Friday, February 5, 2010

Now That’s What I Call Shelf-Life



 I have rarely had cause to need gold paint. I have always fancied doing that gold-painted F-16, Sioux City Special I believe she was called, I even have a kit and decals lined up for the day I have the time... The chance... Somewhere to put it... But the odd gold detail might call for having gold in stock. I have a tinlet of Humbrol #16, Gold. I recently needed to open it for a few dabs of gold to visually blend in some gold foil I was applying, and sure enough, there it was, in the box at the back of the drawer. I really don’t remember if it was ever opened to do a job, but I am sure it was bought to do the gold detail work (engine accents, IIRC) on a small kit of the Honda CB 1100R motorcycle, by a firm called Crown. I bought that kit around Christmas 1982, it may be the oldest single article in my stash (still unbuilt). And by default, that means the paint is now around 27 years old. (The pic above is a new tin, I can’t seem to lay my hands on the old classic…) It wasn’t even thick in the tin. I gave it a shake, opened it and stirred it for thirty seconds, and it was good to go. When that paint was manufactured, that expression wasn’t even in use, nor were in the pipeline, 24/7, on track or my bad. That’s what you call shelf-life! Maybe the pigments weren’t as finely ground in those days, and the available ranges were smaller, but the chemical balance of the paint in the tin makes for a virtual time-capsule: so long as the balance remains within certain margins the mixture should remain viable forever. Of course, there are other tins that go hard while you look at them, and I had a bottle of MM enamel whose contents turned into a strange, rubbery substance without ever being opened, or maybe only for a tinting dab, but this is where chemistry meets philosophy. The same thing happened recently to another bottle, much newer, something to do with failure of the foiled card seal in the cap, I think. Folks have been complaining on other forums about this and other shortcomings of the Model Master range, lately, which is a pity as it’s really good paint, just let down at times by packaging issues (and accuracy issues, like the identification numbers of the RLM 82 and RLM 83 shades somehow getting reversed when the labels were printed… Or their Dunkelgelb being a bit on the dark side…) For the moment, I’m very impressed with Humbrol. Of course, the delicate balance of chemistry in the tin has been disturbed now, and the next time I look at it, it may have congealed, disintegrating like a vampyre whose coffin was opened before dusk. I guess we’ll see when it comes time to build that F-16 (unless I’ve graduated to Talon Acrylics by then...)

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