How to refinish cases for an OEM finish?

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susej1981
Posts: 5
Joined: Tue May 04, 2021 11:15 pm

How to refinish cases for an OEM finish?

Post by susej1981 »

Hi!

In the process of doing little restoration projects and wanted to refinish the side engine covers. I see originally it used to be a clearcoated brushed finish. How can a finish like this be best achieved?

Would polishing using a 3M rouge scotchbrite pad followed by some aluminum polish yield same results? Possibly wet sanding up to 400 grit and then using aluminum polish maybe?

I've seen the sides be mirror polished but not sure if this is how they came from the factory.

Appreciate the help!

Kettle rider from Chicago, IL!
teazer
Posts: 957
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: How to refinish cases for an OEM finish?

Post by teazer »

Looking at a bunch of period magazine articles and adverts, the cases appear to be polished but to a much less fine or mirror finish than we obsess over today.

The castings were probably machine polished with two grades of polishing compound stopping with whatever the equivalent was of red rouge. Production costs would not have allowed for the extra time required to get close to a mirror finish.

You could try a harbor freight buffing machine with say a 10 inch yellow wheel and use red rouge from harbor freight or Eastwood. Get a sewn cotton polishing wheel. the yellow ones on ebay allow for faster material removal. When you use a buff, wear goggle and gloves and allow the parts to get hot from the friction and the wheel will turn black as it removes aluminum and oxide.

You could try 400 grit (wet) plus say Mothers but it's hard to get all the swirl marks and scratches out. What you are trying to get is a finish that is even and smooth and with a moderate polish. I used to use progressively finer grades of wet and dry down to 2000 grit - always with lots of water and polish by hand but a cheap buff saves days and also saves you from absorbing all that toxic aluminum through the skin on your fingers.

BTW, Which side of ChiTown are you on? We are up near the WI border if you want to drop in and compare notes.
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