Revival and Upgrade of a Vintage Weller Soldering Station

Did I already mention that I like to repair, resurrect, reuse, and re-purpose things? Yes?

This time I will tell you about the Weller Magnastat soldering irons and stations, and my love affair with my own, faithful Weller that lasts, by the way, almost 50 years now. So this must be true love.

The pictures above show the same station before and after...

Some days ago, a relative of mine mentioned that he is interested in tinkering with electronics. Since he is the very first in the family to show this strange kind of interest – apart from a long-gone grandfather and myself – I think it’s my obligation (and my pleasure) to support him as well as I can.

So, what’s the first item you need when you want to enter the realm of electronics? Right: a soldering iron.

All my former employers used Weller soldering equipment in R&D, manufacturing and workshops, and I very much liked the ergonomic design, the easy handling due to the highly flexibe cables, the reliability and the overall quality. So it was only natural for me to purchase a Weller iron, too, as soon as I could afford it. I was somewhat younger then. Needless to say, quality had its price even then. I couldn’t afford a complete soldering station, but rather had to make do with a Weller TCP soldering iron only. I connected it to a 24V transformer that I conveniently already had.

Whenever I was forced to use different makes of soldering irons, I remorsefully came back to my good old Weller as fast as I could, so this really must be love!

Without question, I would prefer that my relative also uses a Weller soldering iron – but that still is a hefty expense for a rookie…

Several years ago my former employer relocated manufacturing – from Switzerland first to the UK, and shortly after that to China. During this time a lot of tools, components, test and measuring gear, you name it, were literally thrown away at the Swiss HQ. I couldn’t stand letting some of these go. Among other things, I rescued several vintage Weller Magnastat soldering stations. They had been heavily used and needed quite a bit of cleaning, spare parts, a lot of elbow grease, and, most of all, some TLC. I even upgraded them with the solution mentioned in the last two steps of this instructable.

I had no use for them at the time, so I donated them to my friendly neigbourhood fab lab – which means there is nothing in stock for my relative. As they are expensive when purchased off the shelf, they are hardly affordable for a beginner.

But there is, of course, a different way: In an online auction, I managed to snag one for little money. No wonder, it was manufactured in 1976 (!), it showed signs of heavy use, and needed quite a bit of care.

Some impressions of the condition the station was in are given in the pictures above.

The easiest way to clean any electrical or electronic device is by taking it apart. Completely. Which I did.

When doing so, I heartily recommend that you document (take notes, sketches, pictures) each step, in order to facilitate reassembly. It’s amazing how much you can forget if a project has to be put aside for a day or two – or, as in my case, for a few minutes ;-)

An additional tip: Normally, a device uses different sizes of screws or other mounting hardware. Use several clean, stackable, paper or plastic cups (e.g. from your favourite yoghurt brand and flavour), and put the first set of screws into one of them. For the next disassembly step, place the next cup into the first (that already contains some screws) and put the next set of screws into the second cup, and so on. Upon reassembly you can then work your way through the stack of cups from top to bottom, i.e. in reverse order. This way it’s easy to find the correct screws for every single step.

Tools

What is required depends on the actual device you want to disassemble. For older devices, standard screwdrivers (flat blade, Phillips/Pozidriv, Allen) should do the trick. More recent units may require a set of special screwdrivers (or bits) for the abominable, but widely-used, tamper-proof screws. Together with some flat-nosed pliers, tweezers, and perhaps a monkey wrench you can go a long way.

Cleaning

Depending on the part concerned, you can use either warm/hot water together with some soap or dish detergent and a stiff-bristled brush, or methylated spirit and paper towels, or, if necessary, even the heavy equipment such as wire brushes, sandpaper, Scotch Brite or files. A glass-fibre eraser can be very helpful as well – but make sure to protect your hands and lungs from the tiny fibre fragments that fly around when using it. And when using a wire brush on smaller parts, protect your skin by putting on heavy-duty work gloves in order to avoid bloodshed.

After soaking/brushing under water, PLEASE ALLOW EVERYTHING TO DRY COMPLETELY – either over night or, even better, with the help of compressed air or a hair dryer.

Remember that water and all things electrical don’t go together well (and perhaps only once, and then never again). Make sure to NEVER submerge electronical components, switches, transformers, cables etc. in water!

At the beginning of this instructable there are pictures from before and after the cleaning process. The soldering station itself contains only a handful of electrical components anyway (the picture above gives you a partial view of its innards):

• A mains cable (already removed in the picture above)
• A screw terminal for connecting the mains cable internally
• A screw-on strain relief clamp for the mains cable (also not shown here – but you can see the threads where it is screwed on)
• An illuminated mains switch (you see the rear of it in the picture)
• A fuse holder with a 5x20 mm, 0.315 A slow-blow fuse (not visible here because it hides behind the switch)
• The 220/24 V mains transformer (yes, it's 220 V primary – the station was manufactured before the mains voltage harmonization - but this is no problem in this application)
• Two terminal posts for connecting the soldering iron (also mostly hidden)

Two parts from the top of the case (the narrow, heat-proof aluminium bracket for protecting the plastic case and the sponge for cleaning the soldering tip) were AWOL, but I had 2nd-hand replacements available in my junk box anyway, together with a ‘new’, re-used mains cable.

No leftover screws after reassembly!

