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Essential Tools for Home Construction

by MattDawson, GW0VNR

Soldering Iron

Ask two amateurs which they prefer and you'll get eight different answers. Perhaps more. A soldering iron is the basic, fundamental tool of the art and they are available in many different types, all with strengths and weaknesses. Instead of recommending one over another, I'll discuss what to look for.

Power

Like amateur radio itself, you should stick to the least possible power to get the job done. For most work, a 15W iron will be sufficient and preferable to limit thermal damage to components and PCB material whilst still providing enough heat to flow a joint correctly.

There are times when you will need more, for example soldering to a large area of ground plane or the middle lead of a TO-220 package (those big transistors with a heat sink tab). For this, a 25W iron is sufficient with a larger tip to improve heat transfer.

Bits

A 2.3mm "hoof" bit is ideal for most work. You can solder an SOIC (small outline surface mount integrated circuit) or a 0.25W resistor with equal facility using this popular bit. Other bits' usefulness will become apparent with experience. For the 25W iron, a 4mm "hoof" bit is ideal.

Temperature controlled or not?

There is a lot to be said for temperature controlled soldering stations, not least of which is negating the need for multiple irons. They are usually more expensive, however, and consumables can be hard to find for some. Also, beware of cheap stations claiming to be temperature controlled. There is one such station on the market which has as its control circuitry the equivalent of a lighting dimmer which may cause issues for a beginner.

Expect a good TC unit to cost much more than a straight iron. However, for most work, a normal iron will suffice.

Solder

I won't beat around the bush here: 60/40 or 63/37 eutectic tin-lead rosin cored wire. Use nothing else. Lead-free solder has two drawbacks: It requires a higher temperature to flow correctly or you get “dry joints” and it grows tin whiskers which can be a monumental nuisance to find. Get solder in 0.7 and 1mm gauges.

Cable

Sounds like a minor detail but, believe me, when you're using an iron as much as you will be doing, the cable plays a major role. Try to get an iron with a silicone cable if at all possible. These are much more flexible than PVC and resist the inevitable accident a little better. You will have a full range of movement of the iron without having to mess about with its power cord.

Stand

Again, personal preference. I prefer the heavy based “coil” stands with integral sponge holder as they can be more or less ignored. They'll always stay where you put them and the iron is a loose fit in the coil so, with a bit of experience, you'll be able to pick up and put down the iron without even thinking about it. Other soldering technology

There are, of course, multiple ways of manipulating or populating a PCB these days. Hot air rework stations, desoldering stations, pots, solder paste and liquid flux will all become apparent in time. However, a beginner should stick with a soldering iron and the appropriate gauge of solder for the job in hand until such things become essential in the pursuit of the art.

What's hot

Antex, Weller, many of the far eastern soldering stations on eBay with a digital display and a good supply of spare, good quality bits.

attachment:Antex.jpg

Antex C-15 with 2.3mm "hoof" bit and silicone cord – well used!

The best option by far for a beginner is a temperature controlled station with a digital readout.

What's not

$3 irons, anything with the bit held in with a single screw.

Beware of stations claiming to be temperature controlled which aren't. The Maplin N78AR is an example of this. They can be fine in the hands of experienced constructors but may cause problems for beginners because the tip temperature is so hard to set correctly. They're actually variable power rather than temperature controlled, so any markings on the dial will be wildly misleading.

Also, triac controlled irons may put out a huge amount of RF noise on the mains similar to that found with cheap lighting dimmer switches. Tony, G4WIF wrote an article in SPRAT, the journal of the G-QRP club which is a highly recommended read, which discusses this. He has kindly made this article available on the club web site at:

Tony's article on the N78AR

Tips for use

Three important items: Cleanliness, cleanliness and cleanliness. Clean the iron's tip regularly on a brass wire tip cleaner, which is less likely to cause thermal shock to a tip than the traditional damp sponge method. If you must use a sponge, use it dry. Keep the joint clean. If the solder wire “balls” at the end, cut the ball off with snips. Apply the iron to the joint first, allow the joint to reach temperature and apply the solder to the joint. Never apply the solder to the iron, although “tinning the bit,” which is applying solder directly to the bit then wiping the solder away on the tip cleaner, is good practice.

