Question - Re: Plasma Cutter

[Oonrahnjay]

      To do plasma cutting on a bus (frame, etc.), would you isolate/disconnect electronic components, like you'd do with an arc welder?   
      Thanks,  BH

[Lin]

Theoretically, I would.  It is the safest thing to do.  But I have been known to be lazy and did once cut a hole for a latch with a plasma cutter without disconnecting anything.  There were no problems.  Thinking back on things, I believe some of the welding done on my bus was also done without taking precautions.  My guess is that most times you will not have a problem as long as the distance between the ground and the working area is small.  However, using the most-times rule is not really safe practice.

Of course my bus is an old mechanical unit.  If you have those new fangled electronics, you might want to be extra cautious.  One other note, when Don was working on my bus some years ago we decided to plasma cut some old stuff away.  Don let me do the cutting, but he was right next to me ready with a fire extinguisher in case the oil and grease accumulation decided to ignite.  Even without a helper, it might be a good idea to keep an extinguisher within reach.

[bevans6]

I would just provide a really good ground very near the plasma cutter.  Unless you remove the electronics bodily from the vehicle it's totally hard to really isolate them.  I've welded on a ton of stuff and never had an electronic issue yet, touch wood...

Brian

[Scott & Heather]

FYI, my coach manual specifically says to disconnect the batts before welding and I think even unplug the engine ecm plugs too.


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[luvrbus]

Mine is a non transferred arc so I don't worry about it ,the arc is inside the nozzle then the plasma gas does the cutting

[goldgiter]

As long as the ground is close to the work you should be ok.

Wes

[oltrunt]

I have a mid size Miller plasma cutter.  The instruction manual recommends disconnecting the battery and computer prior to cutting.  I'm good about the battery and not so good about the computer.

As a personal note, I find that if I position myself between the ground or the machine and the cutting torch and strike an arc to cut, I immediately feel a strange nearly compressive sensation in my chest and my head feels like I stood up too fast.  I'm fine as long as I don't assume the described position.  I expect that all these machines produce a powerful magnetic field and it is that which disturbs my equalibrium.  I also have a light duty Esab brand plasma cutter and I'm OK with it unless I'm right on top of the ground wire while I cut.  I'd be interested to know if any of the rest of you have had a similar experience with a plasma cutter.  I should add that an arc welder produces no such sensation though I know there are magnetic fields at play because I can see the grinding slag orient along the ground wire where it lays on the concrete floor.  Without going into the complete tale of how I discovered this I'll just mention that I'm able to set off some car alarms simply by raising my arms when I am near the alarm box--no touching, no noise, wierd huh?

All that to say it seems like a good idea to disconnect the battery and unplug the computer before using a plasma cutter.  Jack

[dgorila1]

......  Without going into the complete tale of how I discovered this I'll just mention that I'm able to set off some car alarms simply by raising my arms when I am near the alarm box--no touching, no noise, wierd huh?
  Jack

Were you ever abducted by aliens? Used for experiments while in the military? Grew up near a nuclear test range or waste facility? Very interesting..........hmmmmmmmmmmmmmmmm......

[Oonrahnjay]

     I appreciate all the comments.  It confirms what I thought but lots of times that's valuable.  Many thanks.