Re: [ATM] Polyurethane polishing pad

[Hugues.Laroche@ses-astra.com]

Hello Guy, Richard in he UK and all folks,

>Salem Distributing sells opthamological (?) polishing
>pads. Some mirror-makers use them to decrease the
>polishing time. They stick them directly on the
>fine-grinding tool, randomly, and polish with very
>small amounts of cerium oxide. 

I use such pads on a big 50% lap (22"). CeBrite II
from cantremember company.
I cannot really comment on the speed, since I did
not do twice the same job, once with and once w/o.
But one good thing mainly for slightly (or very much)
oversized work is that they have a lower drag than pitch
and it is much more consistent than a pitch tool not
totally mated. So it spares the arms or the pulleys
of the pusher. Actually it allows one to push laps that
would simply be impossible to move if in pitch
(I have pushed such a 30" tool by hand, hard but OK)
One piece of advice I discovered the hard way: to avoid
sleeks, do not forget to wet the pads a few minutes
before establishing contact.

Yes the polished surface is like a lemon peel. Mandatory
to finally smooth all this with pitch.

> In the UK, TrentMann Products do many poromeric
> polishing pads including alternatives to Politex, 
> Suba, etc. Left > menu bar from
> this URL :
>http://www.reliabletechniques.fsnet.co.uk/poromeric.html

I also tried this product, and it is unarguably best
for ATM purpose, even if not truly cheap. Pushing such
a lap is smooth like velvet, with a very good drag "feeling".
They can cut it to your tool size (up
to at least 25" if I remember well) and emboss is for
good slurry dispersion, for a modest increase of price.
(disclaimer blablabla, I am just happy with the service!).

Clear skies!

Hugues
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