Date:         Mon, 11 Apr 2005 08:39:11 -0400
Reply-To:     Agent99 <email99@BELLSOUTH.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Agent99 <email99@BELLSOUTH.NET>
Subject:      Re: pH meters for around the shop
Content-Type: text/plain; charset=us-ascii; format=flowed

pH Indicator paper is a good alternative to a pH meter and is much more
reliable and accurate for occasional use.  It also has a tremendous
price advantage over a meter.  pH meters require calibration to be
accurate and the electrodes are sensitive to abusive treatment, such as
use in non aqueous solutions or high salt solutions.  Accurate pH
measurement of an oil is a questionable concept since pH is defined as
-log[H3O+] in aqueous solution.  You can, however, get a rough idea of
acidity of an oil by wetting a piece of pH indicator paper with water
and dipping it into the oil.  A standard pH electrode will change values
as the oil clogs the junctions and it will fail rapidly if not treated
correctly and cleaned properly after each use.

pH indicator  paper or dip strips are available in full range (pH 1 to
14) and also short range (spanning 2 pH units) from any chemical supply
house such as FisherScientific although you might have a problem
ordering from these places.  You might also find pH paper at your local
pharmacy,  pool supply, aquarium supply or maybe educational supply stores.



>> so i have been wanting a pH meter for measuring different fluids around
>> the shop such as salt solutions, coolant, possibly oil, and various other
>> pet projects.  i don't want to spend a ton of money on one