In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.Subject: Re: Novice Questions
Date: Jan 29, 7:16 pm
Poster: Tom LigonOn Jan 29, 7:16 pm, Tom Ligon wrote:
>7. We were planning on buying a small spot welder for grid construction until we found there is no such animal. The posting on building a spot welder was very helpful. I've got several fair sized capacitors rated at 3000 ufd @ 50 VDC. It seems too simple to just get a 50 volt DC power supply and hook it up to the capacitor and the spot welding electrodes. It seems we could easily get a nasty burn from this setup if we're anything other than totally alert. What else are we not understanding here being novices?
>
The spotwelder I use is a very old reconditioned commercial model, rated at up to 80 watt-seconds (joules). It uses electrolytic caps charged to up to about 400 volts, then discharges them thru a step-down transformer to get high current at low voltage. 50 volts is safer than 400, but still possibly lethal (you can get a tickle at 24 volts and can conceivably kill yourself as low as 35 volts). Try running the caps directly at 24 volts or so if you can find a small supply to charge them, or step the voltage down with a transformer (good junkyard item).
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Regarding the hydrogen issue, you might "cheat" by getting someone to give you an occasional wiff of hydrogen you could store in your cylinder. Backfilling an existing tank to 7 psig is not technically legal, but it is safe. If it leaks it is no more dangerous than a bad case of gas, and you would not need a regulator.
Tom