It’s alive!

Ok, almost :-(. I discovered that the mains switch had a contact problem – no wonder, after 46 years of faithful service. Unfortunately I couldn’t find a replacement fitting exactly into the front panel cut-out.

But the Marquardt switches used back then can, unlike their modern counterparts, be disassembled, their contacts cleaned and readjusted, and (with the help of tweezers, a bit of luck, several drops of perspiration and a few words that must not be reproduced in print) be reassembled and reused, just as a makeshift solution until a replacement arrives.

I thought it, then, a good idea to insulate the bare Faston connectors plugged to the mains switch (see picture) and the solder lugs of the fuse holder by a few pieces of heat-shrink tube for improved electrical safety.

Update 2022-06-13

I asked at the Marquardt HQ in Germany whether they might have one of these switches lying around in their museum, archive, or whatever. And, surprise! I indeed received one in the mail last saturday - free of charge!

I'm very much impressed, since this kind of customer relationship management is extremely unusual these days. Thank you, Marquardt!

Now let’s get to the tricky part – PLEASE DON'T start disassembling your Magnastat before having thoroughly read the following paragraph.

A Magnastat iron consists of (from top to bottom):

• The Weller-typical, turquoise-coloured handle made from ABS
• A highly flexible cable with heat-proof silicone rubber insulation (not shown here)
• A plastic sleeve and set screw for fixing the cable at the end of the handle (some sort of strain relief)
• A connecting piece, made from phenolic paper and some riveted solder lugs – for connecting the cable, the Magnastat switch assembly and the heater element
• A spiral spring – for separating the Magnastat switch assembly from the connection piece
• The Magnastat switch assembly
• The heater element, attached to the handle with 3 screws
• A stainless steel screw-on sleeve – for fixing the soldering tip
• The soldering tip

More details and a description of the functional principle will follow later.

/!\ You need to be VERY careful when disassembling your iron because the two wires going to the heater element are thin, brittle, and don’t suffer tensile stress gladly (I had to learn that the hard way earlier).

Unscrew the plastic set screw first, and then unscrew the heating element (3 screws). Now you can slide everything out towards the front by pushing the cable in from the rear end of the handle (DO NOT pull from the front!).

The early Magnastat irons came without a connector. They were connected to the station with two screw terminals. Newer ones are equipped with a DIN connector. In order to remove the handle for cleaning, the cable has to be unsoldered either on the connector end or on the other end, where it is soldered to the internal connecting piece mentioned above. Be aware: to do so, you have to solder within a soldering iron – which, obviously, calls for a second soldering iron!

The handle and the cable can then be cleaned with some methylated spirit, paper towels, a bit of patience and some elbow grease. Do NOT use more aggressive cleaning fluids such as benzine, thinner, acetone etc., since they might either make the plastic brittle or dissolve it.

Please leave the Magnastat switch assembly, the heater element and the other innards as they are!

The screw-on sleeve (2nd from the bottom in the picture above) is most probably dark or even black from heavy use, perhaps a bit dented, too. You might leave that as it is since it will become dark again soon when using the iron. If you want to clean it anyway, I suggest you take your cordless drill, insert an 8mm drill bit and slide the sleeve (with the hex nut first) over the drill bit. Take a piece of sand paper (or perhaps some Scotch Brite), wrap it around the sleeve by about one half turn, and slowly! start the drill. Only use light pressure with the sand paper so that the drill bit drives the sleeve without slipping or – beware! – drilling through its front end. When you feel the sand paper getting hot, your drill is too fast and/or your pressure is too strong. If the sleeve isn’t dented too much, you can get it nice and shiny this way without major effort.

You might now re-assemble your soldering iron and use it as it is, and you should present it in any case with one or more new soldering tips. I recommend buying the Plato brand rather than original Weller tips – they are slightly less expensive, and they solder, in my opinion, somewhat better than the originals.

However, I strongly recommend an upgrade that will help your Magnastat outliving you. It’s easy to do, in particular while your iron is already disassembled – see the next two steps.

Without going too deep into the details (they follow in the next step), there is one component in a Weller Magnastat soldering iron that can, after many years of use, fail: The contacts of the Magnastat switch that regulates the temperature of the soldering tip. It is located inside the iron and can seize up, resulting in an overheated tip and, with a little time and bad luck, in a burnt-out heating element; replacement heater elements are still available but expensive.

In 2014, my then favourite electronics magazine (Elektor) published an upgrade to the Weller Magnastat irons meant to solve this problem. In this article, also the functional principle of the Magnastat temperature-regulated soldering irons is described thoroughly and well, there’s no reason to repeat it here.

But alas, after having implemented this rather simple solution, I found out that it didn't work at all!

To upgrade your Magnastat iron, you will need:

• A triac (e.g. BT138)
• A 1kΩ / ¼W resistor
• Some flexible, stranded wire (cross-section not less than 0.5mm²)
• A bit of heat shrink tube.

The information on this upgrade is attached here. However, if you want to make it work, you need to observe my own two cents as well. They are also contained in the PDF document.

And BE WARNED again! When performing this upgrade you have to solder within a soldering iron which, obviously, calls for a second soldering iron – a vicious circle! I suggest that you borrow one to do so. If you plan to replace your old, junky iron by a refurbished Weller, you could allow the former its last mission...