Hi welcome to the Eev blog an Electronics Engineering Video blog of interest to anyone involved in Electronics Design. I'm your host Dave Jones Hi Ever since day one, by far the most requested thing I get asked is Dave can you do a Blog on soldering? All right? Here we go: Everything you need to know about basic soldering. Let's go now. Good soldering technique, contrary to popular belief, is not hard.

In fact, it's incredibly easy and it doesn't take years and years of practice to get good at soldering. If you got the right tools and you know the very simple basic techniques, good quality soldering is a piece of cake. Anyone can do it straight up. not a problem.

In fact, it's actually incredibly difficult to solder badly. So let's start out with the correct tools that you need. and and here's a basic soldering iron kit. You need to give you top quality, professional results and we'll go into them all in more detail.

But basically you need a good quality temperature controlled soldering iron. Need a pair of side? Cutters You need? uh, this a good specific type of solder which will go into you need some solder Wick To clean some stuff up, you need a pair of tweezers for SMD work. You need a couple of different types of Uh tips for your soldering iron. You need some magnification to inspect your work afterwards and you probably need some additional flux as well.

I Use a flux pen for that and there's a couple of more items as well if you want to. uh a SMD hot air? uh rework? Uh, station is very handy as is a second soldering iron. As you can see I've got two soldering irons permanently set up on my bench. very handy.

You need goggles eye protection because Solarint can be dangerous. As with the fume extractor as as well. you don't need a full-on fume extractor, but just a simple 12volt DC Fan that that just blows across your desk to get rid of the fumes. Now, when it comes to selecting a soldering station, you do not need anything more than a basic this basic Heo Fx8 soldering station.

I Highly recommend. Uh, this one. It's only like 80 bucks or something. There's no need to spend more now.

It's a nice small uh footprint on your bench. Like this. It's a quality brand name. Hoo Uh, they they are renowned in the industry.

Do Not buy a no-name brand solder in station. You will regret it. Stick to the top brands. Hoo Weller Pace Ura Um, you know there's a quite a few uh, good top quality names around.

Ask around on forums which is the best. This Hoo is all you need. now. It must be variable temperature.

Do Not get those ones which rely on changing the tip on here to change the temperature like some of the Old Weller ones uh do are are classic. For that, they're not nearly as versatile as this. Get adjustable temperature. Do Not buy.

Please Do Not buy those fixed. um uh. plug in they they. They're just Maines They're basically a soldering um Iron like this that plug directly into the mains.

They are just garbage. Get yourself a good quality, professional, top brand variable temperature soldering station and I highly recommend ones with the separate stand. Just like this one, you can move it anywhere on your bench. It's very flexible and it's got several different types of uh soldering cleaning options.

It's got the classic uh wet sponge you just uh moisten the sponge which will go into and it also comes with this gold uh cleaning stuff in here which you just insert your tip like that and you can clean it. It's actually coated in flux and it wipes them and it doesn't uh therm, um shock the soldering IR like the wet sponge does and it's got this uh, sort of like rubber coated thing here that you can just wipe off components if you've actually removed an SMD chip or something like that still stuck on your iron. Just give it a little wipe on there or on your sponge so it's really good. Really handy.

You can move it around your bench that's what you need and you're going to need a good pair of flush side Cutters for cutting off uh, your component legs after you sold them. This is perfect exite made in the USA ones. absolutely spot on. They're under 10 bucks you can buy them for and the most important criteria is to get one with a flat a flat face like that.

It's hard to get on the camera there, but you want something with a flush. that's why they're called flush side Cutters They're completely flat surface on the back. It allows you to get down and cut right at the base of the joint. and you need some soldering iron.

Wick to Wick away solder from your joints to clean them up. Uh, rework all sorts of stuff like that. Get a good quality brand. Do not get the cheap.

Brands This is a top quality professional multicore made in the USA brand. Um, you can get them in different widths like this. It's got flux built into it. This is what you want I Highly recommend you get some uh, finer stuff like this.

You can even get finer than this. um plus some wide stuff. just uh, just have a and you go through this like there's no tomorrow. So make sure you have more than a couple of reels of this on hand and in addition to your solder.

