[ATM] Blocking parts for Polishing

[Alfredo Neves]

Hi Scott,

Yeah! In the book "Fabrication Method for Precision Optics" they talk about
the UV cement specially made for blocking. Thanks for the tip on Universal
Photonics. I will contact then and try to get the UV stuff. 

Regards,

Alfredo


-----Original Message-----
From: Scott Milligan [mailto:starzkey at charter.net] 
Sent: Wednesday, September 24, 2008 6:43 PM
To: 'Alfredo Neves'; atm at atmlist.net
Subject: RE: [ATM] Blocking parts for Polishing

One way is to use the single-part UV curing optical blocking agent that
Norland Products (and probably others, too) sells for this purpose.  The
stuff cures under longwave UV light, however the bond is weaker than a
typical UV cure optical cement, and can be dissolved in hot water when time
to deblock.

You might also contact Universal photonics in Hicksville NY and ask to speak
with one of their technical sales reps.  Universal sells many different
"stacking & blocking" waxes, each at one time formulated to solve specific
problems of the nature you report.  Finally, you might consider that your
blocking technique, rather than the materials used, may either be at fault
or else may contribute to failure.  A key parameter is probably the
thickness of whatever agent is used, with less giving greater positional
stability, but greater chance that blocking stresses may be too high.

Scott Milligan


-----Original Message-----
From: atm-bounces at atmlist.net [mailto:atm-bounces at atmlist.net] On Behalf Of
Alfredo Neves
Sent: Tuesday, September 23, 2008 8:34 PM
To: atm at atmlist.net
Subject: [ATM] Blocking parts for Polishing

Hi All,

I am currently trying my hand at producing a  lot of 10 diagonals. I blocked
the parts to a flat pyrex mirror blank with some "Blocking wax" I mixed up
from rosin and beewax. Unfortunately when I unblocked the diagonals they all
came out very astigmatic. I assume that my blocking  wax is the cause. I am
now temped to use pure pitch so that it flows better. Can anyone give me
some advice on the best way to set things up for stress free blocking. 

Regards,

Alfredo



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