Spot welding should easier than it looks. After all, it’s just a lot of current in a short time through a small space. But it’s the control that can make the difference between consistently high-quality welds and poor performance, or maybe even a fire.
Control is where [WeAreTheWatt]’s next-level battery tab spot welder shines. The fact that there’s not a microwave oven transformer to be seen is a benefit to anyone sheepish about the usual mains-powered spot welders we usually see, even those designed with safety in mind. [WeAreTheWatt] chose to power his spot welder from a high-capacity RC battery pack, but we’d bet just about any high-current source would do. The controller itself is a very sturdy looking PCB with wide traces and nicely machined brass buss bars backing up an array of MOSFETs. A microcontroller performs quite a few functions; aside from timing the pulse, it can control the energy delivered, read the resistance of the 8AWG leads for calibration purposes, and even detect bad welds. The welder normally runs off a foot switch, but it can also detect when the leads are shorted and automatically apply a pulse — perfect for high-volume production. See it in action below.
There may be bigger welders, and ones with a little more fit and finish, but this one looks like a nicely engineered solution.
Continue reading “A Battery-Tab Welder with Real Control Issues”
[Jim Conner]’s DIY tab spot welder is the sweetest spot welder we’ve ever seen. And we’re not ashamed to admit that we’ve said that before.
The essence of a spot welder is nothing more than a microwave oven transformer rewound to produce low voltage and high current instead of vice-versa. Some people control the pulse-length during the weld with nothing more than their bare hands, while others feel that it’s better implemented with a 555 timer circuit. [Jim]’s version uses a NodeMCU board, which is desperately overkill, but it was on his desk at the time. His comments in GitHub about coding in Lua are all too familiar — how do arrays work again?
Using the fancier microcontroller means that he can do fancy things, like double-pulse welding and so on. He’s not even touching the WiFi features, but whatever. The OLED and rotary encoder system are sweet, but the star of the show here is the 3D printed case, complete with soft parts where [Jim]’s hand rests when he’s using the welder. It looks like he could have bought this thing.
Continue reading “Beautiful DIY Spot Welder Reminds Us We Love 3D Printing”
Ho-hum, another microwave oven transformer spot welder, right? Nope, not this one — [Kerry Wong]’s entry in the MOT spot welder arms race was built with safety in mind and has value-added features.
As [Kerry] points out, most MOT spot welder builds use a momentary switch of some sort to power the primary side of the transformer. Given that this means putting mains voltage dangerously close to your finger, [Kerry] chose to distance himself from the angry pixies and switch the primary with a triac. Not only that, he optically coupled the triac’s trigger to a small one-shot timer built around the venerable 555 chip. Pulse duration control results in the ability to weld different materials of varied thickness rather than burning out thin stock and getting weak welds on the thicker stuff. And a nice addition is a separate probe designed specifically for battery tab welding — bring on the 18650s.
Kudos to [Kerry] for building in some safety, but he may want to think about taking off or covering up that ring when working around high current sources. If you’re not quite so safety minded, this spot welder may or may not kill you.
Continue reading “Dual-Purpose DIY Spot Welder Built with Safety in Mind”
When we think of an Electric Arc Furnace (EAF), the image that comes to mind is one of a huge machine devouring megawatts of electricity while turning recycled metal into liquid. [Gregory Hildstrom] did some work to shrink one of those machines down to a practical home version. [Greg] is building on work done by [Grant Thompson], aka “The King of Random” and AvE. Industrial EAFs are computer controlled devices, carefully lowering a consumable carbon electrode into the steel melt. This machine brings those features to the home gamer.
[Greg] started by TIG welding up an aluminum frame. There isn’t a whole lot of force on the Z-axis of the arc furnace, so he used a stepper and lead screw arrangement similar to those used in 3D printers. An Adafruit stepper motor shield sits on an Arduino Uno to control the beast. The Arduino reads the voltage across the arc and adjusts the electrode height accordingly.
The arc behind this arc furnace comes from a 240 volt welder. That’s where [Greg] ran into some trouble. Welders are rated by their duty cycle. Duty cycle is the percentage of time they can continuously weld during a ten minute period. A 30% duty cycle welder can only weld for three minutes before needing seven minutes of cooling time. An electric arc furnace requires a 100% duty cycle welder, as melting a few pounds of steel takes time. [Greg] went through a few different welder models before he found one which could handle the stress.
In the end [Greg] was able to melt and boil a few pounds of steel before the main 240 V breaker on his house overheated and popped. The arc furnace might be asking a bit much of household grade electrical equipment.
Continue reading “Electric Arc Furnace Closes the Loop”
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.
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.
There are a lot of neat toys and accessories that rely on 3D printing filament. The 3Doodler is a 3D printing pen, or pretty much an extruder in a battery-powered portable package. You can make your own filament with a Filastruder, and of course 3D printers themselves use up a lot of filament. [Bodet]’s project for this year’s Hackaday Prize gives those tiny scraps of leftover filament a new life by welding filament together.
The EasyWelder [Bodet] is designing looks a little bit like a tiny hair straightener; it has a temperature control, a power switch, and two tips that grip 1.7 or 3mm diameter filament and weld them together. It works with ABS, PLA, HIPS, Nylon, NinjaFlex, and just about every other filament you can throw at a printer. By welding a few different colors of filament together, you can create objects with different colors or mechanical properties. It’s not as good as dual extrusion, but it does make good use of those tiny bits of filament left on a mostly used spool.
Since the EasyWelder can weld NinjaFlex and other flexible filaments, it’s also possible to weld NinjaFlex to itself. What does that mean? Custom sized O-rings, of course. You can see a video of that below.
Continue reading “Hackaday Prize Entry: Welding Plastic Filament”
A few weeks ago, the folks at the 23b hackerspace held Sparklecon, an event filled with the usual infosec stuff, locks and lockpicking, and hardware. A con, of course, requires some cool demonstrations. They chose to put a pickle in an arc welder, with impressive results.
This build began several years ago when the father of one of 23B’s members pulled off a neat trick for Halloween. With a cut and stripped extension cord, the two leads were plugged into a pickle and connected to mains power. The sodium in the pickle began to glow with a brilliant orange-yellow light, and everyone was suitably impressed. Fast forward a few years, and 23b found itself with a bunch of useless carbon gouging rods, a 200 Amp welder, a pickle, and a bunch of people wanting to see something cool.
The trick to making a pickle brighter than the sun was to set the arc just right; a quarter of an inch between the electrodes seemed optimal, but even then pickle lighting seems very resilient against failing jigs made from a milk crate, duct tape, and PVC. Video (from the first Sparklecon, at least) below.
Continue reading “Sodium Pickle Lights”