[Elecraft] Re: Source of poor solder joints?

[Don Wilhelm]

Mark,

You are quite right in saying 'applying heat too long' is a problem.  It is
not high temperatures that cause problems but insufficiently high
temperatures applied for a longer time.  Components are designed to
withstand high soldering temperatures for a short time - they are designed
for wave soldering and other 'whole board' automated soldering techniques,
and component damage due to soldering heat is no longer a primary concern.

The way I check my soldering temperature is to see if I can make the solder
visibly flow in 2 to 3 seconds - if it does not flow in less than 3 seconds,
the iron is too cold, and if it flows in less than 2 seconds, the iron is
too hot.  My normal soldering temperature is 700 to 750 degrees for most
thru hole work and I use about 650 degrees for SMD work.  The actual
temperatur required will vary from board to board and it depends on the
copper area that is being heated.  Large areas of copper will conduct heat
away quickly and the iron temperature must be increased to compensate.

73,
Don W3FPR

> -----Original Message-----
>
> I agree with all Tom has stated, but to add a bit
> more(I didn't see mention of this), after cleaning the
> tip well I will dab just a touch of solder to the
> right before touching the joint to establish a
> "bridge."  This helps the transfer of heat quickly to
> the joint so that you're not applying heat too long to
> that high quality but fragile circuit board.  Too much
> heat for too long is a disaster to any pcb.  My $.02
>
> 73,
> Mark Baugh
> W5EZY