Hey I’m making a mini welder for small projects. I’m going to make it out of a few transformers and a car battery. It have an aspect of portability, due to it being on a cart.
Does anyone have extra microwave transformers or car batteries laying around?
If you go to the electronics recycling depot on Evans ave. and you ask the guys nicely they may let you grab the microwaves for the transformers. It’s very YMMV and if the boss is around, it won’t happen. If the microwaves are already on the pallet nicely stacked up, it won’t happen either. Best chances of success is with stuff that has been dropped off recently and is still sitting on the carts or the floor.
If it’s something you want to do (ask for scrap for parts) frequently, it helps if you bring them water or pop when you are dropping stuff off.
I have gotten microwaves, an audio amp, an lcd tv, a plotter and a handful of large inkjets from them that way. (I’m addicted to taking stuff apart).
You could also check with Freegeek. I’m not sure if they get that kind of stuff.
A spot welder?
You can’t use a transformer on unless there’s a delta flux on the primary, DC (car batteries) only produce a delta when you first connect it, so you’d only get a small pulse of current.
As for the actual need for transformers, car batteries are already at the general voltage needed to weld, 12-40 volts. It’s quite common to see off-roaders wire up 3 car batteries to fix a broken suspension.
I’m very interested in this project, (want a small spot welder for sheet metal boxes). I have two ballasts from my old fish tank lights, they seem fairly heavy so they might be powerful enough?
Unfortunately, ballast transformers aren’t useful for these purposes. (they are designed to provide a high voltage at very low, almost nill loads, in order to start the ionization in the fluorescent light, and then, once the light bulb starts drawing power, the transformer core saturates and the voltage drops significantly).