Learning to solder

[TomDOW2]

I am a complete begginer at robotics. I am going to build the $50 robot, following the tutorial. This, and most things (as far as i can tell) in robotics requires me to solder.
I have never soldered before. The tutorial says that most solders will do but recommends a soldering iron that can have the temperature changed. As I have never made a robot before I would rather not pay the extra money required to buy a soldering iron that can change temperature (yet). I am thinking about buying this:

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Soldering-Equipment/Soldering-Irons/20W-Soldering-iron-with-fitted-mains-plug/73960

Would this be suitable for the time being (Once I am sure that robotics is for me I will buy a fancy soldering iron)?

Also, can I just buy any solder or is there a particular type that I should buy?

[GearMotion]

This will also help you: http://circuitgizmos.com/wordpress/?p=471

You should buy solder with a mild flux core. The solder should be for electronics work. Like this: http://www.mpja.com/prodinfo.asp?number=17462+TL or lead-free if you wish.

[tim_wang]

You do not need a fancy soldering iron. Just pick one with a fine (pointed) tip for soldering small components. Purchase resin core solder to make things easier on yourself.

Lastly, practice soldering on scrap wires before soldering electronic components.

[TomDOW2]

Thankyou, these will realy help. =D

[SmAsH]

Erm, 20W seems kinda low for hobby soldering... Try to aim for the 40-60 area.

[nottoooily]

Stay away from lead-free solder! It's a nightmare, and can require a hotter iron. Even with that it doesn't flow right. It's worth suffering a bit of alzeimers to get conventional solder.

[GearMotion]

Stay away from lead-free solder! It's a nightmare, and can require a hotter iron. Even with that it doesn't flow right. It's worth suffering a bit of alzeimers to get conventional solder.

Not from my experience. Nightmare? I don't even notice a difference anymore. Not to denigrate your experience, but with enough skill lead-free is fine.

Follow the directions in the link that I provided - cleaning and preparation are key steps.

[huevon]

Lead solder definately flows better. I personaly use 0.7mm Alloy 63%-tin 37%-lead. 63/37 is eutectic (the only mixture that melts at an exact point, instead of over a range)
It makes soldering easier than the standard 60/40. As the solder melting and solidification time is faster. Hence that allows you to use colder iron and lowers the risc of overheating a component.
But of course that's me, everybody prefers diferent tools and methods.

[corrado33]

Erm, 20W seems kinda low for hobby soldering... Try to aim for the 40-60 area.

Really?  I use a 15/30 W switchable one, and I hardly every use 30W.  I only use it when I I'm soldering a large pad or a component that sinks a lot of heat.  I feel the 30W just get's WAY too hot.  Just my personal experinece.  I can solder pads in a second when the tip is properly tinned at 15W. 

[SmAsH]

Hm, i started out with a 40W iron and now work with a 60W and love it.
Well, TomDOW2, maybe try out a few different ones and select the one you find easiest to use.
Also, maybe get a set of helping hands.

[corrado33]

Hm, i started out with a 40W iron and now work with a 60W and love it.
Well, TomDOW2, maybe try out a few different ones and select the one you find easiest to use.
Also, maybe get a set of helping hands.

Agreed, it's probably personal preference.  Honestly though, the best advice for soldering is to keep your tip cleaned and tinned properly.  A clean tip will solder MUCH better than a dirty tip.  Also, they have these little containers of (I think) small metal strips, you basically shove your soldering iron in them a couple times and they clean and tin your tip.  I've never used them, but I think they'd be extremely useful. 

[SmAsH]

These?
I have one and it is MUCH better than a sponge, doesn't damage the iron like sponges do...
But we're hijacking this topic so we better stop

[cyberfish]

They make 60W irons without temperature control!? Wouldn't that get way too hot?

I think 20W is a little too small, though, especially if you decide to switch to lead-free solder later on. They melt at a lot higher temperature. I use a 15W (from 10 years ago?) and it takes around 30 seconds to melt 1 lead-free joint... longer for bigger ones.

I would just get a 30W. They aren't much more expensive either, and will work with both kinds of solder.

By the way, a temperature-controlled soldering iron is nice, but really not necessary.

I am an electrical engineering student and do quite a bit of hobbyist work, all with a 15W iron (thinking about getting a 30W tho). We use 80W temperature controlled ones with nice LCD temperature display at school... but that's really just eye candy =P.

Sure it's nice to be able to heat it up in 10 seconds... but I wouldn't mind waiting a bit.

