VJMC Tech Tip
Bringing Back the Shine
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By Andre Okazaki
I've been polishing my own aluminum parts for years and have had success with all but the most damaged parts with deep gouges or road abrasions. The whole process takes some time and patience but can save you a lot of money that you could put into another part of your restoration project.
If the part in question has a clear coat of some sort, the first step is to remove it. What I have used in the past is paint stripper available at your local hardware store. Before applying paint remover make sure you have removed anything attached to the part you are stripping of the clear finish. Plastic or rubber parts will likely be damaged if not removed. Follow the manufacturers directions but use a plastic scouring pad instead of any abrasive material which could scratch and damage the finish. If the clear coat is intact but dull, cracking or yellowing you may be able to just use polish once it's been stripped.
Once clean you need to take a close look for deep scratches, nicks or any marks which will need to be smoothed out before polishing. Small marks can be removed by using 400 grit wet/dry sandpaper, keeping the paper and piece wet at all times. If there are any marks that look too deep, you may need to have that area welded to fill the impression. When removing marks Make sure not to sand in one small spot. The object is to remove a small amount of material from the surrounding area so you are not left with a low spot which will show when you're finished. Do not sand areas where a gasket or seal is to be fitted.
After all marks are removed, use 600 grit sandpaper and wet sand the entire part, paying special attention to the areas where you used 400 grit. Using 800 grit then 1000 and finally 1500 wet sand entire part until finish looks smooth and even with no marks.
When satisfied with your sanding, you are now ready to polish your part to a mirror finish. I have tried a couple of different ways, all of which work well. The part can go to a shop to have the final polish done by a pro which because of your hard work will literally take a couple of minutes and cost very little. I use an automotive electric buffer as used to polish your car after waxing. For this purpose my favorite product is called Autosol but any good quality metal polish should work well too. This is not as good as a high speed polishing wheel like the pros use but if you are restoring on a budget you'll find the results comparable. Any areas where the buffing wheel cannot reach must be polished by hand or you can use a special polishing tip for your drill or dremel type tool. The quality of the finish depends on the wet sanding. The more care and time spent the better the end result will be.