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This instructable is a lesson in my free Electronics Class. To enroll, click here.

The first thing we will cover before we get into the meat and potatoes of electronic components is an intro to soldering.

While you can learn electronics without ever picking up a soldering iron -- in fact, many electrical engineers do -- this is a hands-on electronic class. We are going to be soldering in every lesson along the way. Thus, I am going to get this fundamental skill out of the way from the onset.

This is by no means the definitive guide on soldering, but a brief overview to get you going. By the end of this lesson you should be able to solder with reasonable proficiency.

Step 1: Setting Up Your Workspace

To start, you will want a soldering iron. As a beginner, you can get a 40W fixed temperature soldering iron. These are cheap and will get the job done for what you are doing while you are just getting started. By the time you decide you want to continue deeper into electronics, it will likely be time to upgrade to something more refined.

If you already have some experience soldering, or want to start with the luxury model, you can get an adjustable temperature soldering iron. Having an adjustable temperature is nice because it allows you to work with different types of solder and components with more precision. These soldering irons also typically heat up faster. They also tend to have a much wider array of replaceable tips to work with for all kinds of specialty purposes. As you begin to understand how soldering works, you will eventually want upgrade to one of these.

The two most popular methods for cleaning the tip of the soldering iron involves using a brass wire pad or a slightly damp sponge. Both work. However, deciding which works better is a highly contentious topic. Personally, I feel the the brass wire pad is more effective in quickly cleaning the tip. From what I can tell, advocates of the damp sponge feel it keeps the tip cleaner for longer.

There are two types of wire you should always have on hand when working with electronics. It is highly advised to have both solid and stranded 22AWG wire in red, black and green (or - really - any color not red or black).

Like wire, solder comes in spools and of different thicknesses. The solder I like working with is in the 0.02 - 0.04" range. It is important not to get solder that is too thin because you will have to heat up your parts for too long in order to melt enough solder onto it. It is also important to not get solder that is too thick or you will get too much solder all over the board, which aside from being messy can result in mistakes.

The other choice you need to make is to use solder with (pictured left) or without lead (pictured right). It is recommended that you use lead free solder. However, keep in mind, that just because it is lead free does not mean it is any better for you. Lead free solder has replaced the lead with other additives and actually produces more caustic fumes when melted. Lead free solder also melts at a higher temperature and is harder to work with. On account of this, you might at some point be tempted to work with lead solder. If you do, remember to always wash your hands after handling it!

Desoldering braid is a copper mesh used to remove solder from a circuit board. When the solder gets heated up, the mesh wicks the solder away and helps remove excess. This is particularly helpful for trying to repair soldering mistakes. While this is helpful, it should always be thought of as a line of last defense.

Helping hands is basically a stand with two (or more) alligator clips attached. As the name implies, it is extremely helpful. These are sometimes called a "third hand," and as you can guess by that, this is basically used in those instances when a third (or fourth) hand would be handy. This is particularly useful for holding components in place while soldering. Many come with a magnifying glass, which is great for inspecting solder pads and reading the tiny print on components.

Depending on your ambient lighting, and overall optical dexterity, you may want to consider getting a desk light. Electronic components and solder connections are small. To see things well, it sometimes helps to have more light.

Last, but not least, you will want a fan or some other form of ventilation. I highly recommend one like the one pictured, with an activated charcoal filter. This will not only suck the air away from you, but filter out some of the particulates from continuing to circulate in the room.

Step 2: Holding the Soldering Iron

A soldering iron is held like a pencil, but with one significant difference. Instead of holding it by the tip, you hold the soldering iron further back by the insulated handle.

That's all there is to that.

Step 3: Safety Concerns

Never touch the metal part of the soldering iron while it is turned on. This can result in nasty burns, and is generally unpleasant.

Never leave soldering iron resting on the table. It will burn your work surface and could potentially start a fire.

Soldering can build up a mighty appetite, but don't eat while soldering. Some solder has lead in it, a known carcinogen. Even lead free solder has things in it you likely do not want to ingest. Before chowing down on a slice of pizza, turn off the soldering iron, take a break, and wash your hands with soap and water.

Breathing in the fumes from soldering is bad for you. Always use some sort of ventilation fan to minimize your exposure. Your lungs will thank you.

While arguably not necessary, it is recommended that you wear safety glasses while soldering. Solder has been known to splash and splatter. Albeit a rare occurrence, getting burning hot solder in your eye can be an unpleasant experience (or bits of cut wire, for that matter).

After soldering, you will always want to remember to wash your hands with soap and water.

Step 4: Tinning the Iron

Turn on the soldering iron and wait for it to heat up. If you splurged on an adjustable temperature model, you can dial yours in to about 650 degrees.

Once it is heated up, you will want to tin the tip before using it for the first time.

