Re: RE: ATM polishing

[<tomjan@ozemail.com.au>]

If this is his first mirror I'd suggest using a slightly under sized lap, maybe 1/4" undersized. Two reasons real simple to press, and you don't have to worry about whether you pressed it right or not, if you don't press an oversized lap the right way you WILL get a turned edge, but an undersized lap will only give you a turned edge if your polishing technique is wrong.

For a first mirror KISS really applies.

Just my $0.02

Thomas.
www.tjanstrom.com  
> 
> From: "CSC" <optic@gwi.net>
> Subject: RE: ATM polishing
> Date: 09/12/2002 15:35:26
> To: "Atm" <atm@shore.net>
> 
> 
> 
> Clean up the shop. Do long polishing spells...turn the radio on, get
> comfortable and do it. The fewer times you leave the work and return, the
> fewer scratches.
> 
> Use plenty of pressure and a fairly thin slurry once the mirror "beds in".
> Don't let the grooves close up.  They should stay open for ~3 hours if the
> pitch is about right. If they close up in an hour, the pitch is a bit too
> soft or the room too warm.
> 
> Using a 1/2" oversize lap makes for a nice edge, but requires extra care
> when first pressing/starting polishing. You need to keep the mirror moving
> over the edge when pressing. Then gradually increase the pressure when
> beginning polishing.  After a few minutes, it will be set and you can polish
> as usual.  It's a hassle unless you are going to polish for 3 hours straight
> or use a machine.
> 
> Polish completely before testing.
> 
> Colin
> 
> -----Original Message-----
> From: owner-atm@shore.net [mailto:owner-atm@shore.net]On Behalf Of Tommy
> Sander
> Sent: Friday, December 06, 2002 10:44 PM
> To: Mail List
> Subject: ATM polishing
> 
> 
> 
> "i am just about ready to start polishing my 6" pyrex mirror. Does anyone
> have any cautions or tips for polishing. And what are some excellent sources
> on polishing. Thank you.
> 
> 						Tom
> 
> 
> 
> 
> 
> 

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