Mike Knudsen wrote:
I just received the following from a friend who has been building electronic
circuits for his home pipe organ (talk about boat anchors). He got shorts in a
solid state circuit, so imagine what the new solder he describes would do in
high-impedance tube gear!

It works fine.

The new organic fluxes are basically the same thing as the old acid flux
materials, just more soluble.

They can be removed with a water wash rather than with toxic solvents,
but they MUST be removed. If you do not deflux, they will corrode and
destroy the electronics.

A standard household dishwasher will work for defluxing boards.

Now I discover that the flux residue on the new spool is CONDUCTIVE! It's easy
to discern the difference between the old and the new: the earlier "rosin"
material was yellowish and hard, and when you picked at the edges of it, it
would break off in hard granules. The new residue is clear and soft, about the
consistency of ear wax. (The label on the spool says that the flux is
"Organic," so perhaps it *is* ear wax.)

Tell your friend to read the data sheet on the solder next time before
buying it. The Kester data sheets have all sorts of warnings about
this and about the importance of defluxing.

These are very popular for mass production applications, because they can
be defluxed very easily. This is a big win for high-Z circuits. But you
must deflux.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."