All this involves is thoroughly melting solder all over the tip of the iron. This makes sure the tip has a nice solder coating, which will make it easier to melt solder the next time you use it.

Step 5: Cleaning the Iron

Every time you melt solder using the tip, you will want to clean it off.

To do this, simply drag the tip 2 or 3 times across the cleaning pad.

Step 6: Soldering Wires

Let's start by soldering wires together.

To do this, strip the insulation off of the ends of two pieces of stranded wire using your wire stripper.

Slide a 1" piece of shrink tube onto one of the wires and then twist the two ends of wire together.

Place the soldering iron against the wire to heat it up, and push the solder into the wire. It should start to melt and get wicked up into the wire, coating it in silver.

Remove the soldering iron to let it cool.

Trim the excess parts of wire so the connection is as compact as possible.

Slide the heat shrink tube over the solder joint.

Shrink it into place with a heat gun.

Congratulations! You have just soldered something together.

Continue practicing this until you feel comfortable.

Step 7: Through-Hole Soldering

Aside from soldering components together free-form like we did with the wire, the other type of soldering you will do in this class is to attach components to a circuit board.

There are two types of printed circuit board or PCBs you will encounter when prototyping. There are boards with bus pads, where multiple holes are connected together electrically with a single piece of copper. There are also boards with individual pads. These require you to make connections between components by bridging the different pads with wire, or sometimes just solder.

Regardless of which board you select, the technique we are going to use for attaching components to a circuit board is called through-hole soldering. It is called this because the components we are using have wire leads which pass through holes in the PCB before being soldered.

To demonstrate this, let's solder a resistor to a PCB.

To begin, bend the resistor leads to a 90 degree angle and pass them through the PCB from the top silk-screened side to the side with the metallic pads.

Next, flip the board over, and with the metal pads facing upwards.

Place the soldering iron at the joint between the component lead and the board to heat it up. Push the solder into this joint until it melts and joins the resistor's lead to the solder pad.

It should look like a shiny, and like a a small pyramid between the solder pad and the component lead.

The last step is always to trim away the excess component leads to make the solder connection as flush to the board as possible without breaking it. Be mindful that the wire lead may go flying some distance when you snip it.

Congratulations! You have just soldered something to a circuit board.

Step 8: Common Mistakes and How to Fix Them

When you are just getting started soldering circuit boards, you are going to make some mistakes.

One of the most common is a cold solder joint. This is caused when the soldering iron is not hot enough, and the solder isn't able to melt fully. This typically looks like a rounded dull bulbous blob of solder. The trick to fixing this is simply to reheat the solder and wait for it to cool again without disturbing it as it settles.

Overheating and peeling up the solder pad can be a tricky problem. To fix this, remove any parts of the pad that might be sticking out or bridging another connection. Then, you can use the component's wire lead, or a small piece of wire to make the solder connection between the components you are trying to join.

Another common mistake is bridging solder pads or connecting the pads together. This can be solved by removing solder.

While many mistakes can be fixed by reheating the solder, or adding a little bit more, more often than not, you will need to remove some solder. There are a number of techniques for doing this, but I have found the most reliable is desoldering braid. While it might seem complicated, desoldering braid is basically a mesh of very thin copper wire that wicks up melted solder.

To use it, simply place the braid atop the solder you are trying to remove, and press down upon the braid with the soldering iron.

You will feel the solder begin to flow and see the braid begin to turn silver. After a moment, lift the soldering iron and remove the braid from the circuit board before it can re-solidify (and get stuck to the board).

A significant amount of solder should be removed, and the mistake should now be corrected. If the mistake persists and more solder still needs to removed, wait for the board to cool off, and repeat the process.

