1. What is Soldering?

In a recent thread, yet another discussion about soldering tools and techniques prompted me to propose a blog on the topic.

At least one person said they'd read it, so I have started it. The goal is to create a resource for the AAC community that can be used as a reference. The hope is that there will be participation from the community in creating to refine and correct it as necessary. I would greatly appreciate comments, corrections, additions, and advice.

From the description:

For an electronics enthusiast, soldering goes from an occasional activity to an essential skill.

Hand soldering, like so many things, is both art and craft. There are things that one learns to do by experience that can be hard to teach directly, that's the art. There are other things that provide the foundation for a successful application of the art, that are based on an understanding of just what soldering is, how it "works", and what physical things we can, should, or must control for the art to be successful.

The purpose of this blog is not to be a comprehensive treatise, rather it is to provide a roadmap to the beginner so the path to success in hand soldering is laid out at least in mile markers that will allow personal exploration of the other information that will lead to expertise.

It is my belief that true expertise in anything, but particularly in a field like electronics begins with some understanding of the physics involved. In this way, the behavior of the materials and structures we are trying to fashion into something useful can be better understood and predicted. To that end, the first post in this blog will be about the nature of soldering—something which is often overlooked, even by people who have been successfully soldering for many years.

The subsequent posts will cover materials and tools, including:

Solder Wire; its types and alloys
Fluxes; and why to choose one over another
Soldering Irons; their taxonomy, application, and qualities
Techniques; proper preparation of the parts to be soldered, and application of solder wire, flux, and heat
Related Topics; including things like solder pots, preheating, and the like

This is a (somewhat) ambitious project because although I don't expect to produce a definitive guide, it is my hope that with contributions from readers and the many hundreds of years of cumulative experience, corrections, emendations, and additions can be made to polish the information to the post there is nothing important missing and nothing misleading.

I hope you will read and contribute to make this a resource for everyone on AAC no matter what level, we all have something to learn.

This first installment covers basic information on the nature and purpose of soldering. Please read it if you are so inclined and comment on the good and bad you find. Thank you.

 

UPDATE: I‘ve got a various parts of this series as research notes and drafts. I am revisiting my blogs posts and this series is on the list for some attention.

This is a fairly large undertaking, if done properly and while I don’t currently have things organized well enough to start I would be very interested to know if anyone would like to contribute. This could be by research, writing, technical editing, or some way I can‘t think of at this point but maybe you can?

If you might want to collaborate please let me know by replying to this post. All I‘m trying to do right now is gauge interest, so this doesn’t represent any sort of commitment by either you or me. It’s about first pass planning.

So, if you have any notion at all that you would like to be involved please reply without fear you are making any sort of promise to do so—I will be working out details later and then you can choose to commit to something or just choose not to. (And you won’t even have to claim that someone hacked your account and posted it without your knowledge!)

Also, if you have some novel idea about how you might contribute, please do mention that in the reply. I am not only open to ideas, I really want to take advantage of the diversity of thinking here so at this point all suggestions are welcome.

Thanks!

—Ⓨ

 

I have an extensive amount of soldering experience, and I did write up a document about soldering for a friend who had taken a course in welding but had no clues about soldering. If I can find that document it could benefit those who are starting at the beginning. The one insight that I would share with those starting is that solder conducts heat at least a thousand times better than air, and so a bit of solder in a joint will allow proper solder melting and flowing without excessive heat application.

 

You probably won't take this as being something to think about, but please do. Don't do what you usually do when talking about how things are done, by saying that only the most expensive and esoteric(to the general public/members) are necessary to do the work.

In your normal posting you always talk about the high dollar tools or what ever you have and use to do things. We are not all wealthy.

I do not recall ever saying that about tools. And as a matter of facts, I do quite good soldering with the very cheap ring pencil tools, as well as soldering bigger stuff with the 30 year old 150 watt iron. What is useful for good soldering is a means of adjusting temperature.That works with a lught dimmer and an outlet in series in adouble electrical junction box. About as cheap an adjustable temperature rig as there is. But itis needed to have good quality solderand flux. Radio Shack solder was good, so is the Kester brand..

Probably he is talking about somebody else, my last 3 soldering pens cost less that $10 each, one was $4.95.

