[pure-silver] Re: Cleaning lenses
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 19 Apr 2006 14:00:18 -0400 (EDT)
> > From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-
> > bounce@xxxxxxxxxxxxx] On Behalf Of Ryuji Suzuki
> > Sent: dinsdag 18 april 2006 18:25
> >
> > Since someone mentioned this in another post... if isopropanol is used
> > alone as the cleaner, you'll have to wipe more number of times and
> > still see streaking. That's a common problem with highly volatile
> > cleaners. Alcohol solvent simply dilutes the grease a bit and spread
> > it back on the glass surface.
From: "Breukel, C. \(HKG\)" <C.Breukel@xxxxxxx>
Subject: [pure-silver] Cleaning lenses
Date: Wed, 19 Apr 2006 10:11:00 +0200
> Exactly my experience when I clean older lenses with isopropanol, it
> takes many "passes" to get rid of the grease.
>
> What would you advise as a better solution?
So the solution I described before....
My glass cleaner is this:
0.2 ml Triton X-200 (anionic surfactant)
2.0 ml 28% ammonia (or 20 ml household strength)
20 ml isopropanol, 90% (or 25 ml of 70%)
distilled (or otherwise mineral-free) water to make 100 ml
Usually, a part of the soil is water soluble, and the rest fatty
substance. It's best to blend a degreaser (ammonia),
detergent/dispersant (Triton X-200) and solvent (water/isopropanol).
In this type of cleaner, it's more important to transfer the soil to
the cloth rather than dissolving or decomposing the soil.
If X-200 has to be substituted with something else, whether
dishwashing detergent (for hand use) or PhotoFlo-type X-100 based
surfactant, it's less important than having three components in a
single solution.
Like I said, ammonia may be replaced with ethanolamine
(monoethanolamine) if ammonia is objectionable.
From: "Edward C. Zimmermann" <edz@xxxxxxx>
Subject: [pure-silver] Re: Cleaning lenses was: RE: Re: Cleaning picture frame
glass
Date: Wed, 19 Apr 2006 11:23:01 +0200
> Would not methanol or even, since one clearly is just dealing with
> glass (the ether would not do well with plastics), why not acetone?
> Ether is horribly volatile.
If the glass is washed in water-based cleaner first, these, as well as
alcohol-ether mix would work well, but routine cleaning of lense is
probably less effective if entirely nonpolar solvent system is used.
> There are probably better surfactants for this application but
> Agepon is cheap (I could get some good stuff from Kremer but I think
> it'd cost me more) and convienient and I always have some around---
> its really just a wetting agent plus sulfonic acid--- my guess is
> 2-phenylbenzimidazole-5-sulfonic acid to block UV-- some sodium
> salts and sodium benzoate (1-5%) [preservative].
Are you sure about this? Many effective anionic surfactants use
sulfonic acid as the hydrophilic part. Triton X-200 is one such
surfactant.
In 2-phenylbenzimidazole-5-sulfonic acid, the sulfonic acid is acting
as the solubilizing group. Without this group, such a compound would
be practically insoluble in water phase. But at the same time, I don't
know why AGFA would incorporate such a compound in final rinse bath.
> While on the topic of lens cleaning.. Just stuck me that it could
> make sense to "bake" one's optics from time to time in a
> transilluminator-- good strong UV-B but without the baking heat of
> sunlight. Make sense? Or just a stupid morning coffee idea? :-)
I think common optical glasses are relatively opaque to that
range. You might want to use gamma ray radiation instead. But then the
cloudiness in old lens surface is not necessarily fungus based, but
instead vapor given off from paints from inner surface of the barrel,
etc. This is Richard's area, not mine.
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