Re: RoHS

[Geert Jan de Groot-3]

It's not just a matter of using different solder.

The new solders have a higher melting point and hence need a hotter
soldering iron; typical 50W WECP/WTCP won't do because, while they
have the temperature, they lack capacity at those high temperature -
they can't heat the joint quickly enough.
You'll need the newer 80W soldering stations or risk cold joints.
There's a reason the older 50W stations are available so cheaply
these days.

The new soldering iron comes with a tip that has a thicker ironized coat
as the new solders corrode tips a lot faster.

Forget about using a wet sponge. Because of the higher temperature,
wiping on a wet sponge would cause too big a temperature jump
and hence you'll need to wipe on a special tool.
Note that the routine differs: wipe, wet, solder, wipe, wet,
back to holder.

The new tools together cost about half a K2.
Note that it's important not to contaminate your RoHS-tools with
your older tools: small pieces of lead will change the
composition of the alloy, greatly reducing reliability.

The higher melting temperature means that un-doing a component
is more difficult, with a higher chance of PCB damage,
certainly with less experienced builders (not everyone has
a space qualification, I don't).

Because the new solder's wetting characteristics are a lot worse,
I'm concerned about stripping and wetting toroids with lead-free
solder.
Wel all know that not everybody is fully successful wetting and
stripping toroids as-is. Just ask Gary, who, I'm sure, is not looking
forward to higher warranty claim percentages because of doubtful
toroid stripping with lead-free solders.

Note that some new alloys have a tendency to form bridges (shorts)
after a number of years. Not a problem for a toy that gets discarded
after 2 years, but big problem for a tranceiver which typically
has a lifetime of 20-30 years.

We all see the cheerful messages from people who "haven't soldered
in over 20 years" or so, and are now getting back to kitting.
Lead-free soldering is a lot less forgiving to new, but unexperienced
builders as it is intended to be used in tightly controlled circumstances.
(we all know that with a WTCP and leaded solder it's difficult to
"go wrong").

While I realize that it's less environmentally friendly, I think
that using leaded solder, for a large percentage of
the building population, will have enough advantages that we should
make use of the exception to the rules that was given to us "kit-ters".

I agree with Elecraft that the change should not be made lightly,
and not just by using different solder. They suffer the consequences
of a lower yield percentage, and I don't think anyone would want that.

73,

Geert Jan PE1HZG
K2#1981, not RoHS-compliant, sorry!

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