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     Steve_s Tinkerer Username: Steve_s Post Number: 123 Registered: 07-2006 Rating: N/A |
I must admit I hadn't heard of tin pest! Self-destructing zinc alloy definitely can be a problem with cameras and lenses, though, Glenn. I have one of the original type Braun Paxettes which is disintegrating from this cause. A few weeks ago I stripped an Enna Sockel auto mount. I was surprised to find that the helical guides were zinc alloy diecastings and both of them were badly cracked. Fortunately one of them still had just enough strength to hold things together. The other one fell to bits as I was using it as a pattern to make a steel replacement. Not all zinc alloy die-castings seem to suffer from the problem, but I don't know whether this is due to different types of alloy, different casting technique, or different environment. The material used to be known as "pot metal" in the US, but it is also known by several much less polite terms on both sides of the Atlantic! |