Demountable rim plating

[Humblej]

Went to the Benson Ford Research Center today to see demountable rim drawings. Saw drawings for 30 x 3.5, TT, and balloon. Manufactures included Ford, Firestone, Kelsey, and Hayes. There must have been 30 or more drawings so for time constraints, I just looked at the most recent drawings for the different part numbers. Of the clincher rims, some were galvanized, some were zinc. As to the balloon split rims, only saw Ford drawings, or I assume as no manufacturers name was identified, all were zinc. TT solid tire rims were zinc. This contradicts the Les Henry book Model T Restoration Hand Book (that was all we had back in the early 1970's) and which I quoted a few weeks ago in response to a question someone posted regarding the correct color to paint his rims. Well with the conflicting responses he received it got me thinking and gave me a reason to visit the center again.

[George Andreasen]

I thought zinc plating WAS galvanizing................

[George N Lake Ozark]

Thanks for that info Jeff. Always wondered about the Les book and remember the Cad. reference.
I have wires on my car but wonder what the correct paint color that everybody could agree to.
A number of states have been banning certain plating processes. My former state of Kali comes to mind.

George n Lake Ozark

[Steve Jelf]

Of the clincher rims, some were galvanized, some were zinc.

George is correct. Galvanizing IS zinc plating.

See my last post explaining the subject in more detail here: viewtopic.php?f=2&t=1880

[Mark Nunn]

I thought zinc plating WAS galvanizing................

You are correct but there are variations. Hot dipping is galvanizing and typically leaves a heavy coating. There is also "barrel plating" where zinc is electroplated with a much thinner coat thickness. That is what you commonly see in modern hardware.

[SurveyKing]

Not sure about zinc plating, but I have had two sets of rims Cadmium plated as I was told that is the closest thing to the zinc plating that was originally done on the demountable rims. Be interesting to see what others think, I know a lot of folks just paint them silver, but I have always preferred the cadmium plate myself.

[Steve Jelf]

The different types of galvanizing, and the fact that cadmium plating came into industrial use after the Model T was out of production, are explained in my link above. The closest thing to zinc plating is zinc plating (galvanizing).

[Allan]

Zinc plating is an electroplating process, just like Chrome and nickel and copper plating. Items to be plated are wired together and current passed through them which activates the chemical bath in which they are immersed. Barrel plating works the same way, except the barrel is wired for current and the components revolving within the barrel make intermittent contact to make the plating process work. These processes result in a smooth, evenly applied coating.

Galvanising is a form of zinc plating whereby the parts to be plated are immersed in a vat of molten zinc. This results in a thicker, more durable coating, which can be quite textured and can also leave dimples/pimples of zinc requiring some detailing if they are in critical areas.

On our Canadian sourced cars,I have seen a few galvanised clincher rims, but the vast majority were electro plated zinc, most of which has long since departed.

Allan from down under.

[Steve Jelf]

Most dictionaries will tell you that the term galvanize, when applied to metals, means to coat with zinc. Hot dip and electroplate are two methods of galvanizing. The term originally referred to action produced by electric current (refer to Galvani's experiments), but came to be used for both methods. Because of the differences Allan described, hot dip galvanizing is preferable to electroplate galvanizing for rims.

[Humblej]

Interesting comments. Still wounder why the different finish note specifying either galvanize for some and zinc plate for others. One of the reasons I like reading old engineering drawings, like some people study classical art.

[Steve Jelf]

You say potato, I say potahto... Maybe different people preparing the drawings preferred different terms which mean the same thing. Is that thing under the hood an engine or a motor? Ford used both terms in different places.

[TFan]

There used to be a product in a spray can called "Cold Galvanizing" how would this work for our rims. Jim

[Allan]

My dictionaries agree with Steve. However, in practice, the difference needs to be recognised. Hot dip galvanising is much more durable as a rust preventative coating, because it is considerably thicker. In hardware terms, a zinc plated bolt is usually drum plated using electro plating to deposit a thin coating. This is the coating many of us spend time removing when using such hardware in our restorations.

Galvanised bolts using hot dipping need to be machined undersized to allow clearance on the threads. They are different creatures. These bolts will stand up to exposure far better than zinc plated bolts. They are a must when used with CCA treated timbers. Hence the need to specify galvanised bolts rather than zinc finish bolts.

Allan from down under.

[Steve Jelf]

I buy cans of old galvanized nails at auctions because they're hot dipped. New ones from the hardware store are thinly electroplated and turn to rust spots in a few years.