New Dimensions in Digital Sound Technology
SoundTraxx Guide to Successful Soldering
A crucial element to most sound system installations is
the ability to make a good solder joint! Unfortunately,
many modelers think they know how to solder and can
do a great deal of damage before someone sets them on
the right path.
Safety First
As you prepare for soldering, there are several safety
considerations that you should be aware of.
n When you finish soldering, unplug the iron so it
will be cool when you want to clean up and put it
away. Leaving a soldering iron plugged in once
you are done using it invites forgetfulness. A hot
iron can start fires and can burn curious fingers.
n Most solder contains a high percentage of lead.
Dispose of used solder and desoldering braid.
Keep all solder substances out of the reach of
children and pets. It is also a good idea to get in
the habit of washing your hands after handling
n Secure the item to be worked on, i.e., put the
circuit board on a stable work surface or in a
vise – don’t try soldering on your lap!
Choose the right tools
We recommend a fine-tipped, 25W soldering iron
and rosin core solder for use with any SoundTraxx
sound system. A temperature-controlled iron is a great
Flux is your friend
Electronic solder is made as a tube, with the rosin (flux)
in the tube. Things that get hot tend to oxidize. Metal
will oxidize quickly when heated to the 700-degree F
temperature required to melt solder and solder will not
adhere to oxidized metal. Solder will also rapidly oxidize
while molten. Once solder has oxidized, it does not melt
and flow, but resembles a paste instead.
There are many different types of flux available
separately to accomplish specific jobs. Brass modelbuilding, jewelry work or plumbing tasks all utilize a
different type of flux that can be damaging to delicate PC
board work. Be sure to get the flux that is designed for
electronic PC board work.
When applied to a hot solder connection, flux first flows
over the work and tip, then begins to burn, normally
without flame. As the flux burns, or oxidizes, it removes
Soldering Reference
oxygen from the metal as well as the air in contact with
the connection. This allows the solder to lock into the
molecules of the metal, rather than resting on the oxide
Some liquid solder flux for desoldering and some flux
remover are also handy.
Six Steps to Successful Soldering
1. Plug in the iron and rest it in its holder (If your
soldering iron does not have a holder, make
one from something that will not burn, but
preferably not metal, such as ceramic tile. If the
tip or barrel come in contact with metal, the iron
will not get as hot as it should as quickly as it
2. When the iron is hot, wipe the tip on a
dampened sponge, then tin the tip with a small
amount of solder. A metal tray is handy to flick
the excess solder into.
3. Heat the work, not the solder, by dabbing a bit
of solder on the tip at the point where the tip
touches the work, as it touches the work – this
is a two-handed operation! This helps to heat
the part quickly so that the solder will flow nicely.
Then shift the solder to the part and flow it in.
4. Let the work cool for a few seconds.
5. Examine your work. The solder should be
smooth and shiny, not dull and gray. It should
look more like a smear, not a puddle. Where a
wire enters solder, the solder should taper up to
the wire. There should not be a doughnut hole
full of flux.
6. Clean up the board with flux remover and a
cotton swab. Use wooden rather than plastic
swabs as the flux remover may melt some
plastic materials.
Using Heat Sinks on Delicate Components
Most components are designed to withstand the
sustained heat of wave soldering circuit boards.
However, if you are unsure, or if the parts are really,
really expensive, you might want to use a heat sink on
the part while soldering.
A pair of hemostats, or even a stray alligator clip will
work well. Of course, you can also use your trusty
needle-nose pliers. Just keep whatever you use close
to the component, or you won’t be able to get the
connection hot enough.
Oops! Ok, so you used the wrong part, soldered in the
wrong place, or need to replace a broken part. This
requires desoldering. If you’ve never desoldered anything
before, practice makes perfect. Keep old projects and
circuit boards for practice pieces and as a source for
practice parts.
