Question about using a plasma cutter on rusty boiler plate

I had to cut out a section of 1/2 inch boiler plate in an old power plant near Gary last week. The rust was so bad I figured my Hypertherm 45 would struggle, but I tried running it at 40 amps instead of full power and it cut clean as could be. Anyone else found that dialing down the amps helps with corroded steel?

3 comments

3 Comments

the_jessica19d ago

Rust is non-conductive so lower amps stops it from arcing out before hitting clean steel.

harpery4719d ago

Huh, you're lucky it didn't just sputter out with that much rust.

price.gavin18d ago

Rust that bad usually means you're fighting it the whole way. @the_jessica is right about the amps helping, but man, that thing must've been on its last legs.