[sweetfarms]

Does a plasma cutter do better than acet / oxy cutting torch on rusty steel? I do repairs on old rusty farm equipment and sometimes it is a pain trying to cut through old rusty welds and pitted steel (starts and stops). I was wondering if you would have to do as much cleaning before cutting with a plasma? Thanks

[nickn372]

They are much worse with rusty steel. Your best bet is to invest $10 in a good knotted wire wheel and brush off the rust scale before using the torch or plaz. A plaz needs a good ground and good contact from the gun to the base metal. Needs to be about as clean as you would need to have it to MIG weld the steel.

[GWD]

Hmmm....I haven't had much trouble cutting rusty metal and cut quite a bit of it on the farm.

However and as stated, a good ground is very necessary. Find someplace where a grinder can get down to bare metal and attach the ground clamp.

As far as the plasma arc goes, once it starts cutting the electrical circuit is completed through where the arc is cutting - it is bare metal. I haven't had trouble starting the arc but a little nick of bare metal at the start with a file may help if someone runs into some really heavily rusted pieces.

[Otto Nobedder]

On rusty carbon steel, I have to say that when it's just surface rust, plasma and oxy-fuel work about as well. If you're dealing with layers of rust scale (which often accumulates when moisture gets under paint), however, you'll have real problems with either, and you'll wear yourself out with a grinder. Use a pneumatic needle-scaler or an air-chisel to knock the scale off. If you "cook" the moisture out of the scale first with your torch, It'll come off much easier.

Steve

[sweetfarms]

Thanks for the tips!!!