Gibson A-1 in Classifieds -- from a time capsule?

[Bernie Daniel]

Fabulous looking 1917 Gibson A-1 (http://www.mandolincafe.com/ads/73299) in the Classifieds section. As note it probably has been in its case for many years. It's a beauty.

Look at the pickguard-- perfect! I think this kind of spikes the old off-gassing theory for pick guard degradation. I never have believed that idea anyway -- makes little sense from a chemistry perspective. Century old celluloid is probably not off gassing much.

[Jim Garber]

I am no chemist but I also have not seen much pick-guard degradation in teens and twenties mandolins. It seems to happen more in the later 1930s and 1940s. Wouldn't it be possible possible that the formulas for the celluloid had changed at some point?

[Bernie Daniel]

I am no chemist but I also have not seen much pick-guard degradation in teens and twenties mandolins. It seems to happen more in the later 1930s and 1940s. Wouldn't it be possible possible that the formulas for the celluloid had changed at some point?

I think I've seen a few from that period go bad. I had a 1919 F-2 with pick guard rot once.

As most probably realize that celluloid dates from the 1915 – 1920 era and as such is one of the very first synthetic plastics. Early celluloid was made by using camphor to catalyze a nitrocellulose polymerization reaction. It was a startling, almost miracle product in its day

Yes, the approach for making celluloid changed a lot and it the "early days" not all approaches to celluloid synthesis lead to stable plastics.

I expect that the degradation one sees with some vintage celluloid pick guards, albeit not in others, is due to inconsistency in the batch to batch synthesis -- i.e., poor quality control. Just making celluloid is very simple but it is more of a feat to make good celluloid and even today it is still a bit of an art as well as a science to make good celluloid.

I think less than ideal preparations of starting compounds e.g., nitrocellulose (level of nitration or purity) or even impure batches of camphor, or improper ratios of reactants, mixing and reaction times/temperatures of the synthesis probably lead to less than ideal/stable batches of plastics.

I expect some of these less well controlled batches resulted in the pieces that have degraded over time not any degassing process.

Camphor would be an especially likely suspect in my opinion. Camphor (a tree extract) a fascinating compound in its own right, has a 2-Bornanone ring system and thus is sterically-strained. Hence it is highly reactive due to the thermodynamically favored open chain form of the compound. Given the relatively crude methods for natural product chemistry it those days impure batches of camphor are easy to imagine.

Be interesting to see what other think of this but perhaps I high-jacked my own string by commenting on the pick guard. :)

[JeffD]

That is a beautiful mandolin. It is going to make someone vvvery happy!

[9lbShellhamer]

Goodness what a beauty!