Soldering Through-Hole Components Into a Circuit Board
By: Evan Wall
Advanced Organizer
This document is directed at Pennsylvania State University electrical engineering students in the course
EE210. This document will help prepare EE210 students for the final project in which they must solder
many components into a through-hole circuit board. This document will discuss proper procedure for
soldering these components. This document is broken up into 4 parts; the advanced organizer,
Background information, Items required, safety tips, instructions, conclusion, and works cited. The
advanced organizer is first so that the context and the organization may be established for this
document first, then the required items are provided so that they may give context for the safety
precautions, then any necessary safety precautions are taken before the dangerous activities begin in
the instructions. The instructions given with a larger font so that they can be read more easily. The
conclusion elaborates on the purpose of this document, and where to gain more knowledge of this
subject. The works cited is the final item as it is not necessary to achieving the purpose of this
document.
Background Information
Soldering is an ancient and sacred art that has been around for thousands of years. Soldering is a form
of metal working which has been dated back roughly five thousand years. The ancient Egyptians and
Trojans were the first known groups to conjoin two metals together using a technique similar to
soldering. It was not until roughly four thousand years ago that soldering was truly born through the
discovery of tin. Tin allowed for two metals to be conjoined by soldering because tin had such a low
melting point that the tin would become liquid before any other metal would even be damaged by
heat. The ancient Romans were known to have some of the most incredible feats of soldering. They
soldered together 400km long lead pipes, furnaces, armor, and works of magnificent golden art.
Recent developments over the past hundred years has led to advances in soldering technology and the
mass production of soldering equipment which is now widely used in the electronics industry.[1]
Terminology
Leaded: A component which was leads or wires extruding from it.
Through-hole: A hole in a circuit board to which a component may be attached. A typical through-hole
has a metal pad around the hole to encourage conductivity and create a location for the solder to bond
to.
Clips or “Third-hands”: A device with clips and a heavy metal base which is used to suspend items in a
specified orientation and position.
Required Items
Items not shown
• Leaded item to be soldered
• Well ventilated location
• Work bench
• Metal file (optional)
Safety Goggles
Soldering iron (low
wattage; 15-40 Watts)
Wire strippers (only necessary
if soldering wire.)
Circuit board with
through-hole sites
Wire cutters
Set of clips or set of “third
hands” (anything which will
hold components in place)
Solder (lead-free)
Damp sponge or
damp paper towel
Safety Tips
Warning: Always wear safety goggles when soldering . Getting hot solder on your cornea
will instantly result in blindness in one eye. Do not contact the heated part of the
soldering iron to anything other than: solder, the stand, or the items which are being
connected. Do not perform any tasks other than soldering when holding the soldering
iron. Use a low power soldering iron to help prevent serious burns. If burnt immediately
place soldering iron in stand and unplug soldering iron then consult a person trained in
first aid or a medical professional.
Instructions
Preparation
1. Clear an area on the workbench of all items which are
not in the required items list.
2. If the soldering iron is dull or has any materials covering
the tip, file of any extra material and file until the soldering
iron has a pointed tip once again.
Caution: Read the instructions
thoroughly before beginning
any soldering. You should not
be soldering and trying to read
the instructions, or doing any
kind of multitasking while
soldering.
3. Place soldering iron on soldering iron stand.
4. Plug in soldering iron. If the soldering iron has a
temperature setting, set to high or medium-high heat.
5. Wait for soldering iron to heat up. This may take
anywhere from 2 to 10 minutes. You can check the heat by
lightly touching the soldering iron to a damp sponge. If the
water sizzles, then the soldering iron is hot enough. You
may also check the temperature by trying to melt a small
Step 5:
Checking the
temperature
of the
soldering
iron
amount of solder with the soldering iron.
6. If you are soldering a wire to the circuit board, make sure
the wire is stripped of its rubber coating to allow for at
least a half inch of exposed wire.
Step 6: Wire coated with rubber
and ½” of exposed lead.
7. Take the component that is going to be connected to
the circuit board and place it into the hole in the circuit
board, make sure that the component is in a position
similar to its final position.
Soldering
8. Once the soldering iron is hot, connect the soldering
iron to the wire or lead of the component which will be
connected to the circuit board.
9. Connect the solder to the lead, do not connect the
solder to the soldering iron, this will cause a poor
connection and a weak solder joint. Sustain the
Steps 8 and 9 [2]
connection of solder and lead until the solder begins to
melt onto the lead.
10. Guide the melted solder to the copper pad of the
circuit board. Use only enough solder to form a small
cone at the connection between the copper pad and the
Step 11: Wiping away extra
solder on a damp sponge
lead.
11. Wipe any extra solder from the soldering iron onto a
damp sponge or damp paper towel.
Step 13: Snipping extended lead
12. Place the soldering iron on the soldering iron stand.
13. Use the wire cutters to remove the part of the lead
extending beyond the board on the opposite side of the
component.
14. Repeat steps 7 through 11 for each lead and
component which will be added to the circuit
board.
Clean up
15. Unplug soldering iron.
16. Let the soldering iron cool for about 20
minutes, and wait until the soldering iron is at
room temperature.
Flowchart of steps
Conclusion
Once the soldering iron is cool you are all done. Congratulations! Hopefully you didn’t sustain any
serious injuries or damage.
Now that you know the steps necessary for proper soldering and you know the required safety
precautions, you are one step closer to becoming a full-fledged electrical engineer. When first
learning soldering it is highly unlikely that the finished project will look nice, and you will likely have
to resolder multiple components. As you gain experience with soldering your results will drastically
improve and you will be able to solder faster, more effectively, and the final product will look much
nicer as well. If you would like to learn more you may visit this website
<http://www.instructables.com/id/How-to-solder>. This website is a tutorial which goes into much
more detail regarding soldering. It covers more advanced topics like using soldering guns and
soldering cables together. This website teaches you soldering in a much more diverse array of
projects. Good luck on your future soldering endeavors and may the black smoke of your circuits
forever flow in your favor.
Citations
[1]"Soldering History." Kurtz Ersa. ERSA, n.d. Web. 10 Apr. 2014. <http://www.ersa.com/solderinghistory-en.html>.
[2]"Electronics Primer: How to Solder Electronic Components." Electronics Primer: How to Solder
Electronic Components. Science Buddies, n.d. Web. 10 Apr. 2014.
<http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_primersolder.shtml#soldering>.