Giant temples of metal or hideous blots on the landscape? Phil Parker shares useful etched metalwork techniques with a Severn Models electricity pylon kit.
Pylons are one of the most recognisable symbols of the UK's electricity network. Throughout the countryside, they are either seen as a blot on the landscape or a vital feature of the modern world depending on your viewpoint.
Model pylons aren't common. Perhaps we like to imagine our miniature worlds without ugly structures? I suspect it's mainly because of the difficulty of taking a complex structure and rendering it to scale. These are very clean and precise designs that demand clean and precise model making and they are difficult to build.
It doesn't help that pylons are tall – anywhere between 50 and 180ft for most, unless you want to model the 580ft tall monster at Thurrock. While ready-to-use versions have been available from Hornby, among others, the spindly designs don't lend themselves well to injection-moulded plastic. Metal is a better option.
Unless you are keen enough to scratchbuild, it's time to find a pylon kit and here the selection is limited. I'm building one from Severn Models in etched brass for N gauge layouts. I have asked about a 4mm version, but the price would be high because of the large sheets of metal required. The designer, Andy Vaughan, just laughs when O gauge is suggested...
The kit is simple to build if you understand the correct ways to bend the pieces up from flat, so that's what I've concentrated on here. Each section of the tower is etched in two halves, which are brought together to form the 3D model. As long as your bends are crisp, and parts don't get mangled before assembly, you can't go wrong.
If you haven't worked with etched metal before, it's no different to assembling a card kit. Bends are marked with lines etched on the surface, and those lines should be on the
inside of the bend. As well as showing you where it is and making the bend easier to form, they keep it in the right place so you don't twist the surrounding metal.
The kit is designed for assembly with superglue, but I prefer to solder. As well as being faster, the joint is slightly stronger. That said, the pylons I've handled on the Severn Models exhibition stand didn't feel any weaker than my version, so perhaps I'm just old-fashioned!
Construction time was a fairly relaxed few hours, plus a few minutes for spray painting using a can of car primer aerosol. How many you require is up to you, but the average distance between pylons in the UK is 1200ft, so most of us won't need to fill our layouts with these metal monsters.
Parts are supplied on a pair of identical etched sheets. Each piece will need to be removed carefully by cutting through retaining tabs holding it in place. A large, sharp knife on a rubber cutting mat are my tools of choice for this job. The tabs are half etched to make them easier to cut and you can get the blade close to the piece you want to remove. Leave parts on the fret until you need them.
Engineers will prefer a robust set of bending bars. Fitted into a large vice, these clamp the metal along the bend line. The part being bent still needs to be supported, but you can be confident of a straight bend. Prices and designs vary, so search tool vendors for one that suits you.
All Severn Models kits are designed to be assembled using glue, but for etched brass, I prefer solder, partly as it's a lot quicker. With such spindly parts, one issue is that vigorously cleaning flux off the metal in the sink might cause damage, so I'm using non-corrosive liquid flux designed for electrical work. You need to be quicker with it than paste fluxes because the liquid evaporates fast, but with a bit of practice, this isn't a problem.
To remove each tiny leftover bit of tab, file along the edge of the part. Try to avoid working across the metal as this increases the chance of bending it – although a little finger pressure will usually unbend it again if required.
For the occasional kit builder, a pair of cheap steel rules will be perfectly adequate for the bends required in this model. They should be clamped in a vice, and care taken to ensure the top edges are aligned, but this method served me well for many locomotive kits over several years. The limitation is that the ends of the rule beyond the edge of the vice won't be clamped properly but for kits with a half-etched guide line, this isn't a big issue.
Each joint is smoothed with a fine abrasive stick, then polished with a fibreglass pencil. The trick to making neat joints is to use the minimum amount of solder, letting the flux and heat make it run where it's wanted. Most beginners put too much solder on, leading to more involved cleaning up. As long as the metal is clean, hot solder will flow.
All the fine pieces have to be bent to form the pylon shape and there are many ways to do this. The top-ofthe-line solution is a 'hold and fold' device. The metal is clamped under the aluminium former. Support the whole length of the piece with a rule, so it doesn't twist, and the bend is simple to make. The 'hold and fold' can be reversed, so the tongues are in the forming area, helping with smaller pieces. The device is an investment, but you should only ever need to buy one.
Smaller bends can easily be handled with pliers. I prefer square-ended versions with flat jaws but other shapes have their uses. They cost me £1 when I brought them years ago and I've not worn them out yet. Model-making equipment doesn't have to be expensive.
The biggest challenge in the build is laminating the three layers of brass making up the insulators. It's an area where using glue is easier. However, I simply tinned both sides of the middle layer, cover them with flux and pushed the facing layers on with a hot iron. This worked because they are small and allowing all the metal to be brought up to temperature so the solder runs.