How to Solder

This guide focuses on soldering for the beginner and explains how you can solder a variety of components using a few different techniques - from the classy to the downright caveman. Although soldering can seem daunting at first, once you give it a try you will see that in most applications it's quite simple to do.

Please note: this instructable is written for beginners, and contains lots of very basic information. If you have lots of experience soldering, please use the comments to share your knowledge. Clarifications and corrections are especially welcome.

This Instructable was the lead-off for "How to Solder" month, where we rewarded soldering tutorials with Instructables patches. See the original call for project here at submitting a How to Solder Instructable or just check out all the other soldering Instructables here at the How to Solder group.
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Step 1: Tools and materials

Picture of Tools and materials

Soldering is the process of using a filler material (solder) to join pieces of metal together. Soldering occurs at relatively low temperatures (around 400 degrees Fahrenheit) as compared to brazing and welding, which actually melt and fuse the materials themselves at higher temperatures. In soldering the filler material becomes liquid, coats the pieces it is brought into contact with, and is then allowed to cool. As the solder cools it hardens, and the two materials are joined. Soldering is a quick way to join many types of materials, from copper pipe to stained glass. It creates an electrically conductive strong bond between components that can be re-heated (desoldered) if you should ever want to disconnect two items joined together. It's great for joining electrical components and wires and is used in just about everything electronic. In this Instructable I explain how to solder the basics you see in most Instructables: electrical components and wires.

For further information and some more technical specs on soldering check out the wikipedia article.

As with many skills, having the right tools for the job effects the quality of the work being done. When it comes to soldering you can end up using a lot of fancy tools, or just a few simple items you can pick up at the hardware store for a couple of bucks. I am going to use a couple of different soldering tools in this Instructable; there are many ways to solder, and you should use what works for you.

At the very minimum you will need the solder and a heat source to melt it - preferably something small which can get to 600-800 degrees Fahrenheit. If you've got that, your ready to make a connection. That being said, there are a wide range of soldering tools and accessories that can be really helpful if you're going to be soldering frequently. Ladyada has compiled a nice list of equipment and sources to buy the tools on her site. I got together a solid supply of soldering tools by raiding the Squid Labs soldering station. Here is the complete list of what I used...

1. Soldering iron
Most people opt for using a soldering iron to solder. It's a great heat source that heats up and cools down quickly and can maintain a pretty constant temperature. Soldering irons can be purchased from a variety of places. I have picked up some at Radioshack - evil yes, but convenient, some from the hardware store, some from garage sales and a bunch more from retailers online. Low wattage (15-40 watt) soldering irons work best for soldering components on circuit boards while more powerful (60-140 watt) soldering irons work well joining thicker materials like braided speaker wire. If you use too powerful of a soldering iron on a circuit board you might damage the components you are trying to join. I like to keep a low-wattage iron around for detail work, and a high-wattage iron that I can use when I am not too concerned about exposing the material I am working with to high temperatures. It's a real pain to solder thick wires without a powerful soldering iron.

The soldering iron in most of the pictures is made by Weller, and has a variable temperature control. This is the best of both worlds since you can set the heat exactly where you want it, but it's significantly more expensive than fixed-temperature irons. If you're just going to do some occasional soldering it isn't a must have by any means. Anyone interested in modding a soldering iron should check out DIY Hot Air Soldering Iron by charper.

2. Solder
There are lots of kinds of solder available. They come in different thicknesses from around .02" to some really thick stuff you would only use on copper pipe with a butane torch. You use thin solder for detailed work like putting resistors onto circuit boards and thicker solder for joining larger materials like speaker wire. I use solder around .025" for most jobs. Most solder is made from a combination of tin and lead - it's about a 60% tin, 40% lead mix depending on what solder your using. Recent international health codes from Japan and the EU (California and New York have adopted similar policies as well) mandate that lead solder be phased out of certain commercial products and substituted with a lead-free alternative. The manufacturing deadline was this past July so we should be seeing the changes now. Even if you don't live in California or New York its still worth staying away from lead solder since lead has been known to cause all kinds of a nasty health effects from birth defects to severe developmental and neurological damage. Plus it's pretty easy to find the lead-free stuff.

