Miniature Percussion Welder

Percussion welding has been around for over a century, but even today is not well known. Welding is achieved from an arc created by a short electrical discharge between the welded parts, while the part are rapidly approaching each other. The discharge happens a millisecond or less before the parts come in contact. The arc melts the tips of the approaching parts, so when thy come together they fuse.
Practically in all case the arc is created by a capacitor discharge. For welding small parts in order of 1mm and less there really just to options to initiate the discharge before the parts come in contact. One is using high voltage to charge a high voltage capacitor. The voltages are between 2KV to 3KV creating the discharge when the parts are about 1-2mm away.
Another option is to use a lower voltage capacitors and to initiate the arch by superimposing high frequency high voltage on the capacitor voltage.
In both cases we deal with high voltages requiring substantial insulation between the parts holders as well as a high voltage risk.
This demonstration is using external ionizer. As such the two holders are only at the capacitor voltage and this can be as low as 60V or even less.
The weld can join many dissimilar metals and One application can be welding broken pivots in fine mechanisms, watches and clocks, for example. Pivoting traditionally involves drilling into the arbour of the broken pivot and pressing a wire to be machined to size. This is not always an easy procedure when, for example, the pivot is 0.2mm diameter and the arbour 0.5mm.
Based on this prototype I hope to construct the welder. I am using a watchmakers lathe with the head and tail-stock insulated from each other. The release of the spring loaded tail-stock will be electromagnetic and a fraction of a second after the ionizer.
Right now I am using 450 microfard, 420V capacitor. I intend yo use larger 60V -100V capacitors in the future.

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