[GearMotion]

These?
I have one and it is MUCH better than a sponge, doesn't damage the iron like sponges do...
But we're hijacking this topic so we better stop

Those are great things and I recommend them highly. Back in the '80s, before I found these for sale, I made my own out of a copper scrubbing pad. I gave up the bad "wet sponge" then and I've never looked back.

[nottoooily]

Not from my experience. Nightmare? I don't even notice a difference anymore. Not to denigrate your experience, but with enough skill lead-free is fine.

Follow the directions in the link that I provided - cleaning and preparation are key steps.

Yea I only got 1 roll, and not bothering to treat it differently might have been my mistake Nonetheless, the only benefit it provides (AFAIK) is protecting artesian drinking water supplies from lead landfill leachate. Or because of the law.

[corrado33]

They make 60W irons without temperature control!? Wouldn't that get way too hot?

Oh... I see now.  I didn't realize you could have a high wattage soldering iron but manage the temperature.  Interesting.  I thought the temp of the iron was solely dependent on the wattage of it.  You learn something new every day!

[cyberfish]

If you leave the iron on for some time, the tip will come into equilibrium with air.

Think of energy balance.

Energy input is constant (60W), and energy output is how fast heat dissipates (into surrounding air or your parts).

Heat dissipation is proportional to temperature, so to dissipate more heat, the tip needs to be at a higher temperature.

High power is nice because it heats up your iron very quickly, and also maintains the temperature better while you are soldering (normally the temperature would drop because metal carries energy away faster than air).

However, without temperature control, if you just leave it there, the iron will heat up crazy and explode.

With temperature control, they can use higher power because they can turn it off when the tip reaches a certain temperature.

[corrado33]

However, without temperature control, if you just leave it there, the iron will heat up crazy and explode.

So when the power is less, like 15W, the tip has to dissipate less heat, therefore it will reach equilibrium at a lower temperature, so in theory, it's safer to leave a 15W on rather than a 60W.  Mind you, I unplug mine as soon as I finish soldering. 

[cyberfish]

Heat conduction is directly proportional to delta temperature IIRC.

That means, if a 30W reaches 400C (~375C above room temperature), a 60W would reach 25+2*375 = 775C!

It's not a matter of safety... I don't think you can even solder at that temperature. Chips will melt.

That's why I think something is weird here.

Do you have a link to your iron?

[amando96]

Erm, 20W seems kinda low for hobby soldering... Try to aim for the 40-60 area.

i heard 30W is the way to go for begginers, i am using a two year old 10 quid soldering iron from maplins, and super thick lead-free solder, i solder SOIC packages fine.

i advise you to practice soldering before moving to something easily damaged, like the mcu on the robot, get a broken radio, and practice desoldering, and soldering components on and off, if you do it well , and the copper doesn't get ripped out, it's cool.
remember to use little solder, it's easy to add solder, but a hassle to remove it, and after soldering rub the joints with alcohol to remove the flux, as it can corrode the board/solder with time...

[huevon]

When we talk about soldering, what fluxes do you guys use? I use rosin for viola. Ultra cheap, non corosive, but gives some fumes.

[vinito]

My soldering equipment saga is probably more of an anecdote than real cause/effect, so keep that in mind.
I used to use basic wattage type irons and you can do OK with them. But from the first moment I used a good temperature-controlled iron, the soldering experience was much more enjoyable and higher quality. As with any tool-using endeavor, better tools are more pleasurable to use. So I'd recommend to anybody to blow the money on a good soldering rig once you can afford it and you won't regret it. Shop around of course.

For me, the basic difference for a temp-controlled iron is the lack of waiting. The ceramic heating elements get up to temperature in no time and a temp-controlled station keeps it right where you set it. Basic wattage irons take a couple minutes or so to heat up, then change on you as you work. Often enough, I had to wait for the iron to heat up again after it got sucked out by a previous joint. On wattage, I'd say it's better to be a little too hot than a little too cold. A hot tip allows you to get in, do your work, and get back out quickly before the heat dissipates to everything around it. Thus the heat stays more localized. Too cold means you have to linger a long time and the heat sinks to a lot of stuff you don't need to be heated up. I'll defer the choice of specific preferred wattage to those with more experience.

Having said that, I do agree that the greatest success factor comes from a good tip! - meaning that a clean and properly tinned tip should work OK (and the shape of the tip to some degree as well), but a dirty or otherwise improperly prepared tip will cause grief no matter how cheap or expensive your rig is. I think that by the time I bought my nice rig, I simultaneously learned how to keep my tips in decent shape too, so that made a bit of difference in my success rate. I keep meaning to pick up one of those copper tip scrubber thingies but haven't done it yet, so even with a wet sponge I'm still getting decent results. Once I get one I expect that things will be another step better.