Wick I Recommend you just get one of these. uh, vacuum pump. uh solder suckers. You push it down and bang.

It just sucks up the sold up from the board. They work out reasonably well. You can actually get, um, electronic pump versions of this, but um, these are only a couple of dollars. Very cheap.

Highly recommend you get one Now when you're working with Uh surface mount boards in particular, you're going to want some Vision equipment now. I Showed before one of these. Jewelers Loops Great for inspection, but you can't really do soldering under those. They're just adequate for individually inspecting each Uh joint and you can get away with that.

But if you're doing say 0402 uh components or um, something smaller than that or .5 mm pin pitch components you might need. Well, this is a top-of-the-line um stereoscopic microscope. Um, you don't have to get one of this. This has got a range of 8 times to 40 times magnification.

but uh, something cheap and simple like this. um. illuminated magnifier. You can actually switch it on here and and it actually lights up the board under test and this is only Uh 2 and 1/2 times magnification.

It's got a little insert there for five times, but that is really, uh, good enough for uh viewing. uh, boards up, uh, actually soldering under the boards because there's no outer uh ring on there to sort of uh to actually get in the way and and distract your view. and it's uh, it. It is actually quite, um, adequate for a lot of Uh uses.

So something like that, uh, you can get these, um, more inspection magnifying uh type devices that's actually from a very expensive mantis uh scope and a lot of people will use these headband magnifiers. They're you. You stick them on your head and uh, they're like a they're like a pair of magnifying glasses. um I don't like those myself, but um, some people swear by.

but uh Vision equipment like this that you solder under. you can get some one of those Maggie lamps or something like that. But for soering something like 2 and 1 half times absolute minimum you want for uh, for good detailed work uh times four I would actually recommend or times six and for really fine stuff. uh, fine soldering.

uh probably 8. So that, uh, anywhere from 2 and 1/2 time 2 and 1/2 to three times to time 8 is the range of magn ification that you're going to want for fine SMD stuff. Now one thing you might want is a PCB holder to actually hold the board in place while you solder it. And there's many different uh devices available.

Cheap ones that have little um, alligator clips on them that just hold the board and uh, big pan tilt heads that actually, um, move the board allowed you to move the board to any angle and flip it over. and um, a lot of people swear by the genuine Penice brand and stuff like that. Me: I personally prefer just the freedom of just having the board on the bench, but it's uh, sometimes handy to have, um, some way to hold the board. Um, some people actually prefer to solder them up in the air, actually raise the board.

up off the bench, and uh, solder it that way so that they're closer to it. Um, I Prefer to have the higher bench so that it comes up higher towards me anyway. but uh, yeah, each to their own. um, a board holder? Certainly, you won't waste your money on it.

Now, a good pair of tweezers is absolutely essential for surface mount work. Now the two requirements are: I Highly prefer the ones that are just straight like that. They're not, uh, curved. You can get ones that bend up at the end like that.

You can even get like entire sets like this that have, uh, different different types of, uh, tweezers. And they're okay. But really, this will do, you know, 95% of work. It should have a reasonably wide opening there so that you can actually grab chips and things like that and hold them in place so you can actually force them open.

It should be stainless, seel, nonmagnetic, uh type. This is actually a Cnk brand one, so it's a good quality Uh brand and a nice fine sharp tip on it That's absolutely essential. And you can do components, um, down to 0402 or smaller sizes with a pair of SMD tweezers like that. Now it can be really handy to have some additional form of flux.

You can even get it as a flux pen like this. This is a top quality Electral Lube Uh brand one. Really awesome. They're You know they're not that expensive I Highly recommend you get one.

or you can get stuff. um, which is a paint on uh, in a in a bottle and it's actually a full-on liquid and you can brush it on onto your board. But flux as we'll go into is quite important to have. Now without a doubt, the most important thing for good quality soldering is good quality solder of the right type and the right thickness.