 

MOD NOTE:

@shortbus: Your concerned about cost issues was made and acknowledged. It's up to @Ya'akov as to whether, and how, to address them in his blog. If anyone feels they are not addressed adequately, it can be seen as an opportunity for their own blog entry, perhaps Soldering on a Shoestring. So, please, let's consider this point addressed.

 

With soldering skill, practice is a major element. One extra source of practice is UNSOLDERING parts for salvage. That practice helps in developing the feel for melting the solder,which is important, especially on printed circuit boards. Not all used parts are trustworthy, but consider that heat sinks do not fail, and they are quite useful when needed.

 

On an allied note on the manipulation of solder, in my early stages of career, I saw a lucrative opportunity arise where many older homes in the UK that hot water tanks that were heated from a coal fire boiler.
The opportunity suddenly arose for the conversion of these copper tanks to Electric Immersion Heaters.
One hitch, it required the soldering/sweating in the tank of a brass flange. I went to one of my friends who at that time was a plumber, skilled in the art of wiping a joint.
He proceeded to give me a crash course,
This skill has kept me in good stead over the years in the manipulation of solder.
(I did balk though at obtaining a mole skin for wiping}



.

 

it required the soldering/sweating in the tank of a brass flange. I went to one of my friends who at that time was a plumber, skilled

I do very much enjoy sweating plumbing fittings, but I’ve never had to work on lead, only copper. I always say that I love to do plumbing, so long as it is new plumbing. Working on plumbing that has been around for a while, is not my idea of fun, supply lines are bad enough but water lines can be a nightmare.

Sweating copper joints takes some practice to do well, the results can look very nice which is very satisfying. (Particularly when they don’t leak.)

 

Sweating copper joints takes some practice to do well, the results can look very nice which is very satisfying. (Particularly when they don’t leak.)

The art has pretty much died out, but the work I was used to seeing with the old timers,, you would swear it was turned on a lathe!
Plumber from the French for lead, Plomb!

 

I have the same feelings as Ya’akov. I had a rental property that was almost 300 years old, which had been modernized several times. Repairing THAT plumbing was a bear. Plus. I built my own vacation home and did all the finish plumbing myself.

Now, the technology has totally changed. Plumbing isn’t even metal anymore.

 

Indeed!! The non-metal plumbing certainly causes problems where the metal pipes were used for the safety ground connection. I have fought with that in one home where the main ground connection was maintained to a six inch chunk of steel pipe. The result was a lot of electrical noise issues for the HAM operator who lived there. Unfortunately that person has less electrical talent then the average cat.
Now I am faced with the challenge of replacing all of the steel cold water lines in my home. PEX, or similar would be easiest and probably the cheapest, but it is a reasonable insulator. So this means a long run of heavy gage cable from the breaker panel to the water supply entrance point. I am not sure if I need to make it adequate to carry a portion of a lightning strike, or only the current described as our rated max load current by the supplying utility company, given that fault currents only flow until the protective device operates.

 

Now I am faced with the challenge of replacing all of the steel cold water lines in my home. PEX, or similar would be easiest and probably the cheapest, but it is a reasonable insulator. So this means a long run of heavy gage cable from the breaker panel to the water supply entrance point. I am not sure if I need to make it adequate to carry a portion of a lightning strike, or only the current described as our rated max load current by the supplying utility company, given that fault currents only flow until the protective device operates.

You can still use copper pipe for your ground, you just won’t be running water through it.

 

I am not sure if I need to make it adequate to carry a portion of a lightning strike, or only the current described as our rated max load current by the supplying utility company, given that fault currents only flow until the protective device operates.

Here for a residential earth conductor from panel to incoming side of the water meter is wired with 4_AWG stranded. For 200amp service.
The alternative is two ground rods, spaced 6ft apart .

 

Here for a residential earth conductor from panel to incoming side of the water meter is wired with 4_AWG stranded. For 200amp service.
The alternative is two ground rods, spaced 6ft apart .

Thanks, Max. I do not have200 amp service, and so should be able to use a couple sizes thinner. Using plain copper pipe fora ground connection is an interesting concept indeed. I could make the run from the meter to the branching area near the water heater using3/4 inch copper, and then change to PEX for the rest of the distribution. But I have heard some folks complaining about copper contamination in water, which makes no sense except that copper is bad for trees and tree roots. At least copper sulfate is bad for tree roots.

