Welcome Keith to the Society! I am the current ACGHS newsletter editor and also retired sharing my passion for all things Gilbert with my Son and my Granddaughter (She loves to build things).
Regarding telling the difference between Zinc, Cadmium and Nickel parts. Not very scientific but I can usually tell by the color, feel and yes, smell of them. For example, I’ve notice Nickel parts tend to have a yellow cast to them. However, I will see if I can find a more scientific process for determining that.
Seems to me this topic would be great for a newsletter article.
The 50th Anniversary Special set from Sears was produced in 1959. I have 2 of them in my collection as they are one of my favorites. (It’s been said I say that about all my sets.)
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Best regards,
Michael D. Foster