[Elecraft] Soldering and Heat Damage ?

[Jack Smith]

Robert Pease, in "Troubleshooting Analog Circuits" (p. 82) provides a 
useful anecdote on the subject of modern silicon semiconductors and 
soldering iron heat:

    ...Overheating does not by itself cause failure. I once applied a
    soldering iron to a 3-terminal voltage regulator--I hung it from the
    tip of a soldering iron and then ran off to answer the phone. When I
    came back the next day, I discovered the TO3 package was still quite
    hot-- +300C, which is normally recommended for only 10 seconds. When
    I cooled it off, the regular ran fine and met spec. So, the old
    dictum that high temperature will necessarily degrade reliability is
    not always true. Still, it's a good practice to not get your power
    transistors that hot, and to have a base drive that call pull the
    base OFF if they do get hot.


Pease also offers the following comment in discussing equipment 
necessary in any well equipped lab (p. 23):

    A suitable hot soldering iron. If you have to solder or unsolder
    heavy busses from broad PC-board traces, use a big enough iron or
    gun. For small and delicate traces around ICs, a small tip is
    essential. And, be sure the iron is hot enough. An easy way to
    delaminate a trace or pad, whether you want it or not, is to heat it
    for too long a time, which might happen if your iron weren't big
    enough or hot  enough. (The old Heathkit warning not to use a hot
    iron became obsolete along with the germanium transistor.) In some
    cases, a grounded soldering iron is required; in others a portable
    (ungrounded or rechargeable) soldering iron is ideal. Make sure you
    know whether your iron is grounded or floating.

Bob Pease should need no introduction, but for those not familiar with 
him, a good starting point is http://www.national.com/rap/

Jack K8ZOA
www.cliftonlaboratories.com