I'm playing around with a circuit, I want to produce a spark reliably. If I take two wires and just barely touch them, then discharge a capacitor across the junction I get a nice spark. However this only happens once, maybe twice before the metals seem to fuse together at which point I cannot get a spark. I want to learn more about this, why is there a spark initially? Is it because the contact area is very small? And is there any way of building a junction that can produce this effect repeatedly?