[Harp-L] Re: Propolene Glycol

[BluzeHarp@xxxxxxx]

'hygroscopic' is correct.  When the AC and refrigeration industries  
stopped using the ozone destroying CFC and HCFC based refrigerants they also had  
to stop using mineral oils in those systems, as they were  not compatible 
with the new classes of refrigerants.  The new PAG  oils they use are very 
similar to the mentioned PG oil, and are also  extremely hygroscopic, so much 
so that traditional plastic containers were  abandoned in favor of metal 
ones, due to concerns of moisture being  sucked from the atmosphere right 
through the less dense molecular structure of  the plastic and contaminating the 
oil! 
 
The standard effective method of removing excess moisture from mineral  oil 
based refrigeration systems was to pull a deep vacuum on the system for  1 
- 3 days, mineral oil slowly releases moisture under these conditions,  PAG 
(and probably PG) oil does not, it does not easily let go and  thus seems a 
good choice for use on your slides.
 
What the PG oil would seem to be doing is absorbing and  capturing the 
moisture from the slide, as mentioned these oils do not  easily give up this 
moisture to be re-deposited on the slide over  time.  Once the oil reaches it's 
maximum saturation point your  saliva will again begin to dry on the slide 
and cause sticking, but the  lubricating qualities of the PG oil may help to 
reduce the effect even when  fully saturated.  
 
However... PG oil is likely to leave a film, however slight, that  could 
capture solid particulates.  These particles have the  potential to cause 
accelerated wear.  So, if you have rare or very  expensive instruments you might 
want to weigh the potential wear factor against  the increased playing time 
between cleanings.
 
Search Amazon for Propylene Glycol, lots of options in various sizes  will 
pop up.  Note the spelling of 'Propylene'.  Be sure to stay with  items 
rated as food safe or designated for musical instrument use.
 
Christopher Richards
_www.harmonicaplanet.com_ (http://www.harmonicaplanet.com) 
Staging & Production - SPAH
 
 
 
In a message dated 11/10/2014 5:33:48 P.M. Mountain Standard Time,  
harp-l-request@xxxxxxxxxx writes:

Yesterday I posted about using Propolene Glycol as a slide  lubricant.  I
incorrectly stated that it was  "hydrophobic".   Quite the opposite, it is
"hygroscopic" meaning  it attracts water and will even pull water out of
humid air.   I  have no idea how that might affect its utility as a  slide
lubricant.   All I know is that it seems to work pretty  well.