A flux pen is a handy item to have. These are useful for re-making joints, priming fresh PCB pads and surface mount rework.

attachment:fluxpen.jpg

Flux pen – rather tatty from much use.

Desoldering

Get a decent desoldering pump (also known as a solder sucker) with a locking plunger and replaceable nozzle. The rubber bulb types are useless for this job but do have another use for blowing out plated through holes once the component has been removed.

When cleaning these out, it is usually a good idea to use just a little silicone based furniture polish. This does two things: It retains the seal between the O-ring and the cylinder and stops waste solder sticking to the plunger.

attachment:Pump.jpg

A typical desoldering pump.

Solder wick is most useful for removing excess solder from joints, removing old solder when repairing kit with dry joints and cleaning up solder shorts. It is, however, useless for desoldering through-hole components.

attachment:Soldamop.jpg

Solder wick

Cleaning

The most useful solvent you can have in your armoury is isopropyl alcohol (rubbing alcohol, isopropanol). This has a myriad of uses in the electronics lab for cleaning flux from PCBs, removing etch resist from boards after etching, as a contact cleaner and, when diluted 30% IPA / 70% H2O (distilled water), a general purpose residue-free cleaner.

Cutters

These are essential and it pays to get good quality items. The most common form are diagonal side cutters, which have blades at a slight angle to the handles. These come in two varieties: Flush cut and symmetrical. A beginner is better off using symmetrical cut for PCB work as there is less chance of damaging the PCB and joint than with flush cut. Flush cut side-cutters become useful with experience. Other types are oblique blade and end cutters.

attachment:OldCutters.jpg

Well used diagonal side cutters.

What's hot

Erem, Knipex, most good quality carbon steel cutters with proper box or lap joint fulcrums.

What's not

Anything made from pressed steel or has a rivet fulcrum which allows the blades to move laterally.

Tips for use

When using symmetrical cutters, ensure the cut is square to the lead, you only cut one lead at a time (most important) and you do not pull the joint away from the board. When using flush cut blades you must also ensure the cut does not damage the solder joint.

Never dig the ends of the blades into the joint. Also ensure that the ends of the blades do not damage surrounding tracks.

To strip PVC and other coated wires, use the correct wire stripping tool, such as the one below:

attachment:wirestrip.jpg

Wire stripping tool with multiple gauge blades.

attachment:stripdetail.jpg

Detail of multiple gauge blades.

Pliers

You should have a good selection of these. Needle nosed, round, flat nosed etc. all come in handy when fitting components, bending component leads and other general work. A pair of forceps can also be useful, especially the locking type “artery” forceps.

attachment:forceps.jpg

Forceps.

What's hot

As for cutters, anything with a decent box or lap joint fulcrum.

What's not

Again, poor quality pressed steel and rivet fulcrums.

Tips for use

These are not spanners. If you need to loosen or tighten a nut or stand-off, use a nut spinner or the correct spanner. Pliers will ruin hexagonal nuts.

attachment:rnpliers.jpg

Lap jointed round nosed pliers.

Tweezers

Useful for surface mount components and when winding coils such as Toko 10K types. Always buy good quality stainless steel tweezers as these resist solder and flux.

What's hot

Stainless steel and anything with a PTFE coating. Good quality electronics tweezers with hardened, ground precision tips are hard to find.

What's not

Pretty much everything designed for pulling eyebrows, in sets or in first aid kits. The points should align perfectly and not pull apart when you bring the centre of the arms together completely. If they do, the arms are of poor quality and the tweezers will be utterly useless for electronics.

Tips for use

Keep the tips clean but ensure you don't remove any PTFE coating on good quality electronics tweezers. When using tweezers for surface mount components, try to keep the tips away from the solder and pads as they will sink away the heat you're trying to use to form or desolder the joint.

When soldering transistors, it can be worthwhile clamping the leads just above the board with locking forceps or self-closing tweezers to sink away the heat of soldering before it reaches the package itself. This may not be practical on some RF circuits where lead length must be kept to a minimum, although in this case attaching a small heatsink to the device's encapsulation while soldering can allow much of the heat to be dissipated before it destroys the device.

attachment:tweezersink.jpg

Transistor with self-closing tweezers as heatsink.