Personally, I only use rosin-core leaded solder. I like things to go smoothly and don't have any need in my work to suit anyone other than myself, and I don't do enough of it to feel I'm poisoning myself, that's for sure. Also, melting metal of any kind emits vapors of some kind or another, and I don't trust the government to know whether the new fumes are any better than the old ones until we've all been exposing ourselves for 30 years and it's too late. I do my best not to breathe it in anyway and I'd do the same with the new "safe" solder. There may be a day when a project warrants or even requires lead-free, but until then I prefer the ease of old-school technology. It seems to work fine for me.

When I need a dollop of flux, I just use yer basic rosin flux paste I bought from the local Radio Hack. I'm sure there are better products out there, but this stuff does what it's supposed to do and it was easy to find and not expensive. It's in my bench and I can use it when I need it. Some day I hope to experiment with some better flux - maybe the kind that doesn't need to be cleaned off? - but again I don't do a ton of soldering so for my low volume level the old-school technology works fine with flux too. In short, it does the trick and doesn't cause any major hassles for what I do with it.

$.02

[Soeren]

Hi,

To clear up what seems to be needing it, a temperature controlled iron of eg. 50W does not dissipate 50W all the time, it's just when the heater is on, which may be less than 50% with light soldering.

I'll say go for leaded "fuel" as well, the lead free (in which they just changed poison ) is not only hard to solder for a beginner, it really don't flow well and seems to crystallize all the time,  a few days ago, I just had to make repairs on a PCB that were soldered with unleaded and had to clean the entire board to get decent trustable soldering.
It just doesn't flow well and anybody feeling different is very welcome to make a video showing othervise!

Metal vs regular moist (not wet) sponges: I have both and for everyday work the metal "wool" is fine, but for precision work, I prefer the moist sponge, as it's the only way of getting the tip really cleaned up and remove every little blob - placed together, I can use whichever anytime.
Moist sponges doesn't ruin your tip, just don't use tap water for it, but get demoralized water and the tip will have a long life.
What really ruins most tips is bad care (and inferior tips on cheap irons).

For a non temperature controlled iron, 25W should be tops and may be a little too much for small components, but with experience comes the ability to do SMD with a 100W iron

[vinito]

"demoralized water"  
lol. I never runned across that one before. Sheltered life I guess.

Speaking of tips, here's one:
The electronics tech at a place I once worked wired a switch into the outlet that his soldering station was plugged into (switched outlet). He also wired a rotating beacon light into the outlet so when it was switched on, the beacon did its thing. It wasn't so bright as to be annoying in the well-lit shop, but obvious enough that it was a great indicator to signal that the soldering station was powered up, so it was actually difficult to forget to power the station down after you're done. At home I don't have that and I've discovered three or four times when I've forgot and left my station on overnight or even a couple days before I noticed it. Not good for the tip and potentially dangerous.

[Soeren]

Hi,

"demoralized water"  
lol. I never runned across that one before. Sheltered life I guess.

Oh well, very old joke in my circles, in fact so old that when someone actually call it demineralized water it takes an extra spin through the brain

Speaking of tips, here's one:
The electronics tech at a place I once worked wired a switch into the outlet that his soldering station was plugged into (switched outlet). He also wired a rotating beacon light into the outlet so when it was switched on, the beacon did its thing. It wasn't so bright as to be annoying in the well-lit shop, but obvious enough that it was a great indicator to signal that the soldering station was powered up, so it was actually difficult to forget to power the station down after you're done. At home I don't have that and I've discovered three or four times when I've forgot and left my station on overnight or even a couple days before I noticed it. Not good for the tip and potentially dangerous.

A similar tip saver (for mains operated non temp. controlled irons) is to wire a diode and a switch that is pushed open when the iron is in its holder. The diode is wired across the switch terminals to pass only half the periods and hence cool it down a lot while still having it heat up to working temp. in a short time.

[vinito]

That's a good idea too.
I was thinking about installing something into my station which would just beep every half-hour or something when it's powered up. In my house, that would probably be enough for me to catch it and keep me from burning the house down. Probably wouldn't hurt for me to have a spinning beacon as well. Cheaper than a new house.

