Choosing the Right Soldering Iron for Electronics Work

Kemudian, one of my Facebook or myspace buddies, wrote to me personally asking about choosing a soldering iron:

“Quick question… I’m buying new soldering iron. would you recommend anything under 40 us dollars without a soldering train station? I’m getting sick and tired of my RadioShack 45 watt flat iron with the screw on tips (and needing to use a bench grinder every day to clean the tips). ” the link

I’ve been asked this question quite a bit, so I assumed it to be time to put something jointly explaining about soldering iron, flux and tinning. 

Soldering Iron
The first thing I would recommend achievement an adjustable temperature soldering iron, and get used to setting the proper temperatures for different types of parts you will work with – hotter for greater gauge, and cooler for thinner, finer work. We typically work in the 325F to 400F range. I’ve been using the Velleman LAB1U, it has a built in multi-meter and power supply. These types of can be a lttle bit high priced, so look at Weller brand – sometimes they go on sale for around $40. I would avoid the Cold Heat soldering irons – they are really faulty for delicate electronics, as are the big soldering “gun” type irons.

I actually used to use quite large gauge solder and tips, but just just lately (after doing a whole lot of surface-mount work) changed to 1/32? tip and 0. 32? diameter solder. This allows for much finer control with less overspill.

My soldering straightener has a built in “damp sponge” to completely clean off excess solder between uses. In the past I actually have used regular newspaper towels to do the same job, but a dedicated sponge with a circular hole cut in the middle really works best.

Helping Hands
The next thing I didn’t be without is are some “Helping Hands” – these are pairs of crocodile clips that can be used to maintain the workpiece while you concentrate on the soldering. this is very important, as it won’t be well before you realise that you need 4 hands to solder things.

A lot better than helping hands is a:

Bench Vice/Vise
I purchased one of these 2 years ago and it is proven to be invaluable. The brand I prefer is “PanaVise” and they have a range of bases and options – Fry’s carries them, and they are available online. You can position the complete PCB you will work on into the vice, put the components and then just flip it over to solder.

Flux Pencil
Rosin Flux is a substance that encourages the solder to flow. In the event you find that you are having difficulty getting a good solder joint then it’s probably because the heat transfer isn’t working correctly, or the components are dirty. Applying some solder flux to the joint area will really help – I’ve recently been by using a flux pen for years and wouldn’t wish to be without one. An alternate is flux paste – like toothpaste it comes in a tube and can be applied with the fingers.

Tip Tinner and Cleaner
When you first fit a fresh soldering iron tip will probably be shiny, shiny and very hard to work with. The solder will never stick to it and so you are unable to “tin” the tip properly. Some people uses fine sandpaper to break in a new tip but I favor to drop the new tip into some RadioShack “Tip Tinner and Cleaner”. This begins the process nicely. Really also a good idea to dip the soldering iron after you are finished, and before you switch off. I find that it truly helps to prevent the tip from wearing out prematurely.

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If you do a lot of soldering, then you need to go installed on your bench to reflect the fumes far from your face. It’s not suggested to breath in solder fumes at all. We use a tiny fan, but a proper extractor is definitely a good idea.

Wire Blades
The last piece of essential equipment is some well-defined, flat bottomed wire blades. These are being used to cut off excess component line (the “leg”) after soldering. The flat bottom is important to find the cut as near the PCB as possible. Avoid go too cheap with these, I paid about $17 for mine.

That pretty much covers the principles of soldering, I would also think about acquiring a loupe (magnifier), some solder wick and solder “sucker” for removal, wire stripdance and isopropyl alcohol and an old toothbrush for flux removal.

Very soon I’ll come up with a series of articles on soldering technique – covering basic through-hole assembly, and the greater advanced surface-mount technology.

Dorrie Hobley was born in the UK, and progressed up in the Midlands watching Doctor Who*, Dark night Rider, Batman and lots of other trashy TV shows.

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