Learning How To Solder
My son is beginning to take a real interest in electronic circuits. As a ham, I should feel uniquely qualified to show him the world of radio and electronics.
But I never really learned how to solder. Not well, at least. Sure, I can solder a PL259 onto the end of some coax and it works OK, but the connector usually hides the sloppiness of my handiwork. Don’t get me wrong, I’m not scared of a soldering iron — I just am not as practiced with it as some of the QRP kit builders that frequent this blog.
I searched online for an interesting kit to build and stumbled upon Elenco’s AmeriKit AK-100 Learn to Solder Kit (about $15). What better opportunity to
teach myself teach my son how to solder!
The kit includes a 25-watt soldering iron (Elenco SR-1N), a pair of diagonal cutters (Elenco ST-1), a spool of lead-free solder, and a solder practice kit containing a printed circuit board and various components. Also included is a nice 15-page guide to soldering and very detailed instructions about how to assemble the practice project. (I’ve yet to be disappointed in anything from Elenco. If you have kids or grandkids and they don’t have Elenco’s Snap Circuits Jr. Kit, it’s the best $20 gift you can buy them!)
This kit was a huge hit with my son. He had a great time placing each component in its clearly labeled place. After doing a few of the practice exercises, I was amazed at how proficient he became! I learned so many tips from the instruction manual about how to create good solder joints and electrical connections. The manual itself is well worth the price — the soldering iron and practice kit are a great bonus!
The included soldering instruction booklet covers general electronics basics like determining resistor and capacitor values, paying attention to polarity, and safety precautions. It also covers specific soldering (and desoldering) techniques for different types of work. There is an in-depth look at the different types of solder (when you would or wouldn’t use them) and many tips and tricks to making your job look more professional. You’ll have to excuse our solder joints in the pictures, however — there was a lot of learning and practicing going on! 🙂
After about an hour and a half, the project was done! We had a working siren with flashing red LEDs. My son couldn’t have been more proud of his work! Although we have done quite a few “tech” projects together, this was the first time we’d really gotten into circuit fabrication. It was time very well spent and I’m very excited to be creating a solid foundation of good habits. It’s always better to learn the right way instead of trying to erase bad habits later!
If you have a son or daughter (or grandchild!) interested in electronics, don’t hesitate to check out Elenco’s Learn To Solder Kit. Like Elenco’s other educational kits, it was well worth its modest price.
It took me a number of years to realize that correct soldering required two things:
1) The proper amount of heat from the soldering iron.
2) Solder that was thin enough to flow easily.
Needless to say, thick solder and a 25 watt iron are not very compatible.
I have used .032″ diameter 60/40 solder for years now. I use three different irons: 25 watts for delicate work, 35 watts for most circuits and 100 watts for PL-259’s and other heavy duty jobs.
Very true, Bill!
I hope others will leave their soldering pearls of wisdom here in the comments.
Couple of thoughts on soldering
1 Heat from the solder iron is conducted best when liquid solders is on the tip. So a little touch of solder on the tip makes it easier to heat the parts your putting together
2 solder will flow to the hots area so move the solder to the other side of the wire when it is hot enough to melt the solder it will flow all around the joint.
3 over heating solder boards components etc will cause lots of problems bigger is not good on soldering.
4 check your work with a magnifying glass if possible correct problems clean up the joint it will pay dividends down the road. finding a poor joint or short on a completed board is not fun
Good on ya’ for taking the time and interest to work with your son learning this delicate skill. For old timers like me, most of the basics are lost to time. But they are so ingrained as to make them second nature.
My father was used to working with solder when it came to copper tubing, so most of what I know, I learned while working myself up in the industry. I am greatful to him for helping me during my formative years. I miss him.
My profession is as a technician in the field of avionics. Because of the requirements determined by the FAA, and due to the “mission critical” imperitives, high reliability is paramount. See http://en.wikipedia.org/wiki/IPC_(electronics) for more info. Rather boring reading!
I recently (last fall) was recertified for IPC class 3 rework. Here’s what the requirements are for though-hole components. 360 degree coverage of solder on the solder side. 75% fill of the through hole barrel. 270 degree fill in the though hole barrel.
Kind of difficult to describe, but easy to visualise when you look at it.
Basically, make sure the solder lands on the side of the PCB away from the component is covered 360 degrees. The thru-hole barrel (assuming the PCB has thru-hole barrel as in a 2 sided board) should be filled 75%, and 270 degree coverage on the component side.
After almost 40 years of kit building, and almost that long professionally, that is how I’ve always done it.
Single sided boards, as I assume you are working with, just make sure the solder land is covered, and there is good wicking on the componet lead. More than 180 degree coverage, but 360 degree coverage is best. Look for a nice, smooth filet, not a blob of solder. It should look “pretty”!
Heat the joint of the component and the copper pad, while the soldering iron tip is in contact with with the pad on the PCB opposite the component side. Use “Transfer heating”, which is just melting a small amount of solder on the tip of the iron, and using that to increase the size of the contact area of the iron tip. Feed the solder wire to the component lead opposite the iron tip. Allow the solder to melt and flow into the connection. If you have access to solder flux, use it liberally!
After all these years soldering professionally, I don’t know 75 watts from 25 watt rating for soldering irons. I watch the iron tip temperatue. 650 degrees is plenty, unless you are working with a large ground plane. That requires patience.
My recommendations are that at some point, if you really want to get into it, is to spend a few extra bucks on a temperature controlled iron. Hakko makes a nice temp controlled iron for under a hundred bux.
I don’t like lead-free solder. The connection is brittle. I use 65%, 35% lead-tin mix, and the solder wire diameter is determined by what you are working with. Mostly, I use solder diameter of .015 inch (I get it free from work when it reaches expiration date (annually? Never figured that one out!). Don’t worry abut lead vapor, as you have to heat it much more than a soldering iron to vaporize it, when it becomes a problem. Just make sure you wash your hands after handling lead solder!
Wow, that was wordy! But as complex as it may seem, once you get the hang of it, you can do it without thinking about it.
Hope that helps, and if you need clarification, please drop me a line using my QRZ email address.
Good luck, and HAVE FUN! Melt some solder!
Thanks for the pointer, Karl. I’ve got a 12 year old son I want to teach whilst learning at the same time; this could be just the thing!
One of my relatives is practicing soldering at home. Whenever we pay a visit to their home my kids gather around his soldering stuff and always pointing me to buy them that kit but these kits are not safe to use for kids. They are curious to learn to solder. I think I should bring them this one. Thanks for sharing here the useful information!