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Re: [ATM] ?Glued Mirror Cell

Richard,

The picture is really helpful.  I like the penny idea.  I was thinking of something like that, but the penny is easier.  What size/thickness did you make the flotation pivot?  Are you basically wetting the penny with the glue, then mating it with a larger blob on the bottom of the bar that, in my case, would already be glued to the mirror?

Thanks very much,

Rod
  ----- Original Message ----- 
  From: Richard Schwartz 
  To: Jan and Rod Shea 
  Sent: Sunday, September 12, 2004 10:11 PM
  Subject: Re: [ATM] ?Glued Mirror Cell




  Be sure to use a copper (pre-1982) penny, and just solder it onto a flat head brass 1/4-20 machine screw.

  I used a wood disk for the back of the telescope with and additional thickness of wood where the three holes are.   You MUST use a drill press to get the three primary holes straight.   I guess the picture above is self explanatory.

  Do clean the penny with detergent and water, then acetone, then a clean wipe.  Also degrease your finger with acetone, then use your finger to smear a thin film of silicone onto the penny to serve as a foundation for the thicker blob that will be the flotation pivot.


  ----- Original Message ----- 
  From: "Jan and Rod Shea" <jnrshea@comcast.net>
  To: <atm@atmlist.net>
  Sent: Sunday, September 12, 2004 4:15 PM
  Subject: [ATM] ?Glued Mirror Cell


  I am designing what I hope to be a very portable lightweight 12.5" dob, likely made from aluminum.  I'm willing to bite the bullet and glue the mirror to the cell, and make a compliant hinge cell using RTV.  I am thinking about a six point cell, PLOP derived, either Richard Schwartz right angle style or conventional.  Would simply RTV'ing bars to the tops of collimation bolts work, as long as the tops don't rotate when collimated, and I used very wide topped bolts (? ~ 1") or machine screws? Alternatively, some type of bearing could connect the glue pad and the collimation bolt, but that kinda defeats the purpose...  Seems like the glue should be GE type 840, about 1" in diameter, and 1/8" thick.  Has anyone made a cell like this?  Can someone point me to pictures?

  Thanks,

  Rod
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