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Making a capacitive discharge spot welder is a little more challenging than I had anticipated.

Vaizdas
 For the longest time I've wanted to build a capacitive discharge spot welder for battery tabs. One problem being is that I couldn't afford or find suitable capacitors. Building one with new capacitors costs way more than I'm willing to pay for what in reality is just an experiment. So you can imagine my joy when I got a whole box of capacitor banks completely for free! Yes, whole capacitor banks. These come from forklift motor drivers that blow up beyond repair. The drives that these banks came from have their capacitors on a separate board, making it super easy to pull them out and use on something else. These banks consist of 30 electrolytic capacitors that are rated for 63V and 680µF each and are all connected in parallel in a large capacitor bank. Each bank has two plates bolted to it that each serve as output terminals and have aluminum blocks on them with M8 tapped holes, ready to bolt to. In total this comes to just over 20mF of capacitance and at 60V it would hold ...
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Engineering a part nobody asked for to fix an obsolete welder you can't buy anymore. The DIY ESAB inverter module saga.

Vaizdas
 Working in the welding business has its benefits. Sometimes you get to keep old welders that are deemed unrepairable. Some times the machine is too cheap to repair so it's uneconomical. Other times the part is no longer sold, so sourcing one is not possible anymore. Well I've happened to receive two welders that are both too expensive to repair and have no parts available. Well, the latter is not entirely true, because the part to fix the welder can still be bought. Unfortunately this part alone costs more than the welder is worth and is increasingly hard to source from the manufacturer. The welders in question are the ESAB CADDY, namely the TIG2200i and another one with more buttons but still based on the same inverter platform.  These welders have a funny thing about them - all of the inverter power semiconductors are located entirely in a single module, named the PM1.   This module does the input rectification, power factor correction, soft start and has the 2 sw...
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Repairing a ruined moped variator thread with a welder and an angle grinder.

Vaizdas
 My little bro was enjoying his new-ish moped that we got running recently and, while riding around with his friends, had it break down in the worst way. He called me up and told me that some nut on some shaft came off and won't go back on again. I told him that perhaps it's a reverse thread, yet it won't go on either way. Okay so we got a video call going on and through the few pixels that I saw I could tell that this is not an easy fix my brother could do by himself. So during the weekend I came back home and took a closer look at what was going on. As it turns out the thread on the end of the crank shaft, which holds the variator assembly on, has been completely wrecked. Quite unusual until I noticed that the nut and the crankshaft had different pitch threads. The crankshaft had a fine pitch thread and the nut was a standard M10x1.5 nut. Some monkey thought that forcing a different nut on was the right choice. Oh boy. Now, the correct way to go about this would be to buy...
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