Some solder will contain a small amount of silver. This pushes the melting temperature up a bit, but the silver helps the solder to flow and makes a stronger joint. If you are worried about burning whatever your working with, try to stay away from solder with silver in it, but it works very well if you're just joining wires or something that won't be easily damaged. The last thing to know about solder is that you want to use a solder that has a rosin core. The rosin acts as a flux when soldering and helps the connection - it's also the kind that's most readily available at the hardware store and from electronics suppliers.

3. Soldering iron tips
Soldering irons come with a tip, so you don't have to go out and get a special one, but it's important to know the differences between them and make sure you're using the right tip for the kind of soldering you're doing. Some small-wattage irons come with conical pointed tips for detail work, while most high-wattage irons come with a flatter screwdriver-style tip that works well on wires. You want your tip to be a little smaller than whatever you are soldering so you have good control of what you heat up and what you leave alone.

4. Soldering iron holder and cleaning sponge
It's nice to have a safe place to put the soldering iron down in between soldering. A soldering stand safely holds the iron and gives you a place to clean the tip. Some soldering irons come with their own holders. If yours doesn't have one, you can buy one or make one. jaime9999 has a Homemade nearly-free Soldering Iron Stand that is pretty much identical to what you can buy. The stand isn't a necessity for learning how to solder, but it does help.

5. Tools to work with wires
I have a go-to stock of tools that I round up when working with wires or electrical components. They consist of wire cutters, a wire stripper, needle nose pliers, and an automatic wire stripper (courtesy of the Squid Labs soldering station.) The automatic wire stripper is really convenient if you're going to be stripping lots and lots of wire, but by no means necessary. I have stripped lots and lots of speaker wire using my teeth (not the best idea, I know I know.)

6. Clips to hold your work
Often called "third hands" or "helping hands," these little guys help a whole lot when soldering. You have to hold the soldering iron with one hand and the solder wire in the other, so it really helps to have something else to hold the components you're actually trying to join. You can use alligator clips, clamps, or even some tape to hold things in place if you need to. The third hand is generally a good investment if your going to be soldering regularly, and there are plenty of Instructables with with ideas to modify them if you do happen to pick one up. Check out: Make a 3 degree of freedom 'hand' to help with soldering / gluing work and make your 'helping hands' 100x more useful for soldering / gluing small parts by leevonk to start.

If you would like to make a set of helping hands of your own there are already a number of good Instructables on that too. Quick helper for surface-mount soldering by, QuickMods - Soldering Arms by Aeshir and Build a Pair of Helping Hands by john otto should get things started.

7. Exhaust fan
I do most of my soldering at a soldering station that is equipped with an exhaust fan. It's really not such a good idea to breathe in solder fumes, and soldering does produce fumes. Any kind of ventilation/fan you can rig up will help. Vent the fumes outside or use an indoor fan with a filter if you can't vent them outdoors. Here is a Window-mounted solder fume extractor (not just for RVs!) posted by bikeNomad. Also check out Dr. Solomon's low tech, but functional Solder Fume Extractor if you're looking to build something that you can place right on your table. If you're just doing a quick soldering job, the fumes wont kill you by any means. I have certainly done my fair share of soldering without a vent, but anyone doing repetitive soldering should definitely pick one up or make one.

8. Safety goggles
I hadn't ever used goggles before while soldering, but while doing research for this post I saw it mentioned elsewhere and agree that its a good idea. Little molten bits of solder tend to fly out of the soldering joint when you're feeding in the solder, and if it landed in your eye it wouldn't feel too good.

9. The materials that you want to join together
I was just messing around, and mostly soldering for the purpose of this Instructable so my materials didn't necessarily make anything. You can solder wire, electrical components like resistors and capacitors, circuits, breadboards, electrodes, small pieces of metal and whatever else you can think of. Don't know if it can be soldered? Give it a try - you won't blow anything up.

Once I have got my tools and materials rounded up, I like to pretend that I am a pilot and begin my pre-flight/solder checklist.

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woodswalker5 years ago
I bought a 30W soldering iron from Radio Shack. I'm having a lot of trouble because it takes as long as 90-120 seconds for the solder to heat up. And if I don't touch the solder directly to the iron, it never gets hot enough at all. Plus, the solder doesn't flow well and it turns into balls & blobs. I'm puzzled. What's wrong?
I know this is an old post, but someone may benefit.
There's a few possible problems, the obvious one is you're iron isn't hot enough. I prefer a 40W iron over a 30W any day. It seems 30W are the most common, but they just don't cut it for me.
Try a cheapo model form ebay etc for $5 or so and see how it works for you.
Another fix is to heat the iron up a bit with a torch. I rarely need to do this to boost heat, but I will use a torch as the heat source for the iron if I'm too far from an outlet..

