[pure-silver] Re: Weird Film Issue - Part II
- From: titrisol <titrisol@xxxxxxxxx>
- To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
- Date: Tue, 15 May 2012 20:57:08 +0100 (BST)
Most chemicals can kill you, even hydrogen hydroxide
use common sense and caution, do not drink any chemical and dilute them well
before/while dumping
>________________________________
> From: Jean-David Beyer <jeandavid8@xxxxxxxxxxx>
>To: pure-silver@xxxxxxxxxxxxx
>Sent: Thursday, 10 May 2012, 21:27
>Subject: [pure-silver] Re: Weird Film Issue - Part II
>
>Richard Knoppow wrote:
>> ----- Original Message ----- From: "Nicholas O. Lindan"
>> <nolindan@xxxxxxxxxxxxx> To: <pure-silver@xxxxxxxxxxxxx> Sent:
>> Thursday, May 10, 2012 10:24 AM Subject: [pure-silver] Re: Weird Film
>> Issue - Part II
>>
>>
>>> Photoflo 600 is the 'industrial' version. It has 3x the
>>> concentration of Triton and uses ethylene glycol rather than
>>> propylene. It will suds-up just like PF200.
>>>
>>> If there were to be an anti-foaming agent I'd lay odds it would be
>>> good ole' Dimethylpolysiloxane.
>>>
>>> I add PF directly to a bottle of isopropyl alcohol. 13ml of PF600
>>> to a quart of 70% isopropyl gives a stock that gets diluted 1:7 for
>>> use (1oz per 35mm film reel).
>>>
>>>
>>> Nicholas O. Lindan Cleveland Engineering Design, LLC Cleveland,
>>> Ohio 44121
>>>
>> A little research shows that there is a considerable difference in
>> the toxicity of propylene and ethylene glycol. Propylene glycol is
>> relatively non-toxic and is used in food and cosmetic products. That
>> may be why Kodak chose it for a product aimed mostly at home
>> darkrooms. Ethylene glycol is moderately toxic, one article points
>> out that is danger is from its sweet taste which may lead children to
>> ingest it. Both are used as anti-freeze and as wetting agents and
>> humectants. I don't know how to tell the relative effectiveness.
>> Kodak chose the ethylene for the industrial form of Photo-Flo but the
>> reason is obscure to me. Perhaps cost or effectiveness. Someone
>> with more chemical knowledge than I can perhaps explain. The other
>> ingredient of both kinds of Photo-Flo appears to be Triton-X 100, AKA
>> a bunch of chemical names, a non-ionic surfactant. There are also
>> several other products sold under the Triton-X name, see:
>> http://www.dow.com/surfactants/products/octyl.htm
>>
>>
>I have only a residue of knowledge from high school chemistry and a
>little bit from chemistry 5.01 and 5.02. Namely not much.
>
>I do know that propylene glycol costs more than ethylene glycol.
>Ethylene glycol is used in automotive cooling systems to reduce freezing
>point (and raise boiling point). In this use, the chances of
>contaminating a home water supply is negligible.
>
>The main use I know of for using propylene glycol is in home heating
>systems using forced circulation of hot water. In such systems there is
>an anti-backflow valve to keep water from the heating system from
>getting back into the domestic water supply. The connection between the
>two is to allow makeup water to be added to the system to replace
>leakage. Since those valves can fail in time, the codes normally do not
>allow toxic additives to be added to the boiler water. So ethylene
>glycol is out, but propylene glycol is used as anti-freeze.
>
>
>--
> .~. Jean-David Beyer Registered Linux User 85642.
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