Polishing aluminum?

[shoestringmariner]

For those with the highly polished aluminum motors, what do you use?

That Zephyr in a recent thread looks drool worthy. I have a little 2hp that I will never restore, but I’d like to make a pretty wall display out of it

[20mercman]

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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[Alan Pelot]

Steve,

Do you use regular sandpaper/emery cloth?

It is all by hand, except for the welds?

Also. Do you use any type of polishing compound?

Very interesting. I have tried to get this look. I have tried a wire wheel on my bench grinder, a polishing pad on my bench grinder but it is hard to get in the cast areas. I have tried rubbing compound with 3m pads. That worked well but I couldn’t get the real mirror shine.

I never thought of sandpaper.

Thanks. Alan.

[20mercman]

Yes, I use sand paper. Wet sanding starting with Windex on the 220 grit and finer. All by hand on these two projects here. I did use a DA on my latest KG-7 tank ring that was awful. The corrosion is like a cancer that goes deep sometimes. In this case, I used 180 grit on the DA until I was able to get to clear metal. You also have to be careful not to sand out details or casting trademarks etc. if you want to keep them. As for polishing compound, I have used Mothers, and just about anything that you can put on a wool pad. I mounted the wool pads on my drill press, and worked it that way. You have to also be very careful to not let the chuck contact your work, or you have to sand out the flaw all over again. I had pads for Dremel tools for the nooks and tight spots.

Steve

[Alan Pelot]

Thanks so much. Can’t wait to get home from work and try it.

If I would do the wool pad by hand I am assuming I wouldn’t get the mirror finish?

Alan

[2fast4me]

I will cut strips of wet-dry sand paper and place packaging tape on the back which will reinforce the paper and provide a handle for my "tool" (I’m to cheap to go buy the stuff on a roll), then a shoe shine motion across the part to get it leveled, then change directions with a finer grit and repeat till I get the Finish that I want.
Jim

2Fast4Me

[Mumbles]

Using progressively finer grits of wet and dry is the key. Allow yourself lots of time and have a big tub of elbow grease on hand. To get a mirror finish, the parts have to be buffed after to remove any fine scratches. One word of caution, DON’T use Twinkle or other coarse polishes on any finely polished parts. They will clean a tarnished part but will dullen a mirror polished one. Then it will be back to the buffing wheel. 🙁

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[Tubs]

quote alanp:

Thanks so much. Can’t wait to get home from work and try it.

If I would do the wool pad by hand I am assuming I wouldn’t get the mirror finish?

Alan

A "Boat House Repair" is one that done without having tools or the skills to do it properly.

[nali]

3M 2" pads can be also useful sometimes.
Not those like sand paper, but the ones like Scotch Brite.

In fact polishing is easy, it just care times 🙂
For sure, a few tricks and tools help, but there’s nothing magical.
Sand, sand, and sand again.

[shoestringmariner]

incredible looking work…maybe a bit more work than I am into at the moment. Maybe after I retire lol

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