Polishing, sandblasting, and washing parts
As parts came off the GT250, I quickly realized I’d need to learn how to polish all the various bits of aluminum (40 years of corrosion); something I’ve never done before.
I checked out a number of how-to guides on-line. Some folks were doing it by hand, using all sorts of household chemicals, etc. That just wasn’t going to cut it for me (as my Dad says, “work smarter, not harder”).
Ends up it’s very simple to polish aluminum – here’s a nice video of the technique (he’s using a big electric polisher, but the idea’s the same).
I ran over to Northern Tool and grabbed a cheap 1/4″ die grinder and some buffing wheels and polishing compounds (the compounds will indicate what metals they can be used with). The link for the buffing wheels/compounds isn’t exactly the ones I got though. They also sell a package with two 3″ wheels and compound for like $4-$5 dollars (their site doesn’t have it listed). Wheels bigger than 3″ really slows down the air polisher as well (probably want to avoid them). Be sure to squirt some WD-40 or similar into the air inlet of the grinder/polisher every day you use it – else the tool really slows down.
Some of the aluminum parts on the bike have a clear-coat finish on it (usually yellowed at this age). The polisher will remove that as well (which is fine and necessary). They did this to prevent corrosion from forming. You can leave the aluminum naked (but you’ll find it picks up fingerprints very easily). Others have reapplied clear-coat to the polished aluminum. I decided to try ShineSeal – it supposedly gives you the best of both worlds (a nice polished look and prevents corrosion)…we’ll see how it works.
I also used a sandblaster cabinet with glass beads (don’t get media that’s more abrasive or you’ll pit the aluminum). A sandblaster cabinet can be had for ~$100 new, and a better one if you get it used. This was used when the aluminum was really in bad shape. You could eventually polish through it, but the glass beads made quicker work of it – after blasting it you can polish it easier.
Finally, as you polish you’ll want a rag of some sort to clean off the buffing wheel (you can see the guy in the video above doing that from time to time). It helps from transferring the stuff you polished off to the new areas you’re working on. One last tip, the spent polish will get into crevices and smaller details on the aluminum (like lettering). I found it wasn’t easy to clean off until I squirted some brake cleaner on it…then it melted right off.
Here’s a before/after look at the aluminum (they are different parts, but both looked the same when I started), click on the photos to zoom in: