Author Topic: I want to know the plating of cylinder of Douglas s6 / C31 / D31  (Read 322 times)

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Offline yoshimasa negishi

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Hello
I am riding on Douglas in Japan.
I got a new 1931 model D31 600cc
I want to start restoring in summer

I have a question.

Is the cylinder nickel plated, not black painted?
Which type of nickel plating is preferred, electrical or electroless?

Offline Doug

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The cylinders were originally nickel plated.

Electroplating is considered to have the better bonding and is how the cylinders would have been originally done. But my understanding is that it is difficult to get a uniform coverage at the root of the fins so many restorations have been using electroless. I do not know how well the electroless holds up to the heat, as many of the bikes that I have seen restored with re-plated cylinders (example: early Indians) are not used but just diplayed in collections and museums.

-Doug

Offline yoshimasa negishi

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Hello Doug
Thanks for any useful information
I ask the plating company about the heat resistance of electroless nickel plating

Offline Doug

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I ran into a similar problem with copper plating which is used as a heat treatment carburizing mask. Nowadays they use paint-on compounds to prevent absorption of carbon during carburizing; but copper plating is the traditional method and more certain. You do not rely on a employee carelessly painting areas too thin, or getting splatter on areas that should not have compound. You plate the entire part and machine away the areas that you want to absorb carbon.

The electroplater used an alkali process, apparently more environmentally friendly than the traditional acid copper plating. However the copper plating blistered, even at the relatively low temperature of 135C post-plating bake to drive off any absorbed hydrogen during plating. It would not have survived the heat treatment temperature. The parts were re-done with the acid copper plating and it baked and heat treated perfectly.

-Doug

Offline Dewey

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Like most things/processes, there's a reason the traditional means were used - they worked! There's no question that there are more cost effective or environmetally friendly approaches to be had but certainly lose durability. A good pressure washer will blow off latex paint but struggles with oil base. Plexiglass will never substitute real glass. Decaf vs real coffee. The list goes on -.

I had the Fultons Mastif cylinders nickel plated after copper using traditional means and it came out beautifully. The hard part was finding an establishment that would do it.

Dewey