The other problem could be thinking the flux inside the solder is enough. It is not.... At least it has never been for me. You need to flux the surfaces and be sure the surface can be soldered in the first place.
The surface could be coated or plated with something that either the solder or the flux doesn't like. It might also be corrosion, a lubricant, protectant, or who knows what. In those cases I clean it with a chemical such as electric contact cleaner aka brake cleaner, or even carb cleaner, but most people use alcohol. If that doesn't work then it's probably some kind of coating you'll need to remove with force, like sandpaper or a Dremel tool to break thru to the good metal. Once you've ground the bad part off, clean it, coat it with flux and try again.
If it's still being difficult you can try using sandpaper on it while it's coated in flux. I like 320-400 wet/dry paper, maybe 180-220 if it's really bad. Cut a small piece for sacrifice because you don't want to use it again now that it has flux on it. After you have either roughed it up nicely, or ground thru the problem coating whatever it was, clean it, flux it, and try again.
I prefer to coat the problem item in solder first, that way I know it'll work when it's time to attach something. Assuming the iron is hot, clean, and will hold solder (plain old rosin core 60/40 works best for me), put a little on the tip, then apply it to the surface and hold until it flows and coats your surface. If it's a large item and you can't get it hot enough you will need to preheat the item with a torch or whatever, I've used anything from little butane torches to my oven, as long as everything can handle the heat that is. (fyi; preheating also works for welding when the machine can't generate enough heat). Once it's hot enough the solder will flow nicely into the area worked on, and your problem is solved.

If you never could get the solder to stick then you might be working with the wrong metal, like aluminum, so use the appropriate method for that metal, or simply try using a screw or bolt as a contact. If you can figure out what the base metal is, then search the net for a bolt material that will not react with it. Example; drill a hole and use an appropriate bolt/nut and torque it down good, then apply solder to the bolt's head which should be a snap. Common steel bolts are usually coated with something which probably needs to be ground off. Grind off just enough area for what you need, and preferably solder it in a way you can still use the tool to remove it if needed. Now flux your spot and apply a little drop of solder like described above. Being a bolt it's probably heavier and may need a little boost with a torch.
I flux/solder each piece first so I know they're both good to go, then I put them together and add a drop of solder with the iron until it flows.

I hope this helps some people with their soldering problems...


I would probably avoid using brake cleaner then applying heat, because depending on the formulation you can emit phosgene gas:

Thanks, something to think about. I don't think you can buy that kind of brake cleaner anymore, plus it evaporates almost instantly when cleaning stuff like that. I do remember spraying the older stuff on something red hot and the smell was horrible. Not sure if it was that particular gas, but omg it was bad!

Speaking of solder, I lost my old solder and flux in a move so I bought this new solder and flux, some "safer" crap or some bs but it was all I could find. I haven't been able to solder anything but clean copper wire and that barely sticks together and often fails. It's horrible stuff. Maybe that was the original posters problem? I guess I'll have to buy some from china on ebay or something.

Lead free solder melts at 218 deg C where leaded melts at 183 deg C. You may need to get a higher wattage iron to work with it. That thanks to the EU which started this lead free mess.

I've always preferred a higher heat than what most people use, for example I won't use a 30w, only 40w at min. I don't know the exact temp but to get the same effect from the adjustable solder station at work I need 800F/426C. Others at work used 700-750F and they struggled. This was back when we used real lead and flux btw. So I don't think 218C would work at all, but whatever the case I'm well above it. I've even tried boosting the temp by heating my iron with a propane torch, but it doesn't help. My latest project needed tabs soldered to rechargeable AA batteries to renew a cordless tool batt pack. I've done this in the past with lead 60/40 and acid flux no problem, but the new stuff refuses to stick to the batts. It's like trying to solder to glass... Very frustrating. My flux might be part of the problem so I will look for a different type. I may have to spot weld the tabs like the factory does, but it doesn't help me with other stuff.

sand the battery contacts, and make sure the battery is getting hot enough. it's a very difficult thing to do, getting something like that hot enough without getting it too hot. also, reheating it over and over, trying to get it right, will probably negatively affect the battery life and capacity. practice on one set to know exactly what you need to do, before moving on and doing it right on all the rest.

