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68312Re: Removing Flux - even further off topic

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  • rlramirez77
    Sep 3, 2012
      Just an FYI if anyone has difficulty using or obtaining alcohols for flux removal.

      I used to own a paint company and had to understand solubility and solvent chemistry quite well. Most store bought denatured alcohol will work the best because it is often denatured with small amounts of gasoline or toluene. Also quite common is 'recovery' solvent from use in the electronics industry where the solvent is blended into ethanol to denature it.

      In chemistry there is a phrase 'like dissolves like' because organic substances and their matching solvents are in the same chemical family. For example, aromatic hydrocarbon resins like rosin (which is a complex blend of molecules) are *best* dissolved by solvents that are also aromatic. Pure ethanol (200 proof) would not do a very good job if you could try it. In fact, the shellac resin still sold today sometimes is extended with rosin and will not dissolve in alcohol, but remains in suspension at the bottom of a container. Hexane (used in some contact cleaners) is actually an aliphatic hydrocarbon, but still is a bit closer to what would ideally dissolve colophony resin (rosin), which would be substances like turpentine or xylene. Solders like Kester 44 still use rosin in case you wondered.

      I hope this was at least interesting.


      --- In softrock40@yahoogroups.com, Keith Carter <kcarter49@...> wrote:
      > I worked for the USMC in the Metrology division in the early "80's. All
      > the circuit boards that we manufactured were cleaned with denatured
      > alcohol routinely. Must have been known to cause no long term problems
      > because we soaked boards in the stuff.
      > KF4BI
      > On 9/2/2012 4:15 PM, Jerry Kaidor wrote:
      > >
      > > > Apparently the strong kind is not available in California.
      > > *** Um, I think it is. I'll go down and check my can....
      > > The description reads:
      > >
      > > Denatured Alcohol
      > > High grade fuel for alcohol burning chafing dishes and marine stoves.
      > >
      > > Sounds like the strong kind to me. Bought it at the local house paint
      > > store.
      > >
      > > - Jerry, KF6VB
      > >
      > >
      > >
      > > No virus found in this message.
      > > Checked by AVG - www.avg.com <http://www.avg.com>
      > > Version: 2012.0.2197 / Virus Database: 2437/5245 - Release Date: 09/03/12
      > >
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