As for old electronics jokes, I don't know if this is an old classic or an isolated incident.
Same electronics tech...
He said when he was in the Army, they would send a newbie to the supply room to get "a dozen BA eleven hundred N's on a string... Write it down green horn!". So he would, and then scurried off to the quartermaster to tell him "I need a dozen of these on a string" and hands him a note that reads "BAll00N".

hehe. Oh, I just love that one.

[Soeren]

Hi,

I was thinking about installing something into my station which would just beep every half-hour or something when it's powered up. In my house, that would probably be enough for me to catch it and keep me from burning the house down. Probably wouldn't hurt for me to have a spinning beacon as well. Cheaper than a new house.

A less annoying way might be to make a resettable timer, whether for half an hour or less.
If it has an array of LEDs going off one by one counting down, perhaps with the last one or two remaining set to flash, it shouldn't die on you while using it, but you'll never forget (or worrying about) turning it off then.

As for old electronics jokes, I don't know if this is an old classic or an isolated incident.
Same electronics tech...
He said when he was in the Army, they would send a newbie to the supply room to get "a dozen BA eleven hundred N's on a string... Write it down green horn!". So he would, and then scurried off to the quartermaster to tell him "I need a dozen of these on a string" and hands him a note that reads "BAll00N".

Hehe, never heard it before

There are lots of similar jokes/pranks that is thrown at "students" and while some of them is quite funny, some even with built in retribution, when they're sent to someone who don't like this "sport, I've never liked to do that to people who wants to learn. Besides the cruelty, it is very demotivating to be humiliated that way - and if not for the general cause of being kind to your students, at least the aspect that they may be the ones responsible for the tech. when we're retired, should make such pranks a little less common 

Not that I wanna ruin a funny story or nothing, but it's a bit like making fun of mentally retarded people or shooting fish in a barrel... Or shooting retarded students in a barrel or something like that.

There are two kinds of stupidity amongst students, the kind that just takes a bit of pedagogical teaching to cure and the kind that's "self inflicted" - people that just want to be spoonfed and still don't care to take it in. The first kind can be quite rewarding to get over the hump, the second kind... Go ahead with the pranks, or better yet, stuff them in a barrel and take aim 

But I digress...

[Admin]

I'll say go for leaded "fuel" as well, the lead free (in which they just changed poison ) is not only hard to solder for a beginner, it really don't flow well and seems to crystallize all the time,  a few days ago, I just had to make repairs on a PCB that were soldered with unleaded and had to clean the entire board to get decent trustable soldering.
It just doesn't flow well and anybody feeling different is very welcome to make a video showing othervise!

Well, you just need a hotter iron. I set mine to 350C when doing lead free, and it'll flow fine.

But there is no reason to use lead-free unless you plan to eat food off your circuit board, or sell your circuit in Europe. Lead-free is an expensive pain with no scientifically proven health benefit for adults.

[Soeren]

Hi,

Well, you just need a hotter iron. I set mine to 350C when doing lead free, and it'll flow fine.

I'm expecting a video soon then

Actually, the iron I use most of the time is a WTCP50 with #8 tips (= 800°F = 427°) with silver loaded solder or occasionally 60/40, but the one I used on the lead free recently was an iron made for lead free, with a tip going to 450°C (or 480°C), but no matter how high or low I set it, I got ugly and seemingly contaminated/crystallized soldering.
It might be that they have made the fluid_to_hard transition too short, as this will usually do that, or it might be that I added regular 60/40 (rosin core), but whatever i did, I'm not gonna brag about the result - a bit depressing after decades of soldering that has gotten highly praised by my peers.

But there is no reason to use lead-free unless you plan to eat food off your circuit board, or sell your circuit in Europe. Lead-free is an expensive pain with no scientifically proven health benefit for adults.

According to all the MDs I have discussed it with, humans cannot take heavy metals in in their metallic form. We are only able to assimilate it through the process of it being eaten by eg. a fish (in which it undergoes some changes to salts or whatever) which we eat later on.

My interest in this is not because I since childhood have hold the solder by my teeth and chewed it a bit, but more since I once took quite a sip of mercury, which I was playing with in a wine glass, while also having glass with wine - one should think it would be hard to mix up such things, as it was about half a red wine glass of silvery mercury (and anyone who ever played with large amounts of mercury knows it's real heavy), but I succeeded anyway.

So, if I seem mad as a hatter, perhaps the MDs are wrong 

[cyberfish]

At school we use 420C (80W station) with lead-free (not sure what exactly though, it's supplied by school), and it works pretty well. Takes a bit longer to melt, but no flowing issues.

Sorry no video .