Re: [ATM] no to beeswax!

[Guy Brandenburg <gfbrandenburg@yahoo.com>]

I have no experience with black rouge, but I find that
ordinary red rouge makes the final stages of figuring
easier to control and gives a considerably smoother
(less rough) surface. The difference in smoothness is
dramatic when you look at the ronchi test. I also like
tempered burgundy piitch. 
Cerium oxide is great for just plain flat-out
polishing. If your lap is too hard, adding a small
amount of beeswax to the molten scrapings will make it
a bit softer, mbut it is easy to make it much too
soft. But if it does get too soft, you can simply put
it back on the heat and let it bubble away for a few
quarters of an hour, and it will harden up somewhat.
There are deep dark secrets in most professional
opticians' pitch mixtures. I've heard some of them
accompany them into their coffins .... No, I just made
that up. But: notice, Gugolz doesn't really tell you
what's in their pitch, do they now?

Guy
--- Bill Marriott <bmarriott@pacbell.net> wrote:

> Hello,
> 
> A couple of comments here.  First off, black rouge
> is not something I 
> would reccomend using to generate a polished surface
> off a ground 
> mirror.   Black rouge either does not work at all,
> or just as a final 
> final figureing compound, depending on who you talk
> to, and all will 
> say, what a MESS it will make.
> 
> A better appraoch would be to find out why pitch and
> cerium did not work 
> for you.  After an hour of work, you should have a
> start of a polished 
> surfce, and in another 6-8 hours mostly done. If you
> are getting 
> scratches, its becase of contamination of your pitch
> or polishing 
> compound. If just haze, then you have a way to go,
> and there might even 
> be pitting from a previous grit that was not removed
> by smaller grit 
> size aluminum oxide.
> 
> Nothing beats Gugloz Pitch #64 and CeO for
> generating a great mirror 
> surface.(IMO)  Let us know more....
> 
> Bill Marriott
> VA Optical Labs
> 
> 
> Jon Bales wrote:
> 
> > Here's a miserable failure story. 
> > I'm polishing an 8" f5.7 mirror.  Using pitch and
> CeO, I couldn't get a surface that didn't show some
> light scattering at the surface using a cheap red
> laser.  (there were comments about lasers
> previously). Otherwise the polish looked good. 
> Having learned that rouge gives a better polish, I
> ordered some, and coated the tool with beeswax
> before using the black rouge.  That's the failure
> story.  Beeswax leaves brushmarks that will not
> flatten out even after warming the tool and warm
> pressing.  The pitch will soften under the wax, and
> give,  before the beeswax flattens out.  I think
> I've learned not to use beeswax.  Now I see that Tex
> calls beeswax a rigid material which doesn't deform,
> and leaves defects.
> > 
> > Now a question.  What is the best substrate to use
> with black rouge?  There are several pitch varieties
> offered.
> > _______________________________________________
> > ATM mailing list http://www.atmlist.net/
> > 
> 
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> 


=====
Guy  Brandenburg
Washington, DC
My home page:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
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