[Elecraft] Calibrate Solder Station

[Ron D'Eau Claire]

Hello Walter:

Having lived with (and without) solder stations for both Ham and
professional use for several decades, I've yet to see any value in
calibrating them for service and the sort of assembly work we do. 

The value in the temperature control is that it maintains a constant tip
temperature, whatever that may be. The actual temperature is determined by
how long it takes to melt solder using a tip size appropriate for the size
of the joint (although there's a LOT of leeway there - I only change tips
when going from a very tiny SMD to a very large connector). 

If your solder flows freely onto the joint in 3 or 4 seconds of you have the
right tip temperature, whatever it might be. That presumes decent heat
transfer using a tip that is "wet" with a film of solder and ensuring the
solder wire touches the hot iron and joint simultaneously so some solder and
its flux flows onto the joint to clean the surfaces. (With tiny pads such as
for SMDs, I generally put a tiny drop of flux on the pad instead of melting
solder to avoid overloading the pad. A *little* goes a *long* way, with
either solder or flux, especially on small joints.)

One of the biggest mistakes is to set a temperature, such as 700F, and leave
it there, no matter how long it takes to melt solder. Parts are injured just
as quickly (perhaps faster) by an iron that's too cool requiring too long on
the joint as with an iron that's too hot. "Roasting" traces or parts for too
long is very hard on them. 

My current solder station is a Hakko 936 that has been in heavy use for a
decade and I see no difference in the amount of heat it delivers. I like
that it has a simple knob temperature control.

99% of my soldering is done with the tip at 750F (400C) and the temp is
increased to about 800F (425C) when cleaning a joint with solder braid. 

I tend to get a lot of life out of my tips because I turn it off when it's
not being used. After all, it takes less than 30 seconds to come up to full
temperature. Even so, one time I noticed my dwell time was too long to get
solder to melt at my "usual" temperature setting so I disassembled the tip
and found lots of corrosion had collected on tip/heater interface. A little
cleaning and all was FB again. 

Ron AC7AC



-----Original Message-----

Greetings,
 
I'm going to purchase a solder station, probably one of the popular Weller
or Hakko units, with additional tips.  Both manufacturers sell accessories
to calibrate the stations.  Some recommend performing a temp calibration
whenever you replace the tip or the iron.  All well and good until you see
the cost of these calibration (test) units.  Would it be prudent to forego
the calibrations altogether, and just swap tips as needed, and rely on the
initial cal to keep it in the ballpark?  I'm guessing after getting used to
the station, you will have a sense of proper temp for a particular job, and
could just tweak the temp setting up or down as needed without really
getting into the calibration arena.  Just wanted to see what folks thought
about calibration and if it was worth it.  Thanks.  73
 
Walter, WB2IDK (ex-N0DZJ)