Trimming tools

Here's a misunderstood subject. Trimming or “tweaking” tools are varied and it's essential to use the correct tool for the part you're adjusting. The basics are a Spectrol type tool for multi-turn pots and trimmer capacitors, a Toko 10K tool which should be home-made (and I'll show you how to make one) and a ceramic bladed tool for conventional skeleton or Bourns type pots and trimmer capacitors.

DO NOT try to use jewellers' screwdrivers on pots, cores or anything else. Apart from the likelihood of damaging the part you're adjusting, they're also conductive and ferrous and will affect the adjustment of trimmer capacitors and cores.

If you are ever going to neutralise or tune up a tube/valve PA stage, you will also need a long-reach insulated trimming tool. Never use anything else near high voltages and keep one hand in your pocket at all times when working live with such equipment. Arm to arm DC shocks which track across the chest are the most often fatal type.

Never work on HT alone. Make sure your family or anyone else in the house knows what you are doing and understands to shut whatever you're working on down in an emergency before attending to you.

Sometimes the only way to fulfill a need: Make something!

Toko 10K coils and similar IF transformer type inductors are used in many amateur projects for tuned circuits, filters, inter-stage coupling and impedance transformation. The cores they use are fragile and very brittle, so you need a special tool to adjust them.

attachment:BPF11-web.jpg

11 band bandpass filter (before adding 60m) using Toko 10K inductors.

To make a Toko trimming tool, you'll need the body of an old plastic tool (which are useless for slotted cores so, in all probability, will already be missing its blade) and a small nylon cable/zip tie or an off-cut from one.

Take the very end of the tie and cut about 35mm/1.5” of the tapered end. At the very end af this tapered section, square it off with a craft knife to get a perfect rectangle profile. You should end up with something with a cross-section of about 2mm x.0.75mm that will be the blade of your tool.

Take your old plastic trimming tool, remove any leftover blade and, using a Dremel style rotary tool with a cutting disk, cut a slot of about 1”/25mm in depth into the end. This will hold the blade we made above.

Nylon doesn't glue very well but we'll use some general purpose adhesive to hold the blade steady instead of relying on friction. Leave to set.

Finally, tightly “whip” the length of the slot with thread (ordinary sewing cotton thread will do for this) and apply a coat of something like clear nail varnish to hold it in place. Leave to cure until hard.

attachment:TokoTool.jpg

The finished Toko tool.

What you end up with is a tool that fits the cores perfectly, has enough “give” to not break the fragile ferrite material but has enough control of the core to tune to perfection.

What's hot

Spectrol, MuRata, ceramic blades and our little Toko trimmer.

attachment:trimtools_good.jpg

Top to bottom: Long reach insulated; Spectrol type; MuRata trimmer capacitor ceramic; Combi blade/hex ceramic.

What's not

Plastic bladed tools for anything other than hexagonal cores. They're a waste of money and time.

attachment:PlasticTrim.jpg

Avoid these if possible.

Tips for use

Always ensure that the tool is a correct fit into whatever you're adjusting. Do not force the adjustment. In some ferrite cored formers, wax may have been used to stop vibration moving the core. If this is the case, the procedure is to bring a hot soldering iron into contact with the top of the core (NOT the former) for a few seconds before trying to move the core again. Repeat this procedure until the core moves freely with the correct tool. Remember, once it is broken, the whole former is useless.

I'm saying this again as it is the most important bit of information in this section: Never use a screwdriver.

Eyesight

We're not all blessed with 20/20 vision, especially in bad light. Most of us will need one or more aids for our tired eyes to do the job properly. The most useful piece of equipment is the illuminated inspection magnifier with an angle-poise stand:

attachment:InspectionMag.jpg

Illuminated inspection magnifier.

Not only does this illuminate your workspace with good, well-diffused light, it also allows you to focus on the particular area of your project you are working on while leaving your hands free to hold an iron and solder. This is probably the most useful piece of kit you can buy once you have your workbench hand tools acquired.

