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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: ? ? ? Re: Doug Royer's Artificial Horizon
From: Bill B
Date: 2005 Feb 25, 16:53 -0500
From: Bill B
Date: 2005 Feb 25, 16:53 -0500
> If I am not mistaken, what is called "float glass" is cast on top of a > liquid, so it is extremely flat except at the edges. The trick with > the steel would be finishing it flat to the same degree. Don't know > what they do to flatten Plexiglas, how it is cast. Molten zinc I am told. My source claims almost all domestic glass is float glass these days, as opposed to calendared. A long while ago I had to specify float glass to get a flat piece for lapping plane bottoms, chisel backs etc. While I was aware plexy can be very thick, did not know they made mirrored that thick. Live and learn. Bill
