Rechroming early door handles made from Zamac (zamak)

[Semjon]

Hi everyone, while in the process of building up my car we ran into the door handles which are really pitted.

My idea was to rechrome them but my restore guy gave me a warning that the material of which the handles are made is not really suited for this.
They are made from Zamac (or Zamak) which is a mixture of tin, lead and copper which could be casted at a relatively low temperature.
Over the years these materials reacted to eachother (electrolyse) which causes blisters and pitting.

It seems it doesn't matter how you prepare them or treat them, the blisters will keep popping up.

Is there a suitable sollution to this? Are there reproductions made from other material (not plastic )
We have a wild idea to scan them in 3D, make a mould and cast them in brass but that's quite costly...

Regards, Semjon

[Olivier]

Hi!

IMHO, if you have your original parts cleaned, and plated in the proper way, you should end up with like NOS handles good to go for the next 40 years...

Just google "zamak chrome plating" (I did) and you'll find tons of informations about it. Looks like there is a proper way to prepare zamak, for copper plating, then nickel then chrome which involves a lot of activating/passivating steps...

Just my 0.02€!

Olivier.

[Semjon]

Hi Olivier, thank you for your reply!
I indeed searched a lot and found indeed the process you describe. However many companies don't guarantee the outcome of the plating and warn about the blisters that can come back over time.
Since the whole preparation and chroming of the handles is also time consuming and costly with a non guaranteed outcome I'm searching for a good alternative.

[fourteenten]

Hi,

It's the same material as the two front horn grills and what I understood is that the deep pits are filled with solder (50/50, OR 60/40 ?) and then onto the plating process. Probably Alan of Canford Classics will be able to tell you more.

Rgds, Cees

[preS]

Is there a reason for you that you want to restore your 'original to the car' handles? If not, why not source a set of pit free handles?

Richard

[Semjon]

Cees, thanks for the tip! Will look into it.
Richard, since all the handles are made from zamac they all suffer this problem. Some have less pitting, some have more pitting but a perfect pair I haven't been able to source.
Thanks again!

[preS]

Cees, thanks for the tip! Will look into it.
Richard, since all the handles are made from zamac they all suffer this problem. Some have less pitting, some have more pitting but a perfect pair I haven't been able to source.
Thanks again!

Semjon, they are definitely out there. That is how I got mine. Try dry states like AZ and NV.


Richard

[Silverbullit]

I have my ('67) entire cars' worth of chrome at the platers now. They are in Oregon. I have seen their work on other Porsches and they sure seem to know what they are doing judging by their results. If interested I can post their info here on Tue (out of town). Brian

[chris_seven]

Zamak/Mazak - Zinc based die casting alloy.

mainly Zinc with additions of Aluminium, Magnesium and Copper.

Unhappily no Lead or Tin.

Soft Solders just don't work on Zinc based alloys as the contact angle of the molten solder is just to high and it won't wet the surface.

The problem with all die casting alloys is that they tend to be 'eutectic' compositions which means that they have a very short freezing range.

This helps with porosity and productivity but makes it very difficult to braze/weld this type of material as it goes from completely solid to completley liquid in about 5 degrees.

It may be possible to heavily Copper Electroplate and then re-polish but this tends to deal with relatively small pits and is quite expensive.

Yout could strip them, fill them with a metal loaded filler and vacuum metallise but they wouldn't be as durable as the originals.

[911scfanatic]

I have my ('67) entire cars' worth of chrome at the platers now. They are in Oregon. I have seen their work on other Porsches and they sure seem to know what they are doing judging by their results. If interested I can post their info here on Tue (out of town). Brian

Yes, please post info.