This is the biggest tip I can possibly give you for getting good quality soldering results. Use the finest solder you can the smallest diameter I use 0.46 mm diameter I re highly recommend sticking under .5 mm or 0.02 in or 20 thoul solder. get that or smaller. Also have some really thick 1 mm stuff on hand or something like that just for bigger joints.

But the biggest problem beginners make um, when they're soldering is to feed too much solder onto the joint. If you've got really thick solder like 1 mm solder, it's very difficult to control the amount of solder that goes out of the joint. The finer the solder in wire you have, then the better quality results you'll get Because you can control the amount of solder which goes onto your joint. It's vital.

please do not get huge solder. Get this fine stuff. even if it cost you 20 or 30 bucks. Buy a roll of this stuff.

Now there's a couple of different types of solder available. Not talking about the width anymore I'm talking about the Uh composition of the alloy now. I Will not recommend Uh for this tutorial. Will not recommend at all.

Lead Free Solder that is more Troublesome I Highly recommend you just stick to regular lead solder actually F your Technique on on lead based sold up because it's easier, it's cleaner, you can get experience on it and then if you want to later move to lead free solder. but stick to lead. Now let's look at this. There's many, many different types.

There's more than types you can poker stick at, but these are the three basic types. The one I've got here is what's called 6040. This one has been used for donkey years. It is your traditional solder.

You can't go wrong with 6040 Uh. lead solder. Now what that means, 6040 is the ratio. It contains 60% in this case SN which is tin so 60% tin and 40% PB which is lead.

If you know your periodic table there the symbols for them. Uh, now this is the one I use here only because I don't have um I don't have any of the Uh 6337 type at home. that is the more modern type. If you got to buy some I'd probably recommend the 63% uh 10, 3 7% lead.

it's more modern now. The differences between the two is a slight difference in the Uh melting point of them, but practically nothing really. Um, and but the main difference is is that the traditional 60/40 type actually does not melt at one specific temperature. It actually melts over a wider range of temperatures or What's called the plastic region and it goes by various other uh names and uh, that means as um, it doesn't perform as well if your um if your solder joint cools down slowly whereas the more modern type the 63% 37% uh type.

That stuff actually melts at one specific temperature only and it doesn't have any plastic region or any other nasties with it. It just it just either goes from solid to liquid or back to solid at one specific point. That's it. So highly recommend you get that one, but 60/40 is fine if you get that too.

Now there's another type which I've got here. which um, you can't really read that label anymore. It's a bit worn, but it uh contains 2% silver. AG Uh is the symbol for silver now uh.

The reason for this is because a lot of Uh surface mount components like surface mount capacitors and things like that the end caps used on on them will actually contain a little bit of uh silver in them. Not always. but uh, they have been known to have that and having silver or what's called silver loaded solder like this can be useful or um sometimes essential for Quality Um, You know when when you start talking really professional, quality production stuff at at at home? it doesn't matter at all. Um, but you just have to be aware that there is, um, some silver loaded solar available for SMD work and things like that.

But I don't really recommend that you get that. stick with 6040 63, 37 and you'll be right. And the other thing you have to get in any solder is a multicore flux. There it is.

This type is a five core. Inside this tiny little 0.46 mm diameter um solder is actually five cores of flux type 362 flux. We won't go into that doesn't really matter what type for basic soldering like this, but you must have solder multi-or solder with flux in it. Do not use anything else.

You'll get absolutely crap results. and as usual, there's many different available. If you can, just read that it says low residue, easy to clean flux. This just has like a smart uh flux in it that doesn't leave much, doesn't leave much uh Flex flux residue on the board so there's less clean up afterwards.

Many different types, more types of flux than you can poke a stick at. Now, when it actually comes to flux, there are pretty much two basic types. One is your traditional Rosen based flux. so if you read uh, on a data sheet or something, that solder has a Rosen core in it, that's actually the flux.

It's um, it's actually a Sap which comes from a pine tree. so this one's actually a five core. So inside, there is actually five cores of Rosen uh flux and the uh low clean, the low flux varieties, and the other uh, low clean ones. They they're actually a new water soluble, uh based flux because, uh, Rosin's actually bad for the environment and all that sort of stuff if you burn it.