<p>I've worked in the electronics industry for the last 27 years. Solder fumes are not good for you and can cause occupational asthma and other health problems, but generally that takes years of breathing fumes on a regular basis. I know plenty of technicians that never used a fume extractor fan and breathed fumes every day for years without any health issues. You are not breathing in lead, just the fumes from the melting rosin. Lead melts, it does not vaporize at soldering temperatures. I highly recommend a well ventilated area, but hobbyist should not be unduly concerned with the vapors unless they have a history of respiratory problems. The bigger issue is ingesting lead. If you do any soldering at all there will be lead left on your hands and bench. If you eat without washing your hands you will ingest lead which is the main cause of lead poisoning. Always wash your hands and wipe down you bench after soldering.</p><p>On solder braid, I never buy &quot;No Clean&quot; solder braid. No clean braid lacks rosin which really helps the braid to effectively soak up the solder. It is a little messier as it leaves rosin residue behind, but that is easily removed with a little isopropyl alcohol and a cotton swab. The frustration of having to clean you board is nothing compares to the frustration of trying to absorb solder with &quot;no Clean&quot; solder braid.</p>
<p>I always leave the component leads long because you are less likely to overheat small components.</p><p>Also, I insert about 10-20 passive components at a time and I bend the leads outwards slightly so that they don't fall out. This also allows me to check for mistakes more easily before I solder them all into place. It also means that you have a nice 'wet' soldering iron so you get much better joints and it is much faster when you do 40 joints at a time.</p>
<p>The picture above that shows the solder being applied to the IRON is incorrect. You use the iron to heat the component lead and the solder pad. The solder is applied to the lead and pad at the same time, on the opposite side of the iron. The solder should flow smoothly onto both.</p>
<p>I should have mentioned that the &quot;picture above&quot; means the picture of the resistor lead being soldered to the PC board. You apply solder directly to the iron tip for tinning the tip but only for tinning. You always apply the solder to the join, not the iron, when soldering.</p>
<p>Overall, this is an excellent 'ible! I completely agree with R.E.K. Another problem I see is students attack the joint with solder and iron, then remove both - and then attack again. This allows the joint to cool down between applications and can result in a non-connection (cold joint). The best method is to place the iron on the pin and pad and leave it there. Keep adding solder (in multiple steps, if necessary) until the joint looks good. Once happy, remove the soldering iron. The iron is the first thing to touch the joint, and the last thing to be removed.</p>
<p>Hi. Nice Instr. Some notes, (not critic&rsquo;s), me 65+ to years, had to go <br>through the &rdquo;real&rdquo; soldering school. That is, to be employed at &rdquo;LM <br>Ericson&rdquo; (the telephone company), you had to take a class for two weeks <br>(14days/ 8 hour), in soldering techniques, and after that to pass a test<br> of making 1.000 soldering joint&rsquo;s and with only 2, (read: two = <br>2/1000), &rdquo;bad&rdquo; ones accepted, I passed. So I guess I know something <br>about soldering? <br>#1 Cut the legs of the component to be in a lenght <br>of to be as desired BEFORE soldering, reason? when heating up the leg to<br> be soldered the &rdquo;heat climbe&rsquo;s up&rdquo; the leg rather than to the surface <br>it&rsquo;s meant to be in.<br>#2 Allways heat up the area where the component is to be and simultionasly heat up the leg<br>#3<br> The soldering lead-core has &rdquo;built-in&rdquo; core of &rdquo;flush&rdquo; resin, that&rsquo;s <br>got much lower melting point that the lead has, why lower? Because the <br>main idea is that when you apply soldering lead to a joint the resin <br>does the &rdquo;clean-up&rdquo; job for you before the lead comes there.<br>#4 <br>Newer, Ewer use the use the tactic&rsquo;s of to apply lead directly to the <br>tip of the soldering iron, (with one exception: when re-cleaning the <br>tip, then it&rsquo;s HIGHLY recommended, because then the resin does &rdquo;just&rdquo; <br>that it&rsquo;s meant for), because if you do the only thing you acchive is to<br> bourn out the resin that was meant to clean up the target area<br>#5 <br>For me it&rsquo;s kind of a reflex, (like breathing), to clean the tip of my <br>soldering iron ewerytime I release it, (put it away between ewery <br>solder), (me made about 1,000,000+ solderings), thus having them SAME <br>soldering tips and the wery same soldering station, &rdquo;Weller&rdquo; not an ad. <br>here but anyway. Get quality, it pays off.<br>Repetition: &rdquo;Allways Heat <br>up the subject and the surface to be attached to&rdquo;, if that want work <br>firmly, then you have a &rdquo;dirty&rdquo; surface or a &rdquo;dirty&rdquo; component leg, <br>(have had this dirty component leg 100&rsquo;s of times).</p>
