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.
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.
- 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.