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- To: owner-atm@shore.net
- Subject: BOUNCE atm@shore.net: Non-member submission from [mark wilkinson <laseroptics@compuserve.com>]
- From: owner-atm@shore.net
- Date: Wed, 19 Feb 1997 10:30:32 -0500 (EST)
>From atm-owner Wed Feb 19 10:30:23 1997 Received: from dub-img-5.compuserve.com (dub-img-5.compuserve.com [149.174.206.135]) by relay1.shore.net (8.8.3/8.8.3) with SMTP id KAA29998 for <atm@shore.net>; Wed, 19 Feb 1997 10:30:22 -0500 (EST) Received: by dub-img-5.compuserve.com (8.6.10/5.950515) id KAA03427; Wed, 19 Feb 1997 10:29:45 -0500 Date: Wed, 19 Feb 1997 10:29:10 -0500 From: mark wilkinson <laseroptics@compuserve.com> Subject: RE: ATM Speculum metal for mirror making To: Chris Westland <westland@uxmail.ust.hk> Cc: re atm silvering <atm@shore.net> Message-ID: <199702191029_MC2-1178-5C63@compuserve.com> I attended a conference in london about 4 years ago, entitled metal mirrors for astronomy, it was held at the University college london. The general agreement was aluminium of suitable grade and heat treatment was a good candidate as a substrate but since aluminium is near impossible to get any sort of finish on electroless nickel was proposed as a coating. This could be polished and then coated further. My company make small eg 6 inch laser mirrors just like this Electroless nickel is difficult to deposit on Aluminium and hard to get fault free though. If any body can help with this off topic aspect I would be very grateful. One idea that I think will happen is to make a series of mirror segments from aluminium and electron beam weld them into a large mirror. it seems e beam welding is totally free of distortion, or so the Uk's welding institute's presentation claimed. I anticipate the next message on this topic will be about beryllium. This is a great metal mechanically strong and light but the dust is very very toxic and exposure is strictly regulated and enforced by our Health and Safety authority. Mark wilkinson laseroptics@compuserve.com
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