[ATM] Gluing mirrors - was Coulter secondary adhesive

["Chris Dalla Piazza" <dalchri@hotmail.com>]

I might as well bring it up while we are on the subject...

I plan on gluing both my primary and secondary mirrors.  The secondary will
be attached to a Protostar support and the 6.5" primary to a 6061 aluminum
mount.

I was planning on using small shirt buttons as spacers and using spots of
silicon.  The reason for gluing the primary is to avoid mirror shift in this
fast f/4.5 system for more stable collimation.

For the primary, I was wondering what the suggestions would be for the size
and number of the silicon spots or if there is a better approach.  My
thinking is that the silicon will be flexible enough to absorb the stress
from the thermal expansion of the aluminum yet using 9 or more small spots
will create a stiff enough bond to keep the mirror in place.

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
Jarvis Krumbein
Sent: Monday, May 14, 2007 10:45 AM
To: lopez@mv.mv.com
Cc: atm@atmlist.net
Subject: Re: [ATM] Coulter secondary adhesive

The adhesive on the secondary of my Coulter 13.1" was very thin and very
hard after many years.  I used a razor blade to work between the glass
and the secondary.  When it was apart, it looked like the  glue was a
rubbery adhesive such as "Pliobond" which had gotten very hard with the
elapse of time.  Yes, it did warp the secondary which was the reason I
took it apart.  The astigmatism was completely cured be re gluing using a
silicon rubber adhesive (RTV).

Jarvis Krumbein

on Sun, 13 May 2007 23:11:42 -0400 "Lawrence D. Lopez" <lopez@mv.mv.com>
writes:
> A friend of mine wants to put what I choose
> to call a fancy heater on his secondary.
> It has 9 volt battery and tries to keep the
> secondary slightly warmer than free air.
> 
> At any rate he has a 17.5 coulter mirror
> set from a Coulter OEM tube.
> 
> The secondary has a very wide 3 inch or so
> single element spider and has a bent piece
> of 3" metal glued to the secondary.
> It's apparently painted flat black.
> 
> My friend want to remove the secondary
> from the "holder" to which it is glued.
> 
> Does anyone know what the glue might be ?
> He thinks it is epoxy but I would have expected
> that to deform the secondary.
> 
> Any ideas on how to remove the secondary ?
> 
> It barely possible that this was redone by someone
> other than Coulter.
> 
> Larry
> 
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> 
> 
 
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