<p>Hi. Nice Instr. Some notes, (not critic&rsquo;s), me 65+ to years, had to go through the &rdquo;real&rdquo; soldering school. That is, to be employed at &rdquo;LM Ericson&rdquo; (the telephone company), you had to take a class for two weeks (14days/ 8 hour), in soldering techniques, and after that to pass a test of making 1.000 soldering joint&rsquo;s and with only 2, (read: two = 2/1000), &rdquo;bad&rdquo; ones accepted, I passed. So I guess I know something about soldering? <br>#1 Cut the legs of the component to be in a lenght of to be as desired BEFORE soldering, reason? when heating up the leg to be soldered the &rdquo;heat climbe&rsquo;s up&rdquo; the leg rather than to the surface it&rsquo;s meant to be in.<br>#2 Allways heat up the area where the component is to be and simultionasly heat up the leg<br>#3 The soldering lead-core has &rdquo;built-in&rdquo; core of &rdquo;flush&rdquo; resin, that&rsquo;s got much lower melting point that the lead has, why lower? Because the main idea is that when you apply soldering lead to a joint the resin does the &rdquo;clean-up&rdquo; job for you before the lead comes there.<br>#4 Newer, Ewer use the use the tactic&rsquo;s of to apply lead directly to the tip of the soldering iron, (with one exception: when re-cleaning the tip, then it&rsquo;s HIGHLY recommended, because then the resin does &rdquo;just&rdquo; that it&rsquo;s meant for), because if you do the only thing you acchive is to bourn out the resin that was meant to clean up the target area<br>#5 For me it&rsquo;s kind of a reflex, (like breathing), to clean the tip of my soldering iron ewerytime I release it, (put it away between ewery solder), (me made about 1,000,000+ solderings), thus having them SAME soldering tips and the wery same soldering station, &rdquo;Weller&rdquo; not an ad. here but anyway. Get quality, it pays off.<br>Repetition: &rdquo;Allways Heat up the subject and the surface to be attached to&rdquo;, if that want work firmly, then you have a &rdquo;dirty&rdquo; surface or a &rdquo;dirty&rdquo; component leg, (have had this dirty component leg 100&rsquo;s of times).</p>
<p>Some &quot;grammatical&quot; errors here, like &quot;bourn&quot; should be = &quot;burned&quot; ? Me a FIN, so be nice with my &quot;gramma&quot;</p>
<p>I would like to add a couple comments to this excellent instructables. The lead free solder will not have a shiny surface like leaded solder has. When clipping wire leads take another look at the soldered lead. Some times clipping the lead will fracture the solder and cause problems down the road.</p>
<p>So right You are. Actually it&rsquo;s an alloy of Sn/Pb, usually in propotion of 60/40.<br>The leadless solder requires a higher melting temperature point to fullfill the task requiered. Thus making us to &rdquo;re-establish&rdquo; them &rdquo;standard&rsquo;s&rdquo; of them &rdquo;acceptably requirement&rsquo;s of a good soldering&rdquo;. Untill these days you could decide wheter the solder is &rdquo;good&rdquo; or not, just by looking at it, &rdquo;shining&rdquo;, (Jack Nicholson), or not? If not, then questionable, may or may not to be good?</p>
<p>Gee&hellip;.. Just love Ya. You made my day. Got a good laugh with them animations with them component&rsquo;s. I hope You don&rsquo;t mind my them comment&rsquo;s in Your soldering class? <br>It is all fine, both tech. and vis.</p>
<p>Can you give a tip on how to solder to a COB type LED. There is a tinned section for both leads but I am unable to get solder to stick. I end up with a burnt paste mess that I have to remove but it still doesn't work. I can add an image if I'm not making sense. LMK.</p>
Merci, c'est complet et amusant :)
<p>Very good tips. To make good solder connections also takes practice. Very few of us made good solder connections the first few times.</p>
<p>A note on picking an iron. There are 2 ways that solder irons and pencils are heated. Some use a wire wound heater and others use a ceramic heater that fits inside the tip. Both will heat the tip to melt solder but the ceramic heater doesn't hold the heat long enough for soldering large joins or heavy wire. If you are working on old vacuum tube equipment or soldering to a metal chassis you will also need a good soldering gun of at least 100 to 200 watts.</p>
<p>thank you so much sir.</p>
<p>Excellent tutorial</p>
<p>Thank you ☺ </p>
<p>Great! Thank you!!</p>
<p>Overall this is a fairly comprehensive lesson. There are a few things I'd like to mention, though:</p><p>- When in doubt, apply flux. This solves over 95% of all cold/ poorly connected/ ugly solder joint issues. Make sure to get electronics rated flux (I prefer the pen version).</p><p>- Do not get a crappy soldering iron. They only lead to crappy solder joints and a lot of frustration. You can get decent regulated ones for as low as 20&euro; (sourced from china). I've been using a brand name 30W soldering iron for years before switching to a non-brand regulated soldering station and I'd never, ever go back.</p><p>- Tin the iron not only before use, but also when you leave the workspace. The tin prevents the tip from forming an oxide layer which is hard to get rid of. Never use a file or sandpaper, it will damage the outer metal layers of the tip.</p><p>- There are instructables to solder cables in a better, more reliable way.</p><p>- A desoldering pump costs only a few dollars and can save you tens of dollars worth desoldering braid. This is especially useful for reclaiming used components.</p><p>- Get FR4 based prototyping boards. They cost a little more, but the pads tend so stick better to the board.</p>
nice and informative, I've been looking for a good beginners guide to soldering and this one's fantastic. thanks for making it !

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Bio: My name is Randy and I founded the Instructables Design Studio. I'm also the author of the books 'Simple Bots,' and '62 Projects to ... More »
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