DIY Spot Welder Doesn’t Look Like it Will Immediately Kill You

We love hacks that involve mains voltage, but most of the time, for safety’s sake, we secretly hope for that one macabre commenter that details every imaginable way the questionable design choices will result in death. This spot welder may still be dangerous, but it looks like they took some precautions to make it non-lethal, and that counts for a lot.

After their extremely questionable high speed belt sander, this one is, refreshingly, extremely well done. It starts of as a dead standard microwave spot welder build: take apart microwave, try not to die from large capacitor, remove coil, modify coil, and hook up.

After that, it gets to some nice heavy metal music fabrication. Aside from a slightly shocking number of fresh OSHA reportable hand injuries (wear gloves!) the build goes together well. A lot of planning obviously went into it, from the actively cooled transformer to what appears to be a resettable timer circuit for the weld duration, not to mention the way that it just fit together so well at the end. There were some neat ideas as far as home mechanics go that we’ll be using in some of our projects.

In the end, the proof is in the spot-weld. The timer is set, pedal gets pressed down, and when tested, the sheet metal breaks instead of the weld. Video after the break.

Continue reading “DIY Spot Welder Doesn’t Look Like it Will Immediately Kill You”

Arduino Nano Runs Battery Spot Welder

Soldering might look like a tempting and cheap alternative when building or repairing a battery pack, but the heat of the iron could damage the cell, and the resulting connection won’t be as good as a weld. Fortunately, though, a decent spot welder isn’t that tough to build, as [KaeptnBalu] shows us with his Arduino-controlled battery spot welder.

spot_welder_zoomWhen it comes to delivering the high currents necessary for spot welding, the Arduino Nano is not necessarily the first thing that comes to mind. But the need for a precisely controlled welding pulse makes the microcontroller a natural for this build, as long as the current handling is outsourced. In [KaeptnBalu]’s build, he lets an array of beefy MOSFETs on a separate PCB handle the welding current. The high-current wiring is particularly interesting – heavy gauge stranded wire is split in half, formed into a U, tinned, and each leg gets soldered to the MOSFET board. Welding tips are simply solid copper wire, and the whole thing is powered by a car battery, or maybe two if the job needs extra amps. The video below shows the high-quality welds the rig can produce.

Spot welders are a favorite on Hackaday, and we’ve seen both simple and complicated builds. This build hits the sweet spot of complexity and functionality, and having one on hand would open up a lot of battery-hacking possibilities.

Continue reading “Arduino Nano Runs Battery Spot Welder”

The Nicest Home Made Spot Welder We’ve Ever Seen

By golly, look at the build quality of this homemade spot welder.

Just about everyone on here knows it’s quite possible to build one of these things using a re-wrapped microwave transformer, but they’re usually made of wood like the one we swap on Friday, and we often wonder how much real use they get other than “hey look I built a spot welder!”. I myself made one, but then ended up buying a professional one because it works better. Not [Matthew Borgatti] though, his looks better and has more features than even the one I bought!


Why? Because he put some serious thought into his design. He even 3D modeled the whole thing in SolidWorks.

Beyond the excellent laser cut enclosure (complete with ratcheting work piece clamping), [Matt’s] also added an Arduino to create a timing circuit. Most times you just squeeze the clamp, press the button, and watch the metal heat up — “I think that’s good…”

But with an actual timing circuit you can calculate how much time you need versus current and electrode size to produce a good quality weld.

Continue reading “The Nicest Home Made Spot Welder We’ve Ever Seen”

Joining Sheet Metal Together with a DIY Spot Welder

Once in a while there comes a time that you need a tool for one specific job. In these cases, it doesn’t make much sense to buy an expensive tool to use just once or twice. For most of us, Spot Welders would fall into this category. [mrjohngoh] had the need to join two pieces of sheet metal. Instead of purchasing a commercial unit, he set out to make his own spot welder.

spotwelder A spot welder works by passing an electric current through two thin pieces of metal. The resistance of the metal work pieces and the current passed though them creates enough heat to melt and join the two together at a single spot. To be able to get the high current needed for this project, [mrjohngoh] started with an old microwave transformer. He removed the standard secondary coil and re-wrapped it with 1cm thick wiring to get maximum current out of the transformer. The ends of the coil wire attach to electrodes, which are made from a high-current electrical plug. The electrodes are mounted at the ends of a pair of hinged arms. The weld is made when the two pieces of metal are sandwiched between the electrodes and power is applied.

Spot welding isn’t just for joining two pieces of sheet metal. It’s also used for things like welding tabs onto battery terminals. The versatility and easy of building these welders make them one of the most featured tool hack we’ve ever seen.

Spot Welder; Don’t Buy It, Build It

Spot welders are super handy for making sheet metal enclosures for your projects. The problem is, commercial ones are rather expensive… The good news is, they’re actually really easy to make! This is [Caio Paulucci’s] first submission to Hack a Day, and it was a weekend project him and his father just finished.

A spot welder works by dissipating large amounts of heat in between two electrodes in the material you are bonding. It makes use of a transformer that converts mains voltage to a very low voltage, but high current energy source. The cool thing with this type of welder is it’s perfectly safe to hold onto the electrodes as the voltage is so low, you won’t get electrocuted. By running a super high current (generally >1000A @ ~1-2V) through a small surface area, you can super heat most materials hot enough to weld them together.

They can be made using the transformer from a microwave, some heavy duty welding wire (generally 2/0 or thicker), and a few other odds and ends such as wood, electrodes, and maybe a few nuts and bolts. At the most basic level, you are basically re-wrapping the transformer’s secondary coils to change the ratio to produce a low voltage, high current transformer.

Continue reading “Spot Welder; Don’t Buy It, Build It”

An autonomous boat across the Atlantic

While we may be waiting for unmanned drones to deliver a pizza, there’s already an unmanned ship plying the Atlantic on a transoceanic voyage. It’s called Scout, and it’s the product of about two years worth of work by a very close-knit group of friends.

Scout is a 12.5 foot ship constructed out of foam and carbon fiber loaded up with solar panels, electronics, an electric motor and a SPOT satellite tracker. The team has been working on Scout for the last two years now, and this last week the autonomous ship finally set out on its mission: a 3500 mile journey from Rhode Island across the Atlantic to Spain.

Right now, Scout is just over four days into its mission having travelled 90 miles from Rhode Island on its way to Spain. You can follow Scout on its journey on this very cool live tracking site.

Continue reading “An autonomous boat across the Atlantic”

DIY spot welder makes metalwork easy

At Hackaday, we’ve seen enclosures built out of just about every material. From wood, glass, epoxy resin, plastic, and even paper, all these different types of enclosures provide some interesting properties. Sometimes, though, you need an enclosure made out of metal and welding together steel cases isn’t exactly easy or cheap. [manekinen] came up with a really great solution to the problem of welding together sheet metal. It’s a very easy to build spot welder perfect for fabbing steel cases.

The core of the build is a transformer pulled from a Technics stereo amplifier. [manekinen] removed the stock secondary winding and rewound the transformer four turns of 35mm ² wire (about 2 AWG). This made the transformer put out 2.6 Volts a 1 kA – more than enough to weld 22 ga sheet.

For the control mechanism, [manekinen] put a limit switch on the electrode arm and wired that to a timer. A knob on the front of the welder allows him to vary the time the welder is on from 0 seconds to 4 seconds.

The results are fantastic – trying to rip apart a weld only results in the metal itself tearing; exactly what you want to see in a welder. It’s a great build made even more fantastic by the welder building its own enclosure.

Continue reading “DIY spot welder makes metalwork easy”