As pointed out by a "friend," these do have their drawbacks. Particularly, you need to keep the solder sucker away from this device, otherwise one day you'll end up happily peering through the magnifier at the joint you're trying to desolder, hitting the release and ending up with bits of T9 tube all over your bench as the plunger hits the lamp. I myself have done this twice in the space of as many months as said "friend" will gleefully confirm to anyone who will listen.

You may find you need some hand-held devices to read component markings and such. Another useful piece of kit is the illuminated hand magnifier.

attachment:HandMag.jpg

Illuminated handheld magnifier.

These are especially useful for peering inside equipment. Also consider getting a few loupes, which are handy for checking for bad joints, shorts and extremely small component markings.

attachment:Loupes.jpg

Eye loupes.

Multimeter

You will need one of these quite soon on your journey with home construction. Your first purchase should always be a decent analogue meter with high sensitivity (ohms per volt) rating. The reason I always recommend an analogue meter first is twofold: Firstly, you can see clearly any trend in the readings and secondly digital multimeters' readings may be affected by a combination of ripple (AC superimposed on a DC level) and sampling rate (the periods the multimeter's analogue to digital circuitry "captures" the level). If you're getting wacky readings on a digital meter, try your analogue before looking for faults.

attachment:analogue.jpg

Analogue multimeter with mirrored scale.

Ideally, your analogue meter should include a 500mA and 10A range. You will need these for basic tasks such as setting the bias on a PA circuit and checking current consumption.

A good auto-ranging digital multimeter (DVM) is invaluable. Try to get one with a continuity buzzer. The ability to test connections while keeping your eyes on the probes is priceless. Auto-ranging means the meter selects the display range according to the input and displays it in the best resolution the instrument is capable of.

attachment:autorange.jpg

Auto-ranging digital multimeter with fused probes.

A basic digital meter is also useful, especially those that include a transistor tester. The one below measures transistor current gain (beta β or hFE) for both NPN and PNP devices, has a diode forward voltage drop display and an LED tester, all useful to have.

attachment:basicdigital.jpg

Basic digital multimeter measuring the hFE of a 2N3904 transistor.

Other handy aids

The robotic looking thing below is a helping or third hand. These are invaluable when tackling jobs such as assembling connectors or tinning leads. They have a pair of articulated arms with croc clips at the ends for holding wire, pins, even small PCBs with a heavy cast-iron base. Get one. You won't regret it.

attachment:thirdhand.jpg

Third hand.

Also useful to have about are dental picks. These are stainless steel items that are useful for prodding and scraping, two things you'll be doing a lot of. Like the tweezers, stainless steel is a must to stop solder attaching itself to the tool when clearing solder shorts etc.

attachment:DentalPick.jpg

Dental pick.

An Xacto knife or other scalpel-like craft tool is handy to have. They're useful for clearing solder shorts, cutting tracks and sorting out etch process faults on PCBs.

A FET dip meter is a handy piece of test equipment to have. The one below is a commercial offering but these are ideal weekend projects to build. They can be used for checking trap resonance, antenna resonance, tuned circuits, unknown capacitor or inductor values, testing crystals, as a crude signal generator or as an absorption wavemeter.

attachment:dipmeter.jpg

FET dip meter.

Closing thoughts

By now you will realise that I have not mentioned screwdrivers at all. This is because the screwdriver has one use and one only: Driving screws. This is the most abused piece of equipment on the electronics hobbyist's bench. Choose a magnetic tipped set of ordinary screwdrivers and use them for screws and bolts only. If you're using a driver near anything else, you're committing a cardinal sin and no sympathy will be extended for the results by any experienced constructor.

Other tools will become necessary in time and, by that time, you will be experienced enough to know what will work and what won't. Always try to get good quality tools that will last a long time. Experienced constructors use tools to the point that they become familiar and almost extensions of their own bodies. If you're discarding and replacing tools all the time, you won't find this joy yourself. Find what works for you and stick with it.

Good luck with your projects and may you find as much joy in creation as we do!

Acknowledgements

With thanks (in call-sign alphabetical order) to Steve G0XAR, Stuart G3WDL, Tony G4WIF, Chris KQ2RP, Colin M5FRA and Soeren OZ2DAK for their input and constructive comments while preparing this document.

HamradioBuilderTools (last edited 2012-07-12 22:01:08 by DianeBruce)