Yes, I have done this many times for decades on all kinds of projects with no problems. Then I lose my old 60/40 lead and "good" acid flux and have not been able to solder a single battery since. I plan on trying spot welding next, unless I get lucky and find my old solder & flux. This new solder makes everything much harder btw, but it made the battery thing impossible.

A soldering iron is nowhere near hot enough to convert a chlorinated solvent to phosgene. Think arc welding or oxyacetylene temperatures.

Someone brought that part up because I said I used brake cleaner to clean parts that have grease/oil on them, then if the part is too big for the iron to heat you can preheat it with a propane torch. Not so much about the part getting too hot, but putting a torch on a the surface still wet with cleaner. Not a common circumstance, nor do I believe most cleaners sold today are an issue, but something to consider. Plus if you do manage to create the gas, which I think I might have once or twice, it's too nasty to breathe anyway.

my molten solder sticks to the soldering iron

clean it off extremely well, by tinning it and wiping it on the sponge. multiple times, if necessary.

or, you may simply not be getting the material hot enough. when the thing you're soldering is hot enough it will suck the solder off the iron. if you've never seen it, you may not believe it or be able to imagine it, but i promise you, it's like a sponge touching the edge of a water droplet... the solder literally gets sucked onto the metal when it's hot enough.

also, your iron may not be capable of getting hot enough, if it's really old or if the tip is damage in some way. if the tip is damaged, you could just replace it and see if that works. if the iron is so old it doesn't heat up enough, you'll just have to replace it.

jlandreth12 months ago
The iron I have is 20-140 watt. It also has quite a big tip so is this not as good for circuit boards? And also I always thought you had to tin the tip before and after using it. Is tinning it too much bad for it? Thanks

the big tip can work if you're careful. just don't allow it to touch anything other than the metal you're soldering.

i tin my iron every time i use it and possibly multiple times while using it, if it stays on a long time. once it heats up, tin it and clean it off on the sponge. it needs to be shiny. if it has discoloration, or isn't shiny, re-tin it and clean it off again on the sponge. through usage, you'll probably be getting plenty of tin on it, so you'll just need to clean it off every once in a while, but if it sits in the holder for a long time while hot, you will probably need to re-tin it and re-clean it before usage.

 I can't find a good suggestion (thanks for nothing, Google) for what table surface is best for soldering projects.  I don't plan on dripping all that much solder, but I want to know what common household surfaces are safest for my projects without incurring damage to the table surface.  I'm open to picking up a mat as well, if anyone recommends one.
I use a quarter inch thick stainless steel plate. It seems to hold up OK.
nprince pfred212 hours ago

Best workbench ever!

Use a large glass or marble chopping board/work surface for the kitchen. The ones used for preparing pastry are idea as they tend to be bigger. Glass ones will be toughened, so you don't have to worry about it breaking from heat or minor impacts.
Solder almost always has lead in it, are you suggesting eating lead is healthy for you? I'd just use a piece of plywood big enough for what I needed to solder on top of any surface.
I'm nut suggesting you solder in the kitchen, or use a kitchen work surface than you're then going to use to prepare food on. I'm suggesting buy a new chopping board, use it for soldering only in the workshop and not for food use. That should be common sense, which is why I didn't state it in my previous comment.
I'm thinking for most of us protecting our bench tops from soldering work isn't that critical. Any slight damage is certainly going to add the character of the shop. :) But seriousily the Formica surface of my old desk hasn't been hurt by hot solder that has ended up on it, though it has been subjected to large blobs of hot metal for any apprecible amount of time
Use a piece of cardboard, an old plank or a newspaper.
I use some scrap steel plate that came from the door of an old oven.  An old kitchen trivet or sheet pan may work well too.
may i reccomend a glossy ceramic tile? they stand up to the heat well, and the glossy coat doesn't melt and the solder comes right off. (if you drip some)

