Someone recently left a comment on one of my older blog-posts asking if I could go into a little more detail about my construction techniques. It’s a question I’ve been asked a few times and although I have never detailed them in one post, if you were to read the posts for my main construction projects, you’d probably be able to glean enough info and links to pick up what you need. However, that information is scattered around this blog, so this post is an attempt to gather all the tidbits into one place. Please note that this is not a step-by-step “how-to” instructional, but more a collection of thoughts, tips, and links. It is a rough guide to how I do it, and not intended to be definitive. There are many ways to achieve a goal, and your mission is to find the way that works best for you.
I get my PCB material from seller abcfab on eBay. He has a good selection of different thicknesses of substrate, double-sided and single-sided, and even different thicknesses of copper. 0.06″ thickness is a nice stout board, good for enclosures, and also for Manhattan construction. The lesser thicknesses would probably only work for small enclosures, but would be fine for most circuit construction, unless you’re using a larger board and specifically need something inflexible (a thicker board would probably be more stable for a regen, for example). Up until now, I have used 0.06″ board for both enclosures and circuits, but a friend recently gave me some really nice pieces of thinner board (about 0.04″, I think), which I will use for building circuits on. When buying from abcfab, my standard order is for 0.06″ thickness, 1oz/ft² weight copper, single-sided, FR-4 substrate material. FR-4 is a composite of woven fiberglass cloth with an epoxy resin binder that is flame resistant (hence the FR designation). He also has a few different colors, which are fun for enclosures. I have bought red, blue, and the usual light brownish-colored boards from him. I did try to find a supplier for small quantities of other colors, such as orange, but the only way I found to do it was to buy whole sheets from a supplier and have them cut down to size, either for my own stash, or perhaps to also distribute to other home-brewers to spread the cost out a bit.
I won’t go into detail on enclosure building here, but I talk about my methods in this post. Ken WA4MNT has an excellent tutorial here. I learned most of what I know about building PCB enclosures from Ken’s tutorial. Ken uses shears to cut his material. I found that scoring it deeply on both sides with a box cutter allows it to be flexed and snapped cleanly. Running a file over the edge gives a nice result.
Anyway, a little about building circuits, which is the main subject of this post. Here are my main tools –
At the top is a 2.25mm crochet hook, used for winding toroids. I use the hook to pull the wire through the toroid, which is a great way of keeping the turns snug against the core. Beneath it, from left to right, is a tube of superglue gel. The gel form works best – the liquid is just too runny and gets everywhere. Next is a pair of round-nose pliers with round cross-section jaws (Pro’s Kit 1PK-29). I use these for bending component leads for the rounded look –
Next to the rounded pliers is a pair of green-handled Xcelite MS543J flush cutters with ESD-safe cushion grip handles, and a couple of small jewelers screwdrivers (from a cheap set bought from Radio Shack), which I use for scraping lacquer off the board in the places where Manhattan pads will be glued, as well as pressing down on the pads when gluing them to the board. Then a pair of Pro’s Kit 1PK-036S long nose pliers. I didn’t like the spring action, so I removed the spring from the handle. Next is a red-handled pair of needle nose pliers (cheap ones from Radio Shack). On the far right is a craft knife or as some call it, a box cutter. In the UK we call them Stanley knives, after the brand – in the same way that the British also call a vacuum cleaner a Hoover, and we in the US talk about Scotch tape, while the Brits refer to the same thing as Sellotape. This craft knife is used to deeply score both sides of a piece of PCB material before breaking it cleanly off. You’ll go through blades fast with this method. I bought a pack of 100 blades as typically, I find that every time I score a board enough times on both sides so that it can be broken off, I need to replace the blade. Blades are cheap when bought in bulk, and it’s not worth putting up with substandard cuts just in order to save a few pennies.
Looking at the needle nose pliers a bit closer, you’ll see that I filed flats into the ends. This has nothing to do with Manhattan construction. I needed a specialty tool to remove the nut holding a VFO encoder pot on a Yaesu FT-817, and found out that after filing a couple of flats in the jaws of these pliers, they fit the cutouts in the pot nut perfectly, allowing me to use the pliers to unscrew the nut –
I forgot to photograph my steel rules. I have 3 of them – a 12″ one marked in mm, a 6″ one also marked in mm, and an 18″ one marked in inches. They are used for scoring the lines in boards when cutting the PCB material and, of course, for all other kinds of measuring applications.
Moving along, at the top of the next picture is a T-handled reamer. This is used for making larger holes in chassis and enclosures. I start out with a drilled smaller hole, and enlarge it with the reaming tool. The brand name is General, and it is a No. 130. Then from left to right are a couple of files – a mill bastard, and a half-round bastard. The hand drill (and set of bits at the far right) is much used for drilling holes in enclosures. Finally, in the middle is a set of small files, which are very useful for finishing off all kinds of holes and rough edges. This particular one is made by General #707476 and is called a 6-piece Swiss Needle File Set –
When gluing Manhattan pads down, I first scrape the lacquer away from the board with a small jewelers screwdriver in the area where the pad will be glued. I know you’re not supposed to use screwdrivers for scraping things, but these were from a cheap set. I also roughen up the underside of the MeSQUARE or MePAD with a sharp craft knife blade to help adhesion. I put a small drop of superglue gel in the center of the area on the board where the pad will be, and lower the pad into position with the long nose pliers.
