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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: net.analog
Subject: Re: Re: Re: Rosin flux hard to find?
Message-ID: <680@kitty.UUCP>
Date: Thu, 2-Jan-86 10:16:48 EST
Article-I.D.: kitty.680
Posted: Thu Jan  2 10:16:48 1986
Date-Received: Sat, 4-Jan-86 07:10:26 EST
References: <789@brl-tgr.ARPA> <652@kitty.UUCP> <218@ski.UUCP>
Distribution: net
Organization: Recognition Research Corp., Clarence, NY
Lines: 63

> > 	Because the market demand is extremely low.  If you really insist upon
> > having rosin flux, you might wish to consider the small containers of rosin
> > flux which are sold for plumbing use.
> 
> I don't know where this fellow shops, but as far as I know, plumbers ALWAYS
> use acid fluxes.  These include liquids or pastes with zinc chloride as the
> active component- it yields hydrochloric acid.

	I was ONLY referring to a product labeled as: ``Rosin Flux''.  This
does NOT include ``Soldering Paste'' - which is in fact a mixture of rosin and
zinc chloride.  I presume that anyone wishing to buy rosin flux knows how to
read!
	Two retail repackagers of solders and fluxes for hobby and home
repair use are Oatey and Plumbcraft; the materials which the above companies
repackage include solders and fluxes for electrical and other use. 

> I have NEVER seen rosin flux in plumbing stores.

	Pure rosin flux is often used in refrigeration work for sweat soldering
of small diameter copper tubing and fittings, where the presence of excess acid
flux on the interior of the fitting can be particularly harmful.

> If you use acid flux on your electronic circuits, you can kiss them goodbye.

	It might surprise you to learn that the above generalization is WRONG!
I would suggest that you look at a catalog from one of the major electronic
solder manufacturers - like Kester, Ersin, or Gardiner.  You will discover
that MANY rosin fluxes are in fact ``activated'' fluxes and contain chemicals
(such as chlorides) which are in fact ACID in nature.
	I quote from the description of two Kester products:
Kester 2400 - "An organic, chloride-type, very stable flux for reflow soldering
	       on circuit boards..."
Kester 2410 - "An organic acid flux, free from choride, for reflow soldering on
	       on circuit boards..."
	Many rosin-core solders contain MORE THAN just rosin as the flux.  For
example, a solder sold exclusively for electronic use such as Ersin Standard
Alloy Multicore (tm) solder is available in three grades: "R" - which is pure
rosin core; "RA" and "RMA" which contain an acid type activator.
	Rosin by itself will not flux satisfactorily when certain types of
oxidation are present on the connection surfaces; as a result, further chemical
additives are required.
	Good and proper soldering practice - whether in production environments
or in casual hand soldering - dictates the REMOVAL OF EXCESS FLUX remaining
after the soldering operation is complete. There are a variety of flux removers
on the market, and this is what they are for!  In a production environment,
soldered circuit boards have excess flux removed through a washing or vapor
cleaning operation; in a hand solderimg operation, excess flux can be removed
using a small brush dipped in flux remover.  Incidently, a safe and generally
effective flux remover is iso-propyl alcohol - which can be obtained at low
cost from a hardware store or pharmacy (don't get rubbing alcohol, however!).
	As long as proper removal of excess flux is carried out, then the
use of fluxes containing acid is not at all contraindicated for electronic use.
	IMPORTANT NOTE: I am NOT advocating the indiscriminate use of acid
fluxes (like sold for plumbing use) on electronic circuits!  I am merely
establishing the point that acid fluxes ARE used on electronic equipment under
certain conditions.

==>  Larry Lippman @ Recognition Research Corp., Clarence, New York        <==
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