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Cleaning optics with polymer lens cleaner, what about liquid masking film?

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33 replies to this topic

#26 gregj888

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Posted 12 July 2018 - 02:46 PM

Being  is a dangerous endeavor.   Who else would put 25 kg on a 2 axis holder and spin it with motors... in the dark?  Only saving grace is it doesn't spin real fast undecided.gif

 

Common sense an some understanding of the laws of physics (and chemistry) also help...

 

Stay safe...

 

BTW, is #7 the primer?



#27 bmwscopeguy  Happy Birthday!

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Posted 12 July 2018 - 03:18 PM

Hi Greg,

 

Wow - a Trischiespiegler. Did you make it yourself? I've always been fascinated but I know myself well enough to know I wouldn't have the patience.

 

And yes, we are both of a generation (I'm presuming here) where we were a lot more incautious for our own safety, which was more often than not tempered with common sense, an understanding of the process, and an appreciation of the consequences if you failed.

 

Although I don't have it on my sign off - I currently have in my stable.

 

6" Celestron SCT on Evolution mount

4" Televue Genesis

6" Russian TAL F5 Newtonian reflector

and hopefully soon - a 3.5 Questar. (quite possibly the same one I sold to agent late last year...)

 

I also know where there is a clapped out Questar 7" OTA and I'm talking with the guy - He's not into astronomy or telescopes but he has found out just enough to know it's worth something. So it's like getting a crow to give up a shiny bauble....lol

 

Stay tuned.

Malcolm



#28 gregj888

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Posted 12 July 2018 - 04:08 PM

Malcolm,

 

Yes, I did the optics for all the listed scopes.  I also have an 8" meade SCT that's been converted from quartz to a 2 axis OnStep system. 

 

Also had a TR3, MGB and MGB-GT plus a number of other needy vehicles until moving to newer stock.  Wish I still had the TR...

 

The Tri isn't all that hard to make.  The primary does have very soft corrections, took me 3 tries.  Final was by count, something like 11 "W" strokes... The tertiary has a really long ROC, bear to align the tester, unless you put a laser pointer on the tester, then take longer to walk the 45' than to align. 

 

Very nice views of the planets, with good seeing able to see the festoons in the bands of Jupiter.  The Tri is my primary star party scope, lots of fun.



#29 Oregon-raybender

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Posted 13 July 2018 - 01:01 AM

Being a Safety Officer for several large optical companies, I cared for my fellow employee. I wanted them to go home to their families. We choose to remove chemicals that were not worth the effort, expense, that did not work and/or had safety concerns. Sorry, I was not over acting, but offering my professional suggestion to fellow CNs to keep them safe. If you want to take the risk using this material, that's your decision. But many of CNs are looking for good advice because they do not have it. I think it's important that we who have the knowledge of limits of these materials, need to speak up. The method of using a film to clean optics has been around for decades, it is a good solution. But I would spend $100 to know I will be safe than $5 to be sent to ER. I knew Bob, and many others like him, friends in the industry. My experience and training helped me be a better safety officer and made many changes inside the companies I worked for.  Be safe out theregramps.gif

 

Starry Nights waytogo.gif


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#30 Bruce Kizerian

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Posted 13 July 2018 - 09:51 AM

Being a Safety Officer for several large optical companies, I cared for my fellow employee. I wanted them to go home to their families. We choose to remove chemicals that were not worth the effort, expense, that did not work and/or had safety concerns. Sorry, I was not over acting, but offering my professional suggestion to fellow CNs to keep them safe. If you want to take the risk using this material, that's your decision. But many of CNs are looking for good advice because they do not have it. I think it's important that we who have the knowledge of limits of these materials, need to speak up. The method of using a film to clean optics has been around for decades, it is a good solution. But I would spend $100 to know I will be safe than $5 to be sent to ER. I knew Bob, and many others like him, friends in the industry. My experience and training helped me be a better safety officer and made many changes inside the companies I worked for.  Be safe out theregramps.gif

 

Starry Nights waytogo.gif

Thanks for writing this. Regular reminders help me not to be so casual when using chemicals and materials in my home workshop. It's good to re-read the cautions on the containers once in a while. I've also learned to slow down and take the time to use chemicals properly.



