Re: Care of Rare Valves
I think glass flowing is a myth. I have used (although don't own) an astronomical refracting telescope with an objective lens over 150 years old. I have (and use) camera lenses of half that age. The optical performance would be ruined if the glass had flowed at all. And the effects noticed in 80 year old valves would seem to be a lot larger than the amount of flow to ruin a lens of a similar age.
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