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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Restoration
From: Brad Morris
Date: 2018 Sep 23, 11:10 -0400
From: Brad Morris
Date: 2018 Sep 23, 11:10 -0400
Hello Bill
In the case of sextants which are approximately more than 75 years old, I would not recommend replacing the mirror glass.
Consider the case of a 1700's octant. Would you replace the mirrors with modern glass? Likely no, as the antique nature of the artifact argues strongly against that.
Move into the 1800's and the argument still holds up well. The object's integrity, it's sum of the parts, argues for resilvering of mirrors.
It's only when we move into the 1900's that the argument becomes more tenuous. Sextants made since the dawn of the GPS age arguably are modern and unless the restorer is particularly fastidious, no argument can be made regards the sanctity of the artifact.
Which leaves me, in my opinion, at or about the 75 year mark. I'd like to see sextants, of a certain age, retain their components. That those components be restored to their former glory.
The ease of just plopping in a new mirror is very convenient. I understand that you mean that it is unnecessary to resilver. That doesn't preclude resilvering where warranted. I think you mean that too.
Brad
On Sun, Sep 23, 2018, 12:39 AM Bill Morris <NoReply_Morris@fer3.com> wrote:
Frank
It is nowadays unnecessary to re-silver mirrors, as the float glass from which modern mirror glas is made is flat enough over small areas to do the job. Rectangular mirrors are easy to do oneself, while circular ones need a little more effort. Learn how to do it here: https://sextantbook.com/category/new-sextant-mirrors-for-old/
Bill Morris
Pukenui
New Zealand