So, um, yeah, moving. They're trying to move to these water-based fluxes. but either Rosen core works perfectly, as do the new waterbased ones. So either one, as long as it's got flux in it now, it seems like I've crapped on there forever about using the right type of solder.

But trust me. Absolutely essential. Thin, 6040 or 6339 and multicore flux and top quality brand. Please, nothing else.

Don't come winging to me when your soldering crap because you're use the wrong type of solder. and if you're going to be doing Advanced SMD work, you might want to get into solder. Pace You don't have to. You can do most things with just regular solder.

Regular solder is easily easier actually. um, uh, but solder paste can be very, very useful for a lot of things. If you want to get into it, it's got a little nozzle. The only disadvantage with this this is a 63% uh tin one.

uh, the only disadvantage. and it's got flux building as well. But the disadvantage is that you have to keep it in in the fridge otherwise it goes off. Uh, you've got to let it warm up a bit to room temperature before you use it and it does have a shelf life.

So lots of disadvantages to solder paste but can be essential. Now when you buy a soldering like this Hoo Fx8, it will typically come with what's called a conical tip. Now I'm rotating that soldering iron there and as you can see it's got a round. It's got a a pointed tip on it like that.

These are really really no good at all as we'll go into just really throw these out now. Um, you can get I I Still recommend. Uh, keeping one. maybe a finer point one like that.

But really, you think when you're doing surface mount work that one of these really fine point ones is the only option? Well it's not. The reason being it that they don't work is because they do not have the surface area to transfer the heat to your particular components. Now granted, I would recommend as I said I'd Recommend having one of these fine point tips just for the occasion when you absolutely cannot get in cannot physically fit in the other type of tip. I Recommend which is the Chisel tip.

Now this is what you want for uh, general purpose soldering through hole and surface mount is what's called a chisel tip like this. As you can see, it looks like a chiseled wedge and they come in different diameters. but uh, this is is a just a very basic uh one which you know that's a 2 mm diameter or something 2 and 1/2 mm diameter. That's fine.

Maybe you can get them down to 1 or8 mm or something like that. This one here is slightly uh, wider, but that's really all you need to uh get top quality results for both surface mount and through hole soldering. And there are other weird types like this bent one which can be occasionally hand for getting into very difficult locations. And there's a bent uh chisel type.

In fact, it's really not a chisel cuz it doesn't have a flat uh point on the end. it's really designed for like getting onto a surface or something like that. and there's a really there's another uh wedge CH tape shaped uh chisel type one like this. they they got very obscure applications.

You don't need those for general purpose, just stick with your generic uh chisel Point like that which is reasonably fine on the end and reasonably narrow. Two different types of those plus one of those fine point conical. the other type of tip you're going to need if you do a lot of surface mount. uh, soldering is what's called one of these well um or wicin solded tips.

As you can see, it's a sort of like a flat end and it's got like a well, in there. And uh, how it works is that you fill that with solder. Uh, just just above the surface or so. It just bulges out the top and then you can drag that along the pins of your surface mount component and it works.

Almost like magic. It will, uh, it will only apply the amount of solder onto the pad that the pad needs and then it will Wick the solder back into there. it it. Trust me, they do actually work like magic.

Highly recommend you pick up one of those for good quality and quick surface mount soldering. But if you can only get one tip, make it one of these wedged type ones. They're useful in probably 95% of soldering applications. Now, just another mention of soldering safety.

Uh, you really should be wearing a pair of safety goggles specifically for uh, rework. Uh, mostly. when you're uh, solder can actually Splash and it can actually Splash long distances and it can end up in your eye and you don't want to lose your eyesight. Okay, if it ends up in your lap and it burns your leg, Well, everyone does that right.

You learn the lesson the hard way. The other thing is a fume extractor. Okay, this one's got a um, it's got a proper charcoal impregnated filter in it, But uh, these, you have to actually solder very close to the work. Otherwise, the fumes just go straight up and they don't actually get uh sucked into the exhaust fan.

