I've never heard of Bromothymol blue being used as a residual flux
indicator, but it certainly still exist.
Most chemical suppliers have it in stock, it's a regular acid-base
indicator.

It is yellow below a pH of 6.0 and blue above 7.6. (In between, it depends
on other conditions, any colour between yellow and blue).

Hope this helps,

Alain Savard, B.Sc.
Chemical Process Analyst
CAE Electronics Ltd.
e-mail: [log in to unmask]


-----Original Message-----
From: Glenn Pelkey
Subject: [TN] Residual Flux Indicator

Hi all,

        Anyone familiar with a dye that can help indicate the presence of
residual flux?  I was just talking with another engineer who mentioned a
material called "Bromthymol Blue" that he used to use.  Is it still
available
or is there's something better?

Glenn

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