Silvering/mirroring glass, any ideas?

To silver part of a standard mercury discharge lamp for use as a video
projector bulb, presumably less screen illumination , but 15 foot diagonal
not necessary.
No evacuation chamber available.
Ideas so far, aluminium cooking foil , cut to a ribbon, and wound around;
ground-off front and back of a photo-flood light bulb and fixed over as a
collar; any other ideas?


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Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/


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