So with even with this a lot of the time I Just turn it around backwards like that and the fan actually just, uh, blows out the back and that's good. If you're in a ventilated room, it's better just to put a small fan. just a little mini desk fan on the side of your desk and it just blows the solder smoke away the solder fumes. Now, contrary to popular belief, you don't get lead poisoning from the fumes.

It's actually the flux in the solder that we looked at. That flux? That's what you're actually breathing in and that is quite dangerous. It causes asthma and all sorts of other nasty stuff you don't even want to know about so really should not be inhaling those fumes. and uh, as for uh, lead and lead poisoning? Well make sure after you sold it, you wash your hands because it's uh, you don't want to just go eat something after that.

The only way you're going to get lead poisoning is not through your skin, just handling unless you got a direct cut or something like that on your hand. It's if you then rub your eyes or your nose or something like that. or you go and eat and you actually ingest the stuff. That's when you get the lead poisoning.

But apart from that, it's pretty safe. A Lot of people including myself if I know I'm going to do a lot of soldering I'll use a pair of disposable gloves. Now, if you go, look up the properties of uh, Standard 6040 or 63, Uh 37 uh tin. Le Solder, You'll notice that it melts at about I Don't know about 180 190.

Now you'll notice that this soldering doesn't even go down that low. It stops at 200 C or just under 400. F Now why do we need to start from there and go all the way around to 480 or 9 C or 900. F When the solder melts at around about this point under 200, that's where it actually transitions well.

The main reason for it is the thermal capacity of your solder. Yes, this tip here will actually regulate at that temperature. So if you've got it set to 350 and you just sit it there in free air, yeah, this tip will regulate pretty close to that 350. Now, it's much higher than the melting point of of standard solder.

So why do you need it that high? Well, it's a thermal capacity of the iron when you touch, uh, this onto a piece of metal. Then it transfers or sucks heat out of the iron. and it can't. You know? Unless you've got you know, huge amount of energy being pumped into there.

It's hard to get that energy into a small area like that and it cools down. So uh, really, you need a higher temperature on your soldering IR than the melting point of solder because when you put it on the joint, especially if you got large components, that component will cool down your soldering iron to the point that's actually, um, that the solder will actually melt and it will work. And this is why components are actually designed to survive. Uh, reasonably high temperatures like 400 C or 380 C for 10 or 20 seconds or something like that.

They can easily survive those sort of temperatures when they go through re flow ovens, which we'll have to mention that's different to, uh, hand soldering things. But now, what temperature do you need to use? Well, I'm glad you asked. and around 350 C is a pretty good uh Baseline for general purpose uh, through hole and SMD soldering. If you got some really big, beefy, uh components like To220 packages and you're trying to sold it at the tabs on those, you're trying to soer heat sinks to boards or whatever, you might want to ramp it up to 400 Celsius Or you know, or if you're talking Fahrenheits if you get one of those fixed temperature irons, you would get a 700 degree Fahrenheit iron.

So that's a reasonably, you know, anywhere between 350 and 400. Generally speaking, you don't really want to go over 400 unless you're talking uh, lead free solder and various rework scenarios and things like that. But somewhere within that range is pretty much what you want for general purpose solder and really, under that, um, you're You know, if you've really got some very temperature sensitive, uh, components that you know and and you don't want to thermally shock them, you know they're very sensitive to uh, temperature. You might turn it down and uh, you know, to 280 or something like that under 300.

And uh, it'll take it longer to uh solder. Perhaps depends on the thermal capacity of your soldering IR But that's a um, safer area to work with. Also, you can get clipon little heat sinks for through hole components. You can actually put those heat sinks onto the legs of the component and they will actually cool them down.

So there you go. That's basic soldering. Tools In a nutshell, why do I have to spend 30 minutes talking about it? Because it's important. If you don't have the right tools, you're not going to be able to solder properly.

Doesn't matter. You can get the world's best solderer. If you give them crap, solder, and crap tools, they're going to do a crap job. You need the right tools to do the right job.

So in part two and part three of the tutorial, we're going to actually do some real soldering. Put these tools to use. See you next time!.