[Elecraft] KPA100 Tool question

[Ron D'Eau Claire]

 I have a good temperature controlled soldering station. What kind of
solder gun is require? I need to purchase a soldering gun for other
shack projects. I noticed Sears has 150/230, 100/140, and 100 watt
solder guns. Which one would be a good all around gun to have and would
work well for soldering the power transistors? Does it really matter?
Glenn WA7SPY

From what others have written, the soldering station MAY do the job. The
"problem" with soldering stations, or any "small" iron, is that unless
it can heat up the joint to get the solder to flow properly in a couple
of seconds, you are in danger of doing real damage to the PCB and
transistors. The guns are nice in that they have relatively small tips
but produce a lot of calories of heat to solder larger joints with the
proper speed to prevent damage. As others have pointed out, it is NOT an
issue with "temperature" as it is with heat energy. Trying to compensate
by turning up the temperature of a small-tipped iron is a dangerous
trick and likely to cause PCB damage AND bad solder joints. 

I have two Weller guns: a 100/140 and a 50-year old D550 that puts out
200 and 275 watts.

The big Weller was a great all-around tool in the 50's. I built a Viking
Ranger with it, along with a lot of other rigs. That much heat is not
good around most modern gear, though. About all it get used for today is
soldering big coax connectors (and I have to be careful not to overheat
the coax even so) and soldering up copper chassis panels. Yes, it will
solder 1/8 inch sheet copper panels just fine! 

The 100/140 is great for most jobs like big power transistors. It has
installed a lot of them in commercial mountaintop repeaters, etc. Many
manufacturers of those specified silver solder which needs some extra
heat. 

Nowadays I use my 100/140 watt gun on a lot of medium sized jobs, such
as the mic connector on the K2. It's also a LOT lighter than the bigger
gun. 

So if you were to buy ONE, I'd say the 100/140 unless you are thinking
of taking up plumbing. But when did we EVER have ENOUGH tools?

Ron AC7AC
K2 # 1289