I would like to caution newcomers and first time builders on the "turning
the knob" on your
new adjustable soldering station (e.g. Pace, Haako, Weller, Metcal) to
achieve more heat.
There are actually THREE factors at work to have the proper amount of heat
transferred to
a joint for soldering (or removal of enamel from a wire)
FIRST step is the heat setting on your solder station that is achieved by
turning a temperature knob, selecting a "Thermolock" key or a specific
temperature determined by the tip. This is the obvious step that everyone
uses, and then forget the next two steps!
SECOND step is actually more important, matching the type of joint to the
profile of your iron's tip. This IS the step that is routinely missed or
forgotten when soldering a kit with multiple joint types (e.g. surface
mount, through leads on PC board, or external connectors).
The normal iron tip profiles that are available are: screwdriver; single
flat and conical. The length (normal at .60" and long length at 1.0" ) is
another variable for density and location of the solder joint. I prefer
screwdriver for through hole and single flat for wire stripping and some
external connectors (e.g. switches)
THIRD step is the size (mass) of that tip's profile. These vary from less
than 1/32" to 1/4" or greater. For example, I am building W8ZR's current
kit - its front panel assembly requires installing numerous toggle switches,
dual row connection strips, resistors and LEDs.
The issue for this particular assembly was not heat, but rather the varying
mass of these soldering connections. For the resistors and LEDs, I used my
standard 1/16" tip at 700 degrees (PTA7) with .020 solder. HOWEVER, for
soldering the toggle switches, I changed to a 3/32" or 1/8" tip (PTB7 or
PTC7)and .031 solder staying at 700 degrees. My "dwell tip" on the joint
and soldering technique stayed the same.
--------------
This problem of assembly technique is NOT unique to Elecraft builders or new
soldering users. When I toured the 3Com Ethernet NIC assembly plant eight
years ago, they were having quality problems with the external connectors
(e.g. BNC, RJ-45 [8-pin]) on their network cards being assembled by
automation. The cards were largely surface mount components being assembled
in about 10 seconds with normal surface mount assembly techniques. The
massive external connectors (in relation to the surface mount components)
received the most stress (outside world and end users) on the card and were
subject to marginal soldering joints would eventually fail. The problem was
traced to the fact that these connectors were not receiving sufficient heat
during the automated assembly process. Until the process was changed,
manual rework (human hand soldering) was required on these connectors to
assure a proper attachment/ connection to the board.
So, in summary, when you are faced with a complex PC board type -- you will
need to change your tips and maybe even the size of your solder -- no matter
what type of soldering station (knob adjustable or not) you are using.
"Then why is the knob on these adjustable soldering stations?"
That answer has more to do with the various solder formulations being used
today and new "no lead" solder formulations in response to no lead
requirements (2006) and initiatives in Japan and Europe.
Today's Tin / Lead formulations: eutectic 63/37 ratio at 361 F / 183 C or
the popular 60/40 ratio at 374 F / 190 C are easily handled with tip
temperatures in the 600 to 750 degree range.
The new "No Lead" formulations will require additional heat and MORE
attention to soldering techniques (example above).
Some of the "No Lead" solder formulations that are currently available with
higher melting temperatures are:
Tin, Silver and Cooper ratio of 96.5/3.0/0.5 with 423 F / 217 C melting
point or
Tin and Copper ratio of 99.3/0.7 with a 440 F/227 C melting point.
As you can see, this is a 65 to 80 degree difference -- and good soldering
techniques will be very important.
Greg
Message: 6
Date: Sat, 28 Aug 2004 07:24:47 -0700
From: David Katinsky <[EMAIL PROTECTED]>
Subject: Re: [Elecraft] Hakko 808 wanted
To: "Ron D'Eau Claire" <[EMAIL PROTECTED]>,
<[email protected]>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="US-ASCII"
I want to second the importance of using enough heat. Initially, I tried
to
remove the enamel at my soldering temp of 750 and it did work, but took
forever and was fairly frustrating. After deciding to move my temp up to
800
for this process, it was literally 5x faster and easier.
David N2RDT
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