You get the world' cheapest and easiest Dual Pulse capacitive discharge welder capable of welding copper sheet to steel or other somewhat resistive metals!!!!!
The natural inductance of a CD welding pulse WILL activate a reed switch to
trigger the gate of the SCR in two parallel Capacitor/ SCR banks.
Then wired the higher voltage CD welder setup in parallel with that.
Then, use the regular foot switch to activate the SCR to the first
Here is my usual crummy drawing of the basic circuit:
Here are a few examples of the variety of materials you can weld with this thing:
All the welds above are what I'd call 'serviceable' ; some aren't quite as
good as I would like, but should hold up under normal use.
Oh, yeah.... It will work on batteries too: ;-)
Here are a couple of photos of my current setup. It isn't elegant, it
isn't pretty and it is pretty darn bulky.
It would be better if I 'hard wired' the second capacitor bank instead of using the alligator clips, but since I use the lab power supply on other things, I wanted to be able to just unclip it quickly.
The three parallel SCRs on the second cap bank are probably overkill... But I had a single one fail (for possibly unrelated reasons) during my early experiments, so I decided to err on the side of being sure they would handle the power. And the huge SCR on the first bank would probably handle 10000 watt second pulses, so it is definitely overkill. But I got a good deal on them all, so why not ?? ;-)
The really neat thing about this basic idea is that it is flexible and scalable.
You don't really have to use a higher voltage bank of 'real' Capacitors and a separate high voltage power supply;
That simple little reed switch will let you do dual pulse welding with, for instance:
Two decent 5F audio capacitors hooked up in the same way, but powered by one single 12V power supply... or even a car battery..... I'm not sure if you will be able to weld copper or silver with it, but just about any other metal should weld OK.
Or two banks of 'real' capacitors charged by one single heavy duty power supply.
Either way would be much neater and more compact: I just did it the way I did because that is what I already had available.... If I had been building from scratch I would have tried to be more elegant.
OH, And one more thing: My usual legal weasel words:
You will, of course, insulate all of the exposed metal, (except for the very tips of the electrodes), with electrical tape, heat shrink, self vulcanizing rubber tape or something safe, and submit it to Underwriters Laboratories for safety approval before you plug it in and try to use it, won't you?
If you short it out, anywhere other than the electrode tips on semi-resistant material (steel, nickel etc.) you will get a big spark, and possibly a major meltdown, fire, death and destruction.
Just because I don't show something or write about it or am completely ignorant about it myself, doesn't mean it should be ignored.
Lithium batteries especially are inherently hazardous. Understand the chemical and electrical characteristics of them before you even touch one, much less try to weld one, charge one or use one in any device not specifically designed for the specific battery. They can blow up, burn, stink, release poisonous gasses, fluids, particulates and solids. If you swallow one, it will probably kill you in several unpleasant ways. Do not stick them in any other bodily orifice.
Nickel Metal Hydride, Nickel Cadmium, Alkaline, Silver Oxide, Carbon Zinc, Zinc Air, and Lead Acid batteries are only slightly less dangerous in general. Don't abuse them either.
It is very likely that I forgot something important; So unless you absolutely know what you are doing around electricity, electrical components, hot and sharp tools, ask an expert licensed electrician and/or electrical engineer. Make sure that all your wiring is up to code, and get it inspected by your local code and zoning authorities. If disaster befalls you from following the previous and following instructions, don't call a lawyer and try to sue me. I spent the last of my money on parts for this thing and on batteries. I'm broke, and there will be nothing for you or your lawyer.
Finally got my nickel sheet from Admiral
Steel. They were out of stock on the .01 thickness, and didn't see fit to let me know about it until I asked after a couple of weeks of waiting with no delivery and no notice. So, I told them to send the .005 instead. About a week later, I finally got it. (I still want to try the .01 thickness, but that will have to wait.)
Please don't try to contact me for more information. Everything I know about this is covered on these pages. For more ideas and information go to: http://endless-sphere.com/forums/viewtopic.php?f=2&t=2633&hilit=welder The guys over there have expanded on my design and tried different approaches. Maybe you can find out what you want to know over there.
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website copyright © Robert L. Thompson / LEDhacks.com unless