Longer consumable life with flooded sheet?

[arnegrant]

I am curious if anyone runs flooded sheets, with the sheet fully under water here?

If so, do you see longer consumable life?

I am pretty good at keeping the water level right at the bottom of my sheet. I let it get a little low (I was tired) and I noticed the consumables burned up faster than normal.

I have weight capacity, and the bath tub would allow for most of what I cut to be fully under water - just curious if that would help or not with consumable life.

Or if anyone has any experience with this.

I could do it, but it would make changing the sheets way more time consuming (I would have to drain and fill the table to get to the top of the slats to clean them off so the sheet sits square).

Easy enough to fill but I would have to set up a drain capacity - I don't have my table drain plumbed to anything at the moment.

[weldguy]

That would not be a good idea for air plasma, I would stick with what your doing.

[arnegrant]

Ok

Thanks

[PlasmaDon]

I have done it, with a torchmate table.
Not for consumable life, but to test if I could keep distortion down.

I used to program nesting 35 years ago that ran it that way, very old very large plasma
table, IIRC 400 amps.
They ran the water up over the plate mainly for noise & arcflash.
They also added powdered black die to the water, and had a ring nozzle affair to keep everything
shielded with water.

[acourtjester]

I think you would have a problem if you are using an Ohmic sensor on the torch.

[PlasmaDon]

I think you would have a problem if you are using an Ohmic sensor on the torch.

Why think when you can try ?

Put some water in a tuna fish can, set it on the table, run torch down into it.

[acourtjester]

Ok I am sure as I have a problem with Ohmic sensors when water splashes up on the torch and it needs to be dried off before the circuit will not show it is tripped. This is not a large problem but it does happen, completely under water makes a real problem, Is that better? Yes there is a system to cut under water Hypertherm has a high powered setup.

[PlasmaDon]

Ok I am sure as I have a problem with Ohmic sensors when water splashes up on the torch and it needs to be dried off before the circuit will not show it is tripped. This is not a large problem but it does happen, completely under water makes a real problem, Is that better? Yes there is a system to cut under water Hypertherm has a high powered setup.

Interesting feedback, thanks for that.
The torchmate I was running wasn't affected.
How Hypertherm got around it 4o years ago (on that machine I used to nest to) would be interesting reading.
I'm wondering if some ohmic detectors are more sensitive than others, simply take a cheap DMM and set it on the lowest
ohm scale and put the probes in a glass of water. You've got to go up a few scale settings to any kind of reading.

I know there are some patents from hypertherm about the water ring, not to be cornfused with the ones
on water injection (radially).

[SegoMan DeSigns]

I'm with Tom on this one especially when you have anti-rust additives in the water (like laundry soda). I would be more concerned about moisture in the cutting air than cutting parts under water for consumable life.

[acourtjester]

A way around this is to use a Floating head switch, this triggers the plasma by movement of the torch not Ohmic contact.

[kn612]

Are there any negatives to cutting underwater with an air plasma besides not being able to use ohmic sense? I can't try it on my current table, slats are too high but I think I can flood it on the table I'm working on to replace it.

[PlasmaDon]

A way around this is to use a Floating head switch, this triggers the plasma by movement of the torch not Ohmic contact.

That's a good idea.

[PlasmaDon]

Are there any negatives to cutting underwater with an air plasma besides not being able to use ohmic sense? I can't try it on my current table, slats are too high but I think I can flood it on the table I'm working on to replace it.

As I said before, I've done it on a torchmate, it does work, but I didn't see any real benefit.

I also did it with oxy, and the preheat time was crazy long, the slag was tenacious to get off.

On Oxy I did it because I was using up very small pieces of scrap, and didn't want the part to move.
With the slow (10 ipm) cutting rate, by the time it chugged around the part, the kerf opened up, showing the main plate
had moved with all the heat, when not running submerged.

I find keeping the water about 1/2'" under the sheet works best.
Higher and you've got the slag problem and splashing on your ways & rack gear.
Lower, and it makes steam that rises up and coats the machine as well.

Can you shear up some shorter slats ? or does your slate holders (comb looking ribs) come up too high as well ?

[PlasmaDon]

GEDC0395.JPG

Dug out a pix of my Oxy days.
here is 1/2" plate underwater, IIRC about 1/4" over top of the plate

But this has wandered off the OP, into Oxy.

I don't know of any shops running water over the plate plasma anymore.
As far as extending consumable life, I don't think that was the objective in the places I've seen it done.