Soldering 101

There are several types of solder, soldering irons, and iron tips for different applications.  Here we are mainly focusing on guitar and amplifier electronics.  Before learning the technique of soldering it is important to understand what to use for a particular job.

Choosing the Right Soldering Iron (avoid using soldering guns if you can)…..

25-30 Watt Irons
Great for delicate PCB work where less heat is good, though not recommended for hand wired electronics because it can require more time to heat up the bigger solder joints which may damage the component before the solder can melt.
35-40 Watt Irons
Ideal for most guitar and amp electronics, especially the hand wired components.  The higher wattage requires less time to melt the solder joint, so you reduce the risk of overheating the components.
Variable Heat Irons
These are the best because you can adjust the heat to handle almost any job.  You can reduce the heat enough to work on delicate PCB’s, or increase it enough to solder Humbucker covers or any large surface that absorbs heat and makes it difficult to solder.

Choosing the Right Tip…

Chisel Tip (L), Pencil Tip (R)

Chisel Tips – These come in all sizes. They have a flat head which helps to better disperse heat across bigger surfaces.  A small chisel tip is good for most hand wired components that have solderable lugs.  Medium to large sized tips are great where high heat is needed, such as soldering Humbucker covers to a base plate, or soldering directly to a chassis.

Pencil Tips – These are pointed and designed to focus heat directly to one central point.  Pencil tips are ideal for PCB’s or any smaller solder connections.  They can also be great for crammed wiring where a chisel tip won’t reach without burning surrounding wires or components.

Choosing the Right Type of Solder…

This should be pretty self explanatory.  Just use a rosin core solder, like 60/40 or 66/44 which are most common.  The thinner the solder the better it is to work with.  You do not need to use flux with rosin core solder since the rosin is the flux.
Kester ”44” Rosin Core Solder .062 Core 66 Flux 44
Item No. 1000015a***SPECIAL ***

Let the Soldering Begin…

If there has ever been any mysticism or uncertainty about soldering, let us clear it up for you today.  While doing it right means less chance of a bad connection between components, there is nothing about it that should cause apprehension.  Follow these steps, practice practice practice, and commit them to memory.  You’ll be great at soldering in no time.
Step 1: Plug in your soldering iron, and wait for it to reach a good operating temperature.  For most applications, you’ll know you’re good to go when you can melt solder with the tip.
Step 2: Make sure the surfaces of the components are clean and clear of any debris. The only way for soldering to work is if metal is being soldered to metal.  If you are soldering a component to a PCB for example, you may have to scrape a bit of the PCB’s overlay coating from a trace to make a good connection.
Step 3: Secure the components together. More specifically, make sure the components are contacting each other at the point at which the connection should be made, and that they will not move when you apply the iron and solder to them.  This is important because you stand a good chance of creating a cold solder joint if the components move around during soldering.  A cold solder joint occurs when one of the components is heated enough to receive a good solder bond, but the other component is not heated enough due to an aforementioned movement or bad iron placement.  This is a failed solder connection.
A good way to stabilize everything together is through the use of alligator clips or a set of helping hands.

Step 4: Is your soldering iron ready?  Here is the key to a proper soldering technique:
  • Touch the iron to the area to be soldered.  Make sure the iron touches all of the components including the PCB if applicable.  This may take a few approaches at different angles before you get it right.
  • A few seconds later, touch the area with solder.  When it begins to melt, move it around the components for even coverage− no globs.
  • When everything is covered, take the solder away while keeping the iron on the area.
  • A few seconds after that, remove the iron while making sure nothing moves in the process.
  • After the solder hardens, give all the components a tug to test the bond.  Nothing should seem loose.
Your process should not deviate from this order.  Apply heat, apply solder, remove solder, and remove heat.  Practice this, and you will become a soldering master.
Now, what’s a good way to insure you’ve soldered properly?  Test it with an Ohm meter. Take a reading with the black probe on one side of the connection, and the red probe on the other side.  A good connection will read 0 to 10 Ohms max.  A connection needing attention will read O.L. (an open circuit) or some high resistance.
Need something to solder?  Try one of our Amp Kits or a Guitar Kit.
Pre-tin your leads with solder before making the connection.  This is most important with stranded wire because the strands need to be completely penetrated with solder in order to make a solid connection.  In summary, tin the wire, tin the part, heat both parts and join them to you will insure a better connection every time.

