[ATMoB-discuss] Eyepiece repair

[Michael Brown]

In the environmental toxicology field (related to my work as an 
environmental consultant), trichloroethylene (TCE) is generally considered 
the worst of the common solvents, as a possible human carcinogen.  It is not 
an ozone depleting substance, but the related compound 1,1,1-trichloroethane 
is, and it was therefore banned although it is probably less toxic to humans 
than TCE.  This ironically caused some manufacturers to increase the use of 
TCE.  Acetone is considered fairly innocuous (very  high dose needed to 
cause any health effects), but is hazardous because of the flammability.

Mike

----- Original Message ----- 
From: <valleli at rcn.com>
To: <glenn at entropian.com>; "'ATMOB-discuss'" <atmob-discuss at atmob.org>
Sent: Monday, January 29, 2007 10:38 AM
Subject: RE: [ATMoB-discuss] Eyepiece repair


> Glenn,
> I should have CC:'d the discuss group because I answered that directly to 
> Ross. At Axsys we have been able to eliminated most solvents for lens 
> cleaning except Acetone and IsoPropyl Alcohol.
> Both are strong water absorbers but will weaken with exposure to the 
> atmosphere. We still have to use Toluene or the Opti-Clear Citrus 
> equivalent to dissolve polishing pitch efficiently. For a little bit of 
> pitch on the hands, DL waterless hand cleaner works well. Wearing rubber 
> or nitrile gloves could minimize skin exposure.
> My history of experience was with dozens of solvents, all bad news for 
> one's health. The most effective was Trichloroethylene - just figures it 
> would burn up the ozone!
>
> Acetone is in the family of Ketones that are normally in the blood stream 
> as a by-product of the consumption of body fat. That is therefore my first 
> choice.
>
> Beware that most alcohols available over the counter contain considerable 
> water. IsoPropyl Alcohol has an ability to dissolve both grease and oil 
> products and also many airborne contaminents such as saliva, aerosols, 
> spit marks, and water stains.
> However, I find it harder to get a residue-free surface compared to 
> acetone.
>
> Mirrors that have been exposed outside to a variety of airborne 
> contaminants usually require preliminary cleaning by immersion in purified 
> liquid detergent( Liquid Ivory - NO PERFUMES,NO DYES) then alternating 
> water/alcohol/acetone.
>
> Paul
>
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