O.k., I didn't read all of this because of time constraints, but I'm really anxious to to so. If there is one thing I'm lousy at is soldering. I'm lousy at a lot of things, but this is a pain in my neck. I have one of those cold soldering guns that you can touch and won't get burned. Will your system work with them? I can't get the darned thing to work. See, I'm lousy at this stuff. I have regular soldering guns, too, and am geeked to get them do what I want. Thanks in advance!

using a candle to burn and melt is much easier

neutralityy3 months ago

If you have a old/not very good soldering iron and are having trouble getting the solder to melt by touching it to the component, you can touch the solder directly to the iron and make a "cold solder joint", but after it's on the wire, keep your iron there until you see the solder fill the cracks. This can work because when you touch your sodlering iron directly to your component, hea tis being conducted through a verysmall area, but if solder is completely covering your componenet and you heat up the solder, the componenet will heat up much faster.

Hi, what solder and soldering iron do you recommend if I just want to do some occasional wire fastening?

You may consider Atten AT-SS-50 iron, a 50w portable variable temperature control hot iron. it is a soldering pencil which is very light to handle. you can also control soldering temperature for various applications. best of all, it is very cheap in comparison to advanced soldering stations.

Thanks for the tip, I'll probably go with that.

Amazing information about soldering. This guide is really helpful to the people those who are in the basic level of soldering the electronics.

jardodonell5 months ago

i am great at dt

jardodonell5 months ago

I love chicken

belletinker11 months ago
Now I can make my own repairs once I get proper tools. Thank you, will save lts.
mfox141 year ago
excellent support and clear instructions helped me complete the circuit board job I was doing. repairing a He4t Washer. Thanks so much
Bompata2 years ago
How can I tell if there is hole in the circuit board where the pad is? Do I have to try to push a wire through while the solder is melted?
The hole should be visible. If, by chance, you're salvaging or attempting to repair something, then the hole may be "plugged" with the old solder, and perhaps even the lead from the old component. In this case, desolder the joint first (using a desoldering braid - which is my personal modus operandi - or a desoldering pump (which come in various forms, such as quasi-mechanical spring-loaded variants that resemble a large hypodermic syringe, or as a simple squeeze bulb).

Another tip, which is especially crucial when working on salvaged board/components, is to never 'reheat' solder in an attempt to reuse it. Once the solder cools and dries the first time, its "done". Don't reheat it in an attempt to 'reshape' it, or add more to it, just remove it and start again. Old solder loses many of its core attributes if reheated (and often goes from a shiny finish, on first application, to a more matte finish once reheated - stick with shiny).,
Pozole4 years ago
My Weller Digital instructions say to use DISTILLED WATER on the sponge.
sockless Pozole4 years ago
Round where I live, we have very hard water, but I still use it on the sponge, it doesn't really matter, if your tip gets calcium stuck all over it, just scrape it off with a knife or sand it off with some 800-1000 grit sandpaper.
Distilled water is a good choice, but not really needed. Depending where you live, you can probably pick up a 4 litre (1 gal) jug of distilled water for no more than a $2-4, and if you're just using it for soldering, it'll last you a fair while. Check pharmacies for it, and if they don't have it in stock, try a veterinarian supply or medical/home-nursing supply shop (I live in a somewhat small town, and there are three such stores within 10km of my house).

Some people use bottled water, but because with that, since most bottled water is "spring" or "mineral" water, which typically has a higher calcium PPM than tap water. When it doubt, read the label, but you *can* find distilled water sold as drinking water, and (other than the over inflated price of it in drinking bottle form), would work just fine.

You could always distill your own water with a simple steam condenser. There are no doubt many such tutorials on instructables regarding this - but the idea is to boil water, and then "catch" the rising steam and divert it into another vessel (by means of a tin foil cover over the boiling water, that has been 'channelled' to control the flow of the condensation).

I don't like the idea of using an abbrasive pad or sandpaper to clean the tip, unless you plan on replating it somehow... In Canada, we have a product called CLR that works great on that kind of stuff, and won't eat the tips plating at all (nor is it abrasive). It's ingredients include: Its ingredients include water, lactic acid, gluconic acid, lauramine oxide, and Propylene Glycol n-Butyl Ether; and is claimed to remove calcium, lime, and rust (thus the name, CLR). I make sure I rinse my tips after using CLR on them thoroughly, but other then that, they work (and look) like new!
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