Posted 2015-04-12 10:41 AM (#475184 - in reply to #475175) Subject: Re: 1930's F0rD purple headlights
Location: Under the X in Texas
What is the point? A lot of early headlamp glass cast in part-lead molds tended to turn purple when exposed to the sunlight for years. Time was in this hobby it was a very common sight at swap meets --- back when parts for teens and twenties cars were still on tables at swap meets. Houseware glass of the era and earlier similarly turned purple and we've seen those antiques.
Posted 2015-05-13 2:37 AM (#478123 - in reply to #475225) Subject: Re: 1930's F0rD purple headlights
Location: Parts Unknown
I am always looking for Model T lenses in a good, strong purple.
These are marked with the Ford script and the letter "H" and were used
from 1918 to 1927.
It was the manganese, used as a de-colorizing agent, that caused the
amethyst coloration after exposure the the sun's UV rays. The greater the
chemical imbalance toward manganese, the darker the purple. It seems
Ford's (and other mfr's) suppliers for lenses used a variety of decolorizing
agents - some purpled, some did not. Selinium causes a more yellow-orange
"straw" color change, and this is also seen.
My only interest in Ford vehicles are black-era Model T trucks (1917-1927),
to which these purpled headlight lenses are appropriate. Those in the ad here
are 1930-31 Model A headlights. Whole different critter !