This next part is tricky. Once you begin to push down on the pad, you only have a few seconds before it is glued fast to the board. The trouble is, that as you push down on it (with a screwdriver or whatever other implement you’re using), the pad tends to slip around on the gooey gel, and change position. If you’re fast, you will have time to re-position it as it does this. You achieve this with a combination of pushing down slowly, and quickly re-positioning it by nudging it with the screwdriver. Once you start pushing down, the clock is ticking. You’ll have time to re-position the pad if necessary, but you’ll have to be fast! The good news is that if you do succeed in gluing the pad down in the wrong place, you can remove it and try again. Just wait a couple of minutes for the glue to set, then slide a sharp craft blade under the pad and pop it off the board. Be careful when doing this so that you don’t slice a finger, or slip and damage something else on the board. Once the pad is off, you can scrape away any remaining glue and go for a second try.
Component leads can be pre-cut and pre-formed with the cutters and pliers, and then placed against the pads and board to check the fit, before soldering. A few folk have asked how to actually get the parts standing up on the pads in exactly the position desired. This is the wonder of tack-soldering. Most modern components come with the leads already pre-tinned. For the purposes of tack-soldering though, it helps to have just a bit more solder on them. Once you have tinned the lead(s), you can place the part in the position you want it using a pair of pliers (or other tool), and temporarily fasten it in place with a bit of heat from your soldering iron. Then you can either tack-solder or permanently solder the other lead into place, after which you go back to the first lead and make that solder job permanent. As well as using pliers, I often use jewelers screwdrivers to coax leads into the right positions – use whatever you have, and whatever works for you. You’ll develop your own techniques over time. It can be a slow process, often taking many years, so don’t despair – enjoy the journey!
Oh, I forgot to mention the soldering iron. A temperature-controlled soldering station is preferred over a cheaper iron without temperature control. A temperature-controlled iron can deliver more heat when needed, such as when soldering to a circuit board ground plane. It’s surprising how much heat even a small ground plane on a circuit board can “sink” away from the tip of a soldering iron. The station I use is a Hakko 936. I don’t believe they make that model any longer, but there are plenty of affordable soldering stations available, for around the $100 mark. As for tips, chisel tips are good for most purposes. I use a 1/16″ chisel tip for most things, switching to a smaller 1/32″ chisel tip for the more fiddly tasks. The flat sides of a chisel tip will allow you to transfer heat more effectively to the area being soldered than will a conical tip.
Oh, and test gear. The most important piece of test gear by far, is a multimeter. I have a 20 year-old analog multimeter from Radio Shack, which used to be my main meter. Nowadays, I mainly use it for the times when I’m peaking circuits, when being able to see a needle move on a scale makes it easier to adjust a control for a peak or a null. My main meter now is a cheap manual DMM, an Extech MN35. It was a gift from my friend Antoinette last Christmas. IIRC, they are about $25 –
Most folk seem to prefer auto-ranging DMM’s. My preference is for a manual, as I like the manual control. Whether you are using a manual or an auto-ranging DMM, you should have an idea of roughly what kind of voltage you expect to find at a particular point before poking the test prods anywhere near it. Knowing what voltage (or current, or resistance) ball-park you are in, it is no trouble, in my opinion, to switch the meter to the appropriate range. That may be just be my justification for the fact that I’m rather stuck in my ways, and just happen to prefer manual meters. It’s convenient that they are cheaper too 🙂 With a DMM like this as your sole piece of test gear, you can build an awful lot of stuff. There are cheaper DMM’s out there, but the really cheap ones have low build quality and poor accuracy, in my experience. I do also have an old Tek 465 oscilloscope which a local ham very generously gave me. Combined with a signal generator, you can do all sorts of fun things with a ‘scope, such as injecting a signal into an amp stage, and seeing what it looks like when it comes out (as well as calculating the gain of the stage). I recently used it to measure the output of a 5mW QRPp transmitter, by measuring the peak to peak voltage across a 50 ohm resistor. At such low output powers, RF probes aren’t accurate, and a ‘scope is a good way to go.
My DMM doesn’t measure capacitance, so this capacitance meter does a great job. I often check values of components before installing them into a circuit, as a double-check to ensure I didn’t misread the value printed on the part. I got this one for a little under $15 from Sparkfun. It measures capacitances from just a few pF up to many uF’s –
There are some really useful cheap pieces of test gear on eBay. I plan to ask for a little frequency counter, and maybe also an ESR meter for Christmas.
Anyway, the purpose of this post was to show you the tools I use for my home-brewing activities and hopefully, to demonstrate that you don’t need a lot of expensive ones to build a lot of cool things. However, if you have the interest and can afford it, feel free to get yourself lots of cool test gear!
Those are the basics, I think. I cannot think of any more right now. If you have any questions, feel free to ask them in the comments section and I’ll do my best to answer.