Re: [ATM] Stuck 20" lap on 30" mirror

["Scott Milligan" <starzkey@charter.net>]

Dry ice, nice touch.  Even better, next time, you will skip the first step,
eh?

Shared by one who has stuck a full-sized 32" lap to a $10,000.00 substrate
and lived to tell the tale.

Scott Milligan

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
Lawrence Sayre
Sent: Friday, November 02, 2007 1:08 PM
To: ATM List
Subject: Re: [ATM] Stuck 20" lap on 30" mirror

Ouch!  Glad to hear that it came undone.   Hope the resulting fit is a 
good one!!!

Larry Sayre

Bill Prewitt wrote:
> I've been traveling a lot lately, and have only been able to work on 
> this figuring project for a few days every month or so. Last month, I 
> poured a fresh layer of Gugolz 55 on a 20" lap, and left it to cold 
> press till I came back.
>
> Big mistake... It was stuck tight.
>
> To dislodge the lap, I tried bar clamps, tubular webbing with a wood 
> lever, then plastic-sheathed steel cable with a metal lever for several 
> days of sustained force, but nothing worked.
>
> So yesterday I bought 10 pounds of dry ice, layered it on top of the 
> lap, and covered everything with towels and blankets. After 24 hours of 
> chilling under tension, the lap separated easily from the mirror.
>
> The lap surface was shiny & black.
> I had forgotten to coat the face with CeO before pressing.
>
>       Bill Prewitt
> ----------------------------------------
>           www.astrocaver.com
>   webpage of telescope making and caving
>       My hobbies keep me in the dark
> ----------------------------------------
>
>
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
>
>   

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