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Testing NOS Elliptical

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#1 JohnH

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Posted 07 December 2019 - 09:06 AM

I found some ferric chloride solution, so I am good to go with cleaning the coating of an 8" Diane Lucas flat to make it useable for uncoated optics.


I have a seconday that while old, 25 years or so, is in good shape so I want to test it without sripping the coat.


I guess that Rayleigh water test is the best way

Edited by JohnH, 07 December 2019 - 09:07 AM.


#2 Pinbout

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Posted 07 December 2019 - 09:22 AM

I test coated flats with uncoated masters all the time.

 

a lot easier than the water test.

 

just use a fluorescent light bounced off a sheet of white foamcore onto the flats.

 

need monocolor, observe looking thru a red gel.

 

basically how I do it on my messy table

 

https://www.youtube....45PT43k&index=3

 

 

a coated flat

https://www.youtube....45PT43k&index=4

 

a red gel over the cell phone

https://www.youtube....5PT43k&index=14


Edited by Pinbout, 07 December 2019 - 09:28 AM.


#3 JohnH

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Posted 07 December 2019 - 11:34 AM

I was expecting a bright green solution not a darkish brown one for the ferric chloride. What gives?

#4 dan_h

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Posted 07 December 2019 - 11:39 AM

I was expecting a bright green solution not a darkish brown one for the ferric chloride. What gives?

I worked in electronics all my life. I've only known ferric chloride to be brownish in color. Never green.

 

dan



#5 Dale Eason

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Posted 07 December 2019 - 11:41 AM

IIRC All the Ferric chloride I ever used was dark brown.  Current bottle is as well.



#6 JohnH

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Posted 07 December 2019 - 12:41 PM

S***.


The 3.5 inch one coating mark goes into the surface.

1/4 inch long.


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