I've been getting out a bunch of postwar military/space surplus items to put on the bay. They're from about 1960 give or take a couple or three years.
What I have noticed, almost across the board, is that the flaps fall off the boxes by just looking at them. These trains have been stored in an attic in the temperate Pacific Northwest where it hardly ever freezes or gets above 90 degrees. It's hard to imagine that even though we get a lot of days of light rain it's actually not humid year round (in the attic, house or outside). So, I don't think that it's an environmental issue.
My prewar and early postwar boxes hold up a lot better.
I actually have to put a flap disclaimer in my listings saying that the boxes might look good in the listing pictures, but I cannot guarantee that they won't fall apart when they arrive and are handled (as they sometimes do). I have to tape a lot of flaps, and I disclose this in the listing.
Have others noticed this as well? They must have switched to some sort of cardstock that did not come with the 50 year guarantee like the chalking at the home improvement stores (how do they figure that out when sometimes the product is pretty new?).
Any thoughts?
Alan