Aluminum Reversible Pilot Seat Z-legs on c.1972 COHASSET II

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Imfishy1
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Aluminum Reversible Pilot Seat Z-legs on c.1972 COHASSET II

Postby Imfishy1 » Fri Jul 15, 2022 9:35 am

I think the Z-legs on the Reversible Pilot Seat are made from aluminum [on my c.1972 COHASSET II boat].

Q1: what is a good method to restore shine to aluminum?

jimh
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Re: Aluminum Reversible Pilot Seat Z-legs on c.1972 COHASSET II

Postby jimh » Fri Jul 15, 2022 9:42 am

I can't speak authoritatively about your particular boat, but generally the Z-legs on a Boston Whaler Reversible Pilot Seat were not made from aluminum. Typically some sort of molded plastic material was used, and here I don't me some plastic as used in a child's toy but some sort of combination of resins and fillers that could be used with a mold as in fiberglass-reinforced-plastic (FRP) constuction.

Considering that the production epoch was c.1972, I can only speculate that perhaps the first production Z-legs were made from aluminum, although it would seem to me that choice of material would be unusual. I would expect that the legs would have to be fabricated from a casting of aluminum. Usually Boston Whaler would have been more crafty than that with regard to cost and difficulty of making a part like a Z-leg.

One good test for identification of aluminum is electrical conductivity. A molded fiberglass part certainly won't exhibit any electrical conductivity.

jimh
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Re: Aluminum Reversible Pilot Seat Z-legs on c.1972 COHASSET II

Postby jimh » Fri Jul 15, 2022 9:51 am

Imfishy1 wrote:Q1: what is a good method to restore shine to aluminum?
Aluminum encompasses many alloys, and some will have a naturally bright lustre finish. Others will not have much luster. I would expect that any cast aluminum component would naturally have a dull finish.

Aluminum exposed to weather usually develops aluminum oxide as a surface. I don't know of a particularly specialized cleaning agent for aluminum oxide. I'd try wet sanding with relatively fine grit emery cloth and using WD40 as a wetting agent. Test on a small area before embarking on the whole part. I have used that method on large radio antennas made from aluminum tubing in order to restore the electrical conductivity of telescoping tubing joints.

jimh
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Re: Aluminum Reversible Pilot Seat Z-legs on c.1972 COHASSET II

Postby jimh » Sat Jul 16, 2022 1:16 pm

A bashful reader sent me some correspondence that attests the original Reversible Pilot Seat Z-legs were designed by Bob Dougherty and were made with cast aluminum. The aluminum legs had a tendency to break, and they were replaced by the type I mentioned, a cast fiber-reinforced plastic Z-leg.

My correspondent also recommends wet sanding with lots of water as a means to restore the finish on an aluminum Z-leg. That is probably much less expensive for an aluminum part with a lot of surface area than the WD-40 I mentioned, which for my use was also particularly good with regard to its electrical restorative properties; and the areas I wanted to clean up were much smaller.

superdave_gv
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Re: Aluminum Reversible Pilot Seat Z-legs on c.1972 COHASSET II

Postby superdave_gv » Sat Jul 16, 2022 1:33 pm

Thank you Jim and your bashful reader. This solves a curiosity about the aluminum z legs on my former Cohasett II.