M 1/72 Membership Pin

[Brig]

Here is my one and only non-photo HJ item...picked it up ten years or so ago at a small local show, it was in a bargain pin, I'm assuming because of the damage to the enamel. Can anyone tell my what caused the dark spots in it?

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[Wim Vangossum]

I think Jo once told me that it could be the result of bad cleaning before the applying of the enamel?


Regards, Wim

 

[Jo Rivett]

It is cracked, so condensation gets in and corrodes the base metal, creating what looks like black spots. You`ll find this normally around the edges of badges, as when it comes out of the oven and cools down, the enamel shrinks a fraction, ceating a thin line for condensation to seep in. But when it`s cracked like this, then the cracks offer gaps for this to happen.
Common to find. Here is a micro image of the "gap" around the letters on the GPB. Only a hairline gap, but enough for condensation and grime to get in - same thing when it`s cracked, worse even.
Funny, we were just talking about this exact thing a few weeks ago on the PA forum.
The yellow image is exactly this, a crack, letting in moisture, creating corrosion on the surface under the enamel, turning it "black".

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[Brig]

Thanks for the insight and images...I'm fairly new to enamel, not much of it on the USMC side of the house.

What is the PA forum?