From a book entitled " Non-traditional machinging Procsesses ",
" The ECM process requires low voltage DC. Voltages from 5v to 15 v
are usually used but may go as high as 30 v in certain cases.
Currents from 100 to 20,000 amp are being used with even higher
currents being considered for the future.

A welder would have a higher voltage than you need, but might work for
doing some experimenting. You might also consider Microwave Oven
transformers with a rewound secondary.

Dan