Adafruit Guide To Excellent Soldering
Created by Bill Earl
Last updated on 2014-06-28 08:30:54 PM EDT
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Guide Contents
Guide Contents
Tools
Building a Soldering Toolkit
Choosing a Soldering Iron
Basic Irons
Better Irons
Best Irons
Irons to avoid
For emergencies only:
Not for circuit board use:
Essential Tools and Supplies:
Stand
Solder
Diagonal Cutters
Other Handy Tools and Supplies
Vise
Third Hand
Solder Sucker
Solder Wick
Preparation
Heat the Iron
Clean the Iron
Tin the Tip
Make sure that the joint is clean
Immobilize the Joint
Steady the Board
Making a good solder joint
Heat the joint
Apply the solder
Let It Flow
© Adafruit Industries https://learn.adafruit.com/adafruit-guide-excellent-soldering Page 2 of 35
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Let It Cool
Trim the Lead
Congratulations!
Problems?
Surface Mount Components
Immobilize the Joint
Heat the Joint
Apply the Solder
Let it Flow
Let it Cool
Problems?
Common Soldering Problems
The Ideal Solder Joint
Disturbed Joint
Cold Joint
Overheated Joint
Insufficient Wetting (Pad)
Insufficient Wetting (Pin)
Insufficient Wetting
(Surface Mount)
Solder Starved
Too Much Solder
Untrimmed Leads
Solder Bridge
Lifted Pad
Repairing a Lifted Pad
Stray Solder Spatters
All of the Above!
© Adafruit Industries https://learn.adafruit.com/adafruit-guide-excellent-soldering Page 3 of 35
Tools
Building a Soldering Toolkit
If you are just getting started in Electronics, Ladyada's Electronics
Toolkit (http://adafru.it/136) (pictured above) is a great kit full of quality tools - including
everything you need to make great solder joints. If you would rather build your toolkit pieceby-piece, read on:
Choosing a Soldering Iron
There are many types of soldering irons. For most Adafruit kits and projects, you will want a
pencil-style soldering iron with 25 watts or more.
An under-powered iron is a poor investment. It will end up costing you more in ruined kits
and damaged components.
It will take longer to heat the joint, allowing heat to spread to the component being
soldered - potentially overheating and damaging the component.
Longer heating times will also give more time for oxides to form on the surfaces being
soldered. This will prevent the solder from flowing and result in a poor joint.
Longer recovery times between joints can result in frustration, 'cold joints' or both.
You don't need to spend a fortune to get a good iron. Advanced features such as
temperature control and interchangeable tips are nice to have, but not essential for
hobbiest-level work.
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Basic Irons
There are many basic pencil style irons that are
suitable for hobbiest use. But you will need
one that is capable of heating the joints quickly
enough. Choose an iron with 25 watts at a
minimum.
Better Irons
An adjustable temperature iron with a little
more power will give you a bit more control and
allow you to work faster. The Adjustable 30W
110v Soldering Iron (http://adafru.it/180) in the
store is an excellent choice.
This iron is also available as part of Ladyada's
Electronics Toolkit (http://adafru.it/136), which
contains many other essential soldering tools.
Best Irons
A professional-style temperature-controlled
iron with interchangeable tips and 50 watts or
more of power is a joy to work with. Feedback
control keeps the tip temperature at precisely
the level you set. The extra watts speed
recovery time so that you can work faster.
Interchangeable tips let you select the ideal tip
shape for specialized work.
The 65 watt Hakko FX-
888 (http://adafru.it/303) is an
excellent professional quality soldering iron.
The Weller WES51 or WESD51 are also
excellent choices for serious electronics work.
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Irons to avoid
In addition to underpowered irons, there are several types of irons to avoid for general
circuit-board work.
For emergencies only:
These irons are handy for occasions when you
have no place to plug in a regular soldering iron.
But they are not the best choice for a primary
soldering tool:
Butane Po wered Iro ns have plenty of
power but are difficult to control.
Battery Po wered Irons are generally
underpowered for most work.
Not for circuit board use:
These tools are not suitable for circuit board
work:
Torches of any kind are not suitable for
electronics work and will damage your
circuit boards.
Soldering Guns are OK for working with
heavy gauge wires, but don't have the
precision necessary for soldering
delicate electronics components.
Cold-Heat™ Irons inject current into the
joint to heat the tip. This current can be
damaging to sensitive electonic
components. Avoid these irons for
electronics work.
Essential Tools and Supplies:
These tools are the bare-minimum essentials required for soldering:
© Adafruit Industries https://learn.adafruit.com/adafruit-guide-excellent-soldering Page 6 of 35
Stand
If your soldering iron does not have a built-in
stand, you will need a safe place to rest the hot
iron between uses. A Soldering Iron
Stand (http://adafru.it/150) will keep your iron
from rolling around and protect both you
and your work surface from burns.
Most stand holders come with a sponge and
tray for cleaning your soldering iron.
Solder
Standard 60/40 lead/tin Rosin
Core Solder (http://adafru.it/145) is the easiest
type to work with.
Diagonal Cutters
You will also need a pair of Diagonal
Cutters (http://adafru.it/152) for
trimming component leads after soldering.
Other Handy Tools and Supplies
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These are some other tools and supplies you might find useful when working on soldering
projects.
Vise
A vise holds your work steady as you solder.
This is important for both safety and sound
joints. The Panavise Jr (http://adafru.it/151) is
an ideal size for most Adafruit kits and
projects.
Third Hand
A Helping Third Hand (http://adafru.it/291) Tool
is a good for smaller boards, or to hold things in
place while terminating or splicing wires.
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Solder Sucker
A Solder Sucker (http://adafru.it/148) is a very
helpful tools for removing excess solder
or when you need to de-solder a joint. As the
name implies, this device literally sucks the
solder out of the joint.
Solder Wick
Solder Wick (http://adafru.it/149) is another
way to clean excess solder from a joint. Unlike
the solder sucker, the wick soaks up the
molten solder.
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Preparation
Heat the Iron
Plug an and/or turn on your soldering iron to
warm up. If you are using a temperature
controlled iron, set it to 700F/370C for 60/40 or
750F/400C for lead-free solder.
While the iron is heating dampen the sponge
with a little bit of water.
Clean the Iron
Wipe the tip of the hot iron on the damp
sponge to clean off any oxidation.
Do not use files or abrasives to clean the tip. It
will damage the plating and ruin the tip.
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Tin the Tip
Apply a small amount of solder to the tip and
wipe again to tin the tip. You should have a
thin, shiny layer of molten solder on the tip of
your iron.
If the tip is badly oxidized and difficult to tin, it
can usually be reconditioned with some tiptinning paste.
Make sure that the joint is clean
Dirt, oxidation and oily fingerprints can prevent
the solder from wetting the solder-pad to
create a solid joint. All Adafruit boards are
plated to prevent oxidation, but if your
board appears dirty from storage or handling,
wipe it down with a little isopropyl alcohol.
Immobilize the Joint
This is very important! The parts being joined
must not move during the soldering process. If
there is any movement as the molten solder is
solidifying, you will end up with an unreliable
'cold joint'.
Most through-hole components can be
immobilized by simply bending the leads on the
solder-side of the hole.
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