Back to Home

ATM Forum Message

Forums: Atm · Astrophotography · Blackholes · Blackholes2 · CCD · Celestron · Domes · Education
Eyepieces · Meade · Misc. · God and Science · SETI · Software · UFO · XEphem
RSS Button

Home | Discussion Forums | Amateur Telescope Making | Post
Login

Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...
The Space and Astronomy Agora
RE: RE: Aluminizing Mirrors.....

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Frank O'Shannassy on July 29, 2000 18:15:46 UTC

High vacuum equipment is fussy stuff. I built a home aluminizing vacuum system in the late 1950s, large enough for my 12.5inch mirror. You need a steel baseplate, ground flat, a molecular (langmuir-type or other) pump backed by a roughing (rotary) vacum pump. You also need a bell jar (Pyrex, thick wall) with a neoprene gasket. Also, you can make a reasonably good pressure indicator by runnng high-voltage intot he chaber. When you get a plasma keep pmping until the plasma goes out, then you rare getting close tot he vacum needed to aluminize. Typically, you hang pure aluminum wire on a tungste coil ad boil it off with low voltage hi amp current. You can make a step-down transformer.

Old Al coatings can be removed usig lye solution (sodium hydroxide)

If you want to make this stuff yourself, first read the chapter in Strong`s then try to find some books on vacuum technology that were printed in the 1950s or `60s. That technology is suitable for the amateur vacuum builder.

High vacuum is fun, but very difficult to work with - design and cleanliness is absolutely important.

Good luck!

Frank

Follow Ups:

    Login to Post
    Additional Information
    Google
     
    Web www.astronomy.net
    DayNightLine
    About Astronomy Net | Advertise on Astronomy Net | Contact & Comments | Privacy Policy
    Unless otherwise specified, web site content Copyright 1994-2021 John Huggins All Rights Reserved
    Forum posts are Copyright their authors as specified in the heading above the post.
    "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET"
    are trademarks of John Huggins