 

With soldering skill, practice is a major element. One extra source of practice is UNSOLDERING parts for salvage. That practice helps in developing the feel for melting the solder,which is important, especially on printed circuit boards. Not all used parts are trustworthy, but consider that heat sinks do not fail, and they are quite useful when needed.

Could not agree more here. I spent a lot of time scavenging parts when I was young and broke. Learned alot about how to manage heat and deal with LF solder. By the time I was starting in the field professionally, SMD part soldering and rework were not much of a departure. This skill is sometimes a long learning process for younger coworkers.

And yes, I still have my little plastic boxes of used parts that get rummaged through from time to time for a prototype.

 

The secret of a good solder connection is having the materials to be joined hot enough so that the melted solder can wet their surface, instead of freezing against it. And that is where a number of instruction texts go terribly wrong, in saying to not apply solder until the joint is hot. That will take quite a while if the contact is only a point contact. That is where the addition of just a bit of solder provides vastly better heat transfer, allowing almost instant heating to the required temperature. At that point more solder can be added to fill the small voids, and the connection can be allowed to cool.
It is the transfer of heat energy from the mass of the soldering iron (pencil tip) that does the heating, not the high temperature, So hotter seldom helps, if the mass of the tip is adequate and the connection of the iron to the joint is completed with a bit of solder to rapidly conduct the heat.
So the condition of the soldering tip is very important indeed. The surface must be able to be wetted with that thin layer of melted solder so that the rapid transfer of heat energy can happen. That means that attention to keeping the tip clean is important.
The problem is that at the higher temperature most materials oxidize and that leads to forming a layer of insulating mmaterial that must be wiped off frequently.
(At this point others can add their comments.)

 

Curious I am working once a week at German-Latvian adult education center to teach a soldering techniques. So, may ask anything!

One thing sure is too small advertized is mouse trap. Mouse trap is used to solder SMD parts in no respect multi-feet of two/three feet. The very core of problem there is that right hand keeps the solderer, left hand is manipulating with tin wire, but third hand must keep the SMD component in the right position. And I always have a deficiency (dont know how You) of one that third hand. So take the mouse trap that spring type and cut to the half longitudinally. So the spring one end is exerting from the wooden plane, axis is fixing the hinge to thiis spring coiling, and the free end must be rather long and rather strong (about 0.5 kg) with sharpened end looking into wooden base in 90 deg angle. Put under it the PCB, put on it the SMD component, pull the needle (spring) on it and with appropriate instrument (sharp-end pincette of thick handle needle) move this component precise in position what microscope shows is good. Then apply the existing two hands to solder it.

 

Curious I am working once a week at German-Latvian adult education center to teach a soldering techniques. So, may ask anything!

One thing sure is too small advertized is mouse trap. Mouse trap is used to solder SMD parts in no respect multi-feet of two/three feet. The very core of problem there is that right hand keeps the solderer, left hand is manipulating with tin wire, but third hand must keep the SMD component in the right position. And I always have a deficiency (dont know how You) of one that third hand. So take the mouse trap that spring type and cut to the half longitudinally. So the spring one end is exerting from the wooden plane, axis is fixing the hinge to thiis spring coiling, and the free end must be rather long and rather strong (about 0.5 kg) with sharpened end looking into wooden base in 90 deg angle. Put under it the PCB, put on it the SMD component, pull the needle (spring) on it and with appropriate instrument (sharp-end pincette of thicj handle needle) move this component precise in position what microscope shows is good. Then apply the existing two hands to solder it.

Sticky flux can be a solution to this problem. It works very well and allows you to position the part, then solder it while it is initially held by the flux.

 

For mass production systems I have seen where the PCB is first printed with the solder paste. Then a small dot of adhesive in the center of where each component will be placed. Then through the machine where all the surface mount parts are placed, and then into the reflow solder oven, where the solder/flux paste is melted and all of the parts are soldered in place. But with the adhesive attachment the assemblies are not repairable because of the adhesive bond being very solid.
So service on products made with that process is to replace the assembly.
When I assemble surface mount boards I tin a connection pad for each component, and then place the component on the pads correctly. Then, while holding the component in place with a tool, I heat the solder-tinned pin, and that holds the part correctly for the rest of the connections. This method works for single units,it would not be good for production. But it allows a prototype to be created quite well.

 

There was some discussion about the lack of separate words in other languages for "solder" "weld" and "braze".
I like this from AliExpress: