Ok, thought I'd spelled it out, but didn't. Here's the blade welder specs:

220 volts
20 amp
60 Hz
1 phase
Instantaneous KVA 4
Continuous KVA 5 or .5, the potential decimal point being high enough
it's not clearly a decimal point. But if instantaneous means inrush,
then maybe .5 KVA continuous makes sense.

Sounds like I'd best find a local electrician that can give me a
definitive answer.
Or weld up a life time supply of blades before I go...G

Jon