Click Image to Enlarge
Be careful not to overheat components, especially solderable lugs.  Remember that lugs are an extension of a contact point of a switch, jack, tube socket, or potentiometer. Overheating can make the solder to run down into the contact point causing it to fail or seize. When you see the solder start to “flow” onto the connection, then immediately remove the iron. This will prevent solder from “overflowing” into the contact point.
Always wear eye protection and solder with adequate ventilation. You never want to have solder smoke billowing around your face. Solder smoke is toxic and absolutely bad to breath. Use a fan or something to pull the solder smoke away from you. Also hot solder can fling or spit rosin which may damage surrounding finishes, or injure you, so always wear eye protection and protect the surfaces around your area.

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  • Ebbesen Davis

    A lot of this information you’ve provided is very helpful, but your recommendation for a solder type, “Just use a rosin core solder, like 60/40 or 66/44″ is not the best advice you could offer. Both of these solders contain lead, and the electronics world is quickly moving towards more environmentally responsible, lead-free solder and components. Many new lead-free solder formulas have become available, but making this transition is not always an easy experience. That’s because the new soldering materials act differently from traditional solders, and many require higher wattage equipment – and, while some lead-free solders work extremely well when handled properly, others don’t appear to work well at all.

    Since you are continually providing up-to-date information to your customers, perhaps you could experiment with currently available lead-free solders and report your findings to us. I suppose there are some old die-hards who wouldn’t care, but you might be surprised at how many of us would. Thank you for providing us this means for comments, and thanks for all of the good information you provide!

    Best Regards,

    Ebbesen Davis

    • Robert Hull

      Lead Free solders require a specialized technique (and tools) to implement. These “lead free” techniques for the casual solderer can be a challenge. If one is changing to lead free for personal environmental concerns, that is fine for them. However, the performance of lead free solders are no better (and my experiences have been worse) than leaded solders. As an “old die-hard” (and many of us out there who solder on a daily basis are), I recommend leaded solders for the Soldering 101 crowd. If one’s conscience and funds afford (or if one is selling product to the EU), then transition to the lead-free types would be expected. Until then, 60/40 or 63/37 types RA rosin core types are preferred.

      Robert “old die hard” Hull

  • Lee Tingler

    My name is lee Tingler the Author of the Artful Solderer One of your customers pointed out your mistake. 66/44 it should be 67/37 You people may be interested in reading my book on soldering practices. I also teach the subject on the college level. my website is Enjoy!

  • Groundlug

    You guys are funny. I learned how to solder like a pro in like 5 minutes. Good info though Mojo. Thanks.

  • HighOrder

    I appreciate what Mojo does in providing videos and information to help folks out. Good service and good folks. I’ve been soldering on the job and as a pickup builder for over 30 years, having been through a shortened version of the Nasa High Reliability Soldering school as a young Airman. The truth is, rosin core solders really are not adequate alone in providing enough flux/cleaning action for a superior solder joint. The tinning job shown in the pictures is indicative of that. Dabbing a little flux on the wire prior to applying the solder will make a world of difference in the results. You should see the individual strands of wire “in relief”, as it were, with a high shine and no pits. What you have there will work for the most part, but you could “kick it up a notch”. Flux is easy enough to clean up with 91% Isopropyl. Thanks for the tips and the quality of service you provide. Just food for thought.

  • Lee Tingler

    this is a good practice to clean your site if possible IE 63/37 has a melting point is 361 degrees F 60/40 is 461F so you will see a difference there but it will work. But if you use RoHS Lead free solder you have two things happening here first it is not lead based. Second it melts at 421F and is not compatible with lead based solder so look see a tag or sticker on the product that says RoHS compatible.

    Lee Tingler
    Check out my different products. I have a new one called the ))SPK(( not yet listed great for muscians.