[Elecraft] K2 and Low residue solder

Fri Feb 27 21:49:00 2004

Hi

I think we are getting a little carried away with this Multicore solder =
stuff. I have used Multicore and Kester 44 for over 25 years and I see =
very little difference in the quality of the joints, the flux residue or =
the ease of use. One core or five when the solder touches the heat it =
all becomes one core. Although it may make a slight difference to have =
five cores in a large diameter solder say .040 or .050, on the small =
stuff we use like .025 or .020 the difference is imperceptible.  The =
real difference is the solder to flux ratio. Most of the common =
electronic solders have a 3.3% flux ratio by weight. A higher flux ratio =
will leave more residue than a low flux ratio. Rosin is yellow and will =
show up on the circuit board if the solder has more than is needed to =
clean the joint. However for a novice assembler a solder with a little =
more flux will make the joints easier to make because of the better =
cleaning action. The low flux solder requires more skill because the =
flux burns off quickly so the heating of the joint and the method of =
applying the solder is more critical. I personally use Kester 63/37 .025 =
diameter solder with the 245 flux at 1.10% ratio by weight. This flux =
has a clear residue and is a low flux ratio solder. It leaves very =
little residue and what is left is almost invisible. It also cleans =
easier with alcohol than rosin. I would not recommend this for the =
novice. The novice should use 63/37 .025 or .020 rosin core solder like =
Multicore or Kester 44 or any other quality brand that similar with =
about 3% flux by weight. Solder with silver should not be used because =
it is more difficult to remove if a component must be replaced because =
of a mod, if it is defective or was accidentally installed in the wrong =
place. Silver solder is also more expensive (about 45% higher) and the =
joints may not look as good as the tin/lead joints even though they will =
work fine. The silver solder joints can have a dull look to them.

Don Brown
KD5NDB =20

----- Original Message -----=20
  From: James T. "Jim" Rogers<mailto:[email protected]>=20
  To: Elecraft Reflector<mailto:[email protected]>=20
  Sent: Friday, February 27, 2004 7:18 PM
  Subject: Re: [Elecraft] K2 and Low residue solder

  Well! Just for that I am going to take my "not Multicore" solder back =
to the
  basement shop and complete my KPA100 kit with my "not Multicore" =
solder. :-)
  I am sorry if I misled anyone, I asked for Multicore and was sold =
this....

  73 Jim, W4ATK
  K2 #4028

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