We asked our MAKEcation Camp Counselor, Dave Hrynkiw, to share with us some of the common mistakes he sees newbies making when learning to solder. He shares some of his thoughts below.
Dave is the geek behind the woman (hey Cheryl!) who runs the Solarbotics and HVW Technologies. He’s our virtual Camp Counselor during “Teach Your Family to Solder” week. If you have any questions for Dave related to soldering, send email to firstname.lastname@example.org.
Using Too Little Heat: This is an issue when you’re using those wimpy 10- or 15-watt pencil-type soldering irons. They’re usually purchased as part of a set which includes some murky solder, a useless soldering-iron “stand,” and a “what is this thing for?” mini-wrench, used for replacing the tip (trust me, the iron ain’t worth that effort). The idea behind soldering is to heat the item, and then melt the solder to the item. In most electronics situations, that item will likely be a wire, or an electronic component. When you have an iron that generates wimpy amounts of heat, trying to heat up the item will take longer than it should, which will usually lead to damaged components from excessive heating, or a messy solder job (because the builder got impatient and melted the solder to the tip and tried to “paint” the molten solder to the joint). Either situation is bad. Save those wimpy irons for burning your name into a piece of wood, or roasting marshmallows from the inside-out (but don’t eat them! – bet that iron isn’t lead-free/RoHS compliant).
Using Too Much Heat: We often see kits come in for repair that have been scorched like they’ve been soldered with a butane torch! Sometimes they have! Or with one of those huge pistol-grip soldering guns designed for soldering 12-gauge car trailer connections in mid-winter Alaska. A printed circuit board’s copper traces are barely more than glued onto the phenolic or fiberglass substrate we call a PCB. Too much heat kills this adhesive layer, making traces and pads lift from the board like a bad sunburn two days after that bender on the beach (sorry for that imagery, but it’s pretty accurate). Go easy with the firestick, chief. The boards and components are made to withstand a certain amount of heat in the soldering process, not the heat of a solar flare.
Painting: This is the most common newbie mistake. As mentioned under “Too Little Heat,” soldering is the process of heating the items you want to solder together, and melting the solder to those items, using the heat in the items (as transfered by your iron). It’s the reverse of painting. The (wrong) painting method is melting solder onto your iron, then trying to smear it onto the item you’re soldering. What you end up with is a solder job that will most likely flake right off. You want to paint? Try the Bob Ross-style class at the local community college (Jeez, I miss that guy — and his tremendous hair). Think of the soldering iron as a gravity gun for solder. Stick the iron where you want the solder to go, and when you apply it, the solder will naturally flow towards the heat. You can’t convince solder to go where there’s no heat. It’s kinda like a retired Canadian that way.
Appriopriate Tools, Equipment, and Supplies: I bet you think I’m going to suggest getting the best soldering iron you can afford, right? Nope. A decent low-cost iron is fine. If you stick with electronics long enough to thoroughly wear out a medium-quality 20-to-30 watt pencil-type soldering iron, then go ahead and buy something fancier. Spend about $25 on a iron (not a kit!) and you’ll be all set.
Solder comes in many types and flavors, the most common being “Lead-free” and “Lead/Tin.” Given a choice, I’ll take leaded any day. There’s a reason all military-grade electronics are still done with lead-based solder. It’s just better. It melts at lower temperatures, flows better, and ends up looking shiny when applied properly. The other stuff looks like crud, even when it’s done correctly, which is especially troublesome for beginners looking for proof of a healthy join. Yes, there are lead-based dangers, but use some common sense, good ventilation, and don’t eat while you’re working (solder/fingers, fingers/sandwich, sandwich/brain, brain/dumb), and wash your hands well with soap when you’re done.
Secondary to the leaded/non-lead solder issue, there’s the decision of “no-clean” vs. “rosin” flux. OK, there are more types, but those are the main types. Flux is a chemical paste that’s usually in the core of the solder you use. When you melt it, the flux cleans the surfaces and “lubricates” the soldering, making the metals bind correctly. If you have a choice, get a “no-clean” flux, as the other types will make your solder joints look like burned sugar.
In short, get a $25, 20-to-30 watt pencil-type soldering iron, a $12 1-lb. roll of no-clean lead/tin solder (that’s lots – share with family and friends), don’t floss with the solder, and don’t paint it onto your projects.
Bonus Tip: Get a container of Multicore “Tip Cleaner.” Best $3 you’ll spend on a soldering accessory. It will triple the life of your solder tips, and make almost any gungy tip look clean and shiny again. Just don’t breath the fumes when you push a hot dirty tip into this pumice-like substance.