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Thin vacuum mirrors
Great minds think alike??!!
On a similar vein, I've been dabbling with vacuum forming of thin ( 3mm) glass mirrors, you don't need a lot of vacuum.... (The original Mylar trial NBG, the surface just doesn't have the accuracy for an astro mirror)....
Couldn't get below about 2- 2.5m sagitta before " BANG", so soon figured out that the blank would have to be pre-slumped to say 5mm then held on a vacuum frame. The vacuum pulls the shape into a perfect parabola. Peerless Glass here in Melbourne are keen to help ( Can't find thin Pryrex sheet yet, any ideas?) So I'm meeting with then today to look at the manufacture of stainless steel moulds. Working with nominal 18" disks.
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