My first attempt at polishing a motor was a Mk-25 project that I called "Project Quicksilver" or "Johnny Cash". as in one piece at a time…. This was built from parts that came from scrap piles. I had recently started to weld aluminum and I wanted to see if my welds were good enough to polish them out. That lead to the entire motor being polished. These parts were all in really bad shape. I had to weld the cowls, drive shaft housing, swivel bracket, recoil housing, and the lower unit not only didn’t have a skeg, it had been assembled with the wrong bearing and a gear went through the side of the case. The previous owner then covered the hole with a huge gob of JB-Weld. I figured I couldn’t hurt anything! 😆 I hit my welds with a disc grinder and then went from there to a sanding block with 180-220-320-400-800-800-1200 and them used a wool pad. The next project was a KH-7 that I started with left over parts from this project. As it was left over from "Cash", I called it "The change"… 🙄
The biggest thing I learned is that you can’t go with too fine of paper too soon. However, don’t use 80 grit or you will work your tail off trying to get rid of the sand scratches. With each different grit, I would sand in a different direction so I could tell if I left any sand scratches from the previous grit. This worked quite well.
Steve
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