. I trued my valve cover joints by sticking 400grit wet/dry paper on the angle-table of my drill press as it's nice and flat. My Brit is oil-tight... ish. It's easy to clean a polished surface later with a simple hand buff-up with "Mother's", so I don't use a sealent or clear-coat.

4/6/2013 3:37:25 AM

Iv done a lot of buffing out parts on badly scratched cases i start with 220 grit 320 400 600 800 1000 then i go to the buffing wheels i start with the grey compound on a sewn cotton wheel then i go to the white compound on a loose cotton wheel its a lot of work but it pays off in the long run with a mirror like finish

gerald estes III
4/4/2013 1:14:56 PM

ride 'em dont hide 'em....never, i repeat never submerse a carbureator into a cleaning solution. i helped out at a dealership one spring...they offered indoor winter storagfe to many of their customers who purchased "vacation home scooters'...the staff mechanic's/service managers procedure was to dip the carbs...i got there a couple seasons later and found the zinc castings resembled concrete cinder blocks covered with lichens - go figure.

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