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<DIV>Hi Rob</DIV>
<DIV> </DIV>
<DIV>I use a rosin based solder and prefer not to leave any flux on a PC
board post assembly. Rosin flux is only active at high temperatures but the
residues can cause problems in the long term if the board is left in a damp
environment.</DIV>
<DIV> </DIV>
<DIV>I clean my homebrew PC boards with alcohol, cellulose thinners or similar
(extreme care is needed here with polystyrene based components), dry them and
then cover the solder side with a clear polyurethane varnish for long term
protection. Commercial PCBs can have a solder resist that does the same function
as the varnish but should still be cleaned of flux residues.</DIV>
<DIV> </DIV>
<DIV>I would never consider using a liquid flux on a PCB but see the next
paragraph.</DIV>
<DIV> </DIV>
<DIV>Plumbers flux is very useful for tinning badly corroded parts
contacts but MUST be completely removed before final assembly or the
residue will cause severe oxidation of any metal parts. You only have to look at
a copper water pipe left with flux residue a year later to see the growth
of a green oxide.</DIV>
<DIV> </DIV>
<DIV><FONT lang=0 size=2 face=Arial FAMILY="SANSSERIF"
PTSIZE="10">73<BR></FONT><FONT lang=0 color=#0000ff size=4 face=Arial
FAMILY="SANSSERIF" PTSIZE="14"><I><BR>Bob</FONT><FONT lang=0 color=#000000
size=2 face=Arial FAMILY="SANSSERIF" PTSIZE="10"></I><BR>Bob F Burns G3OOU,
G-QRP 6907, @BobFBurns<BR>Crystal Palace Radio & Electronics Club: <A
href="http://www.g3oou.co.uk/">www.g3oou.co.uk</A><BR>Technical web site: <A
href="http://www.qsl.net/g3oou">www.qsl.net/g3oou
<DIV> </DIV>
<DIV>
<DIV>In a message dated 08/09/2015 18:49:13 GMT Standard Time,
rsmyers@rogers.com writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>OT
question on soldering since it looks like I may soon be doing a bit more<BR>of
that than usual.<BR><BR>I see No Clean Flux liquid for sale at a local
electronics shop. It sounds<BR>better than flux where cleaning is
required, but I see Rosin Flux for sale<BR>right beside it, so there must be
some trade off.<BR><BR>Is there much of a difference?<BR><BR>Thanks,<BR>--
Rob<BR><BR>_______________________________________________<BR>Heath mailing
list<BR>Heath@puck.nether.net<BR>https://puck.nether.net/mailman/listinfo/heath<BR></FONT></BLOCKQUOTE></DIV></A></FONT></DIV></FONT></BODY></HTML>