#31 Eikonal

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Posted 14 July 2018 - 09:52 AM

Professionals stopped using colloidal based materials decades ago, do to the chemicals used and the learning curve. It was not cost effective or worth the risk and health of our employees or the optics. We saw no reason to use it, because simple cleaning methods and materials are available that work better.

But I like the smell of ether in the evening. wink.gif

 

Seriously, I have been using pharmaceutical grade collodion for a couple of years now to clean ruled gratings and plane mirrors, but it takes quite a frew tries to understand how to get the tickness of the layer right, so that the shrinkage of the film makes it curl up when drying. If you get it just right, the stuff pretty much peels itself off.

 

And it is very hard to achieve this on curved surfaces.

 

Collodion comes in a variety of preparations, with different contents of guncotton.

The one I can buy in German pharmacies accorcing to German medical regulations is 4% nitrocellulose, dissolved in ether.

This makes for a quick evaporation, but again, you can only work with it under a fume hood or in very well ventilated conditions.

Ether (chemically di-ethyl ether) makes you drowsy or even pass out when it reaches a certain concentration in the air. 

I have had this happen to me, once: A student left a number of used cotton swabs with ether on them in a glass dish in a lab cupboard. I opened the cupboard and basically fell flat on my face. Needless to say, I gave that particular student an appropriately hard kick up his posterior the next day!

Also, if diethyl ether fumes make up more than 1.7 % of a room's air, the fumes may explode at the slightest provocation (a spark from a light switch may very well suffice).

And, as a last point, store it below 25°C (77°F), because the pressure in the bottle rises rapidly if warmed beyond this point. I have known ether bottles in labs to explode if left out in the sun on a hot day. That's why I keep my collodion in the fridge and let it warm to room temperature when I need it.

 

The reason why I am still using collodion is two-fold: I have studied chemistry (among other things), and I am quite comfortable working with dodgy substances. The other is: I simply cannot afford to buy the expensive stuff marketed as optics cleaning film.

 

As always:

- Use the extremest of cautions to the best of your knowledge.

- Alway know what you are doing.

- Do not blame others if something goes wrong because you did not inform yourself properly.

- But in the first place: If you feel insecure about this (be honest!), it is better not to use collodion!


Edited by Eikonal, 14 July 2018 - 10:17 AM.


#32 don clement

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Posted 14 July 2018 - 01:31 PM

 

 

 The other is: I simply cannot afford to buy the expensive stuff marketed as optics cleaning film.

 

 

Exactly!



#33 MiguelStrongEye

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Posted 14 July 2018 - 02:25 PM

Well, as long as someone brought it up...

The scariest thing I’ve ever worked around is hydroflouric acid.

Not only is it corrosive it will dissolve your bones from the inside.

It can stop your heart by interfering with the nerves.

The fumes walk right through most masks and PPE.

If you have to work with it keep this stuff around and don’t work alone.

https://www.amazon.c...g/dp/B008YGHVOK

 

Do NOT underestimate that hazard.

 

High concentration ammonia is also pretty nasty.

Anhydrous will flat knock you down then explode in the wrong concentrations, but it’s a great refrigerant and steel hardener so it’s common.

Even the high concentration solution used in blueprints can be a threat in an enclosed space.

 

Partially used blueprint solution is a fantastic window cleaner...Windex with nothing but distilled water and ammonia.

So I suppose this post Is on topic after all.


Edited by MiguelStrongEye, 14 July 2018 - 02:36 PM.


#34 don clement

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Posted 14 July 2018 - 03:38 PM

When I worked at the GaAs foundry there kick out panels in the clean room in case of an HF leak. We were instructed to run like hell in case of an HF leak. https://www.youtube....h?v=4Uf_rTLqj0o


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