[ATM] tde hypothesis

[David Harbour]

For Mel, Peter, and all:

To reply to Mel's rhetorical question, down below a little ways, why did I 
always (almost always) get TUE? Was the late Bob Goff's explanation right?

It had to be that fan, cooling the edge of the mirror, sloppy with Cerium 
oxide slurry. D'ya s'pose?

R-101

P.S. To the very best of my knowledge, I am the only person to have made 
even one telescope mirror (let alone the dozens that I did actually make) in 
this city, a town of 50,000 people. (?!?!?)


----- Original Message ----- 
From: "Peter De Baan" <pdebaan at hotmail.com>
To: "Mel Bartels" <mbartels at bbastrodesigns.com>; <atm at atmlist.net>
Sent: Sunday, June 08, 2008 3:52 PM
Subject: Re: [ATM] tde hypothesis



I suppose Mel's pitch laps are 1/2" or more oversize which made avoiding TDE
Next question is how to make the over size lap when pouring it on the mirror 
?

Peter
> From: mbartels at bbastrodesigns.com> To: atm at atmlist.net> Date: Sun, 8 Jun 
> 2008 11:01:59 -0700> Subject: Re: [ATM] tde hypothesis> > Consider:> > * 
> Press pitch persistently but gently and it yields. Hammer pitch and it> 
> shatters.> > * Solid tool with polishing pads: more or less TDE?> > * Our 
> mentors from the past used felt, sometimes cloth polishers. Their> reports 
> of TDE: same, different, and why?> > * Carefully measure the diameter of 
> the pitch in contact. Those with TDE of> 1/4 inch may be surprised to find 
> that their contact pitch diameter is 1/4> inch less than the mirror. What 
> does that mean?> > * Pressing harder or softer while polishing - which 
> tends to cause TDE?> > * Why do some suffer from TDE and others never 
> catch it?> > > Mel Bartels> > 
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