Usually heating the leads and pulling them out of the
board one at a time is good enough. A touch of solder
on the iron often helps, but parts with multiple leads or
legs can be tricky. This is where desoldering braid can
come in handy.
Desoldering braid is a copper braid with flux worked into
it (sometimes known as solder wick). Usually the braid
is placed on the connection with the iron then applied to
it. Often a touch of solder will help get things going. Once
enough solder is removed, you can often use a gentle
pressure with small pliers to loosen the lead. A touch of
liquid flux before heat is applied can also help.
Desoldering braid is also useful for removing solder from
the holes in a circuit board so that parts may be inserted.
This is common when replacing broken parts.
The Solder Sucker
Another useful desoldering device is the solder sucker.
Basically, a solder sucker is a syringe, with a spring
and a trigger. The plunger is depressed to the lock
position. A little fresh solder will provide flux to keep
things molten. The Teflon tip is then held in proximity
to the heated solder connection. When the trigger is
pressed, the spring pulls the plunger outward, causing a
vacuum, which inhales the molten solder. The plunger is
depressed again to the lock position and it’s ready to go
once more.
Every few hundred cycles, the unit should be
disassembled and cleaned. The seals should be
greased with silicone grease and the tip will occasionally
require replacement. Keep a spare around.
The solder sucker requires a bit of practice to nail down
your technique. Positioning of the tip and compensating
for the recoil of the spring are both important as is
deciding when the solder is just hot enough to flow well.
Liquid Solder Flux
Another useful tool when soldering and desoldering is
a little bottle of liquid solder flux. It may be available in
a little 1 oz. Bottle, with a brush in the lid, or in a 1-liter
bottle. If the latter, an empty, clean nail polish remover
bottle makes a good dispenser. Liquid solder flux lets
you cheat on one important aspect of soldering.
For example, tinning a wire requires holding the wire,
the iron and the solder. A brush of flux on the wire will
allow you to tin it with a blob of solder hanging from the
iron, thus freeing up that third hand. The results are
It can also make the task of shotgunning a circuit
board easier, usually without adding additional solder.
Shotgunning is re-soldering all the connections on a
suspected intermittent circuit board.
Even desoldering is easier. Cheap solder wick often has
too little flux in it, and the solder sucker method is vastly
improved by a touch of flux before the heat is applied.
Cleaning Up
Tip Cleaning
You will get the best results if you begin with a clean
soldering iron tip; so at the end of every session, clean
it so it will be ready for the next task. Most electronics
stores sell tip-cleaning sponges. The sponge is soaked
in water, rung out, and placed in a convenient metal
holder. Wipe the tip across the sponge with a rotary
motion to remove burnt flux and crystallized solder.
Clean Up Your Act
When the soldering is done, the flux remains. The
yellowish brown residue should not be left on the board.
It makes your work look ugly and unprofessional, and if
any moisture or condensation is present, it can support
the growth of fungus, which will damage the circuit
Most electronics stores sell flux remover, which will make
cleanup simple. Don’t spray the whole board, however.
This can cause condensation, as the alcohol-based
chemical becomes cold when sprayed.
For small areas, soak a wooden swab, and wipe. For
heavy concentrations, chip the flux off first. Be careful
where you spray this stuff; some formulas will eat plastic.
It makes a good paint remover too, and is usually quite
Melting Plastic with Your Soldering Iron Tip
Another thing that will affect the cleanliness of your
iron is plastic. If, by accident, your iron should come in
contact with plastic, clean it off with a damp rag. Tin the
tip well with fresh solder and clean again. Lightly tin it
again, leaving it ready for the next job. Plastic left to burn
on a tip will quickly remove the plating from the tip and
can actually cause craters to form. The tip will bend and
break soon after.
210 Rock Point Drive
Durango, CO 81301
(970) 259-0690 Fax: (970) 259-0691 Email: [email protected]
New Dimensions in Digital Sound Technology
©1996-2011 Throttle Up! Corp. All Rights Reserved
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF