PSU shutting off when used for electrolysis.

[emtor]

I'm having a ATX computer PSU that I use for electrolysis purposes, namely for giving knives a nice black patina.
The electrolyte is a mix of water, tablesalt and vinegar, and the cathode is a tin-can containing the electrolyte while the immersed knife acts as the anode.
Voltage from the PSU is 12 volts, and immersing the knife in the electrolyte gives an ohm reading of 25 ohms between the can and the knife which should draw approx. 0.5 amps from the PSU.
Problem is the PSU shuts down if the knife is fully immersed (not touching the anode of course).
Provided the PSU is OK, what could be the reason for the shutdown? The PSU is rated for 10 amps so obviously something is going on here.
Could it be that my setup acts as a capacitor and that my ATX PSU isn't happy driving a capacitive load?

[Pauldf]

I can't see it being capacitive, a capacitor will just charge up and the current will go down as a result.
Maybe worth getting a proper power supply unit like a bench PSU where you can adjust the voltage and watch the current.