You guys got it all wrong...Crystals don't fog. I was told it is a "crystal patina".
Maybe the plastic attracts more moisture than metal?They can stick the patina where the sun doesn't shine. These companies aren't stupid and I'm sure they have items in stock they have seen themselves with crystal patina. I wouldn't be shocked if they have an idea for the reasons. I see all kinds of theories, but throughout most forums they majority suggest it comes from moisture in watches that are sealed poorly. Although that may be true in some circumstances, all of mine have been safely stored with moisture packets and never exposed to any extreme temperature changes so I'll stick with the out-gassing theory of cheap plastic materials. The movement retainer, dials and parts of quartz movements puts many different plastic parts in just one watch, not to mention the rubber gasket for the case back.
Maybe the plastic attracts more moisture than metal?
That plastic casement theory is a bust. I just took apart my Automatic Sea hunter and there wasn't any plastic anything inside of it and it still had a foggy crystal. well its clean now. Im still not sure what the deal is with the fog.
ut when they pull out the crown to change the time or date, air and moisture could possibly enter.If they have a certain WR rating with screwed down crowns and are BNIB never exposed to the environment how could moisture or anything externally get inside to mix with the culprits? It was only conjecture, but I still think something is going on internally from the materials mentioned. If I was a scientist with his own lab I would be able to have a definitive answer, but unfortunately it's all hypothetical.
I believe the lume sandwich dial is on a plastic disk and the crystal itself has a plastic gasket which you can see looking through your dial. As mentioned by RW and others earlier....plastic outgassing is only ONE of the reasons behind the inner crystal fog.
I'll take wiser Wyts word for it. I definitely don't know, just speculating. I do know this though, I would rather clean a foggy crystal once every 10 years or so than have to change out batteries every other month.
ut when they pull out the crown to change the time or date, air and moisture could possibly enter.
LOL .... ten years is one thing, but some of the watches are only a few years old if that. I haven't even been collecting for ten years or so myself.
I have no horse in this race, but an observation...if all the watches that fog up are under $300 (for example) , and NO watches over $600 (for example) ever fog up, just consider in the cheaper priced watches, a fogged crystal will occur. Use the dollar savings to pay for a crystal cleaning. Or, if that bothers you, only buy more costly watches that don't fog.