Water depth, slats, and underwater cutting
- bentiggin
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08 Apr 2026 01:26 #345303
by bentiggin
Water depth, slats, and underwater cutting was created by bentiggin
I have a 20'x6'(6m x 1.8m) plasma that I'd like to convert to a water table. I plan on having a reservoir underneath that gets filled/drained with air pressure.
I have seen some water tables that have the water at the bottom of the sheet, but I've yet to see one that cuts underwater. How deep underwater does the plate need to be?
I guess I'm trying to figure out how deep the pan should be and how tall the slats should be.
The way the table is, it'd be fairly easy to make a 4"-6"(10-15cm) deep pan. It wouldn't be too hard to go deeper, but we're already at 100's of gallons and thousands of pounds at that depth.
My main reason for a water table is smoke control, but minimizing warping on sheet metal would be a plus.
I'm not certain I want underwater cutting, but I like the idea of it.
Some other questions.
How to keep sediment out of the reservoir? I thinking of having the last few inches of the pan go directly to the reservoir, with a sort of lip and screen. The upside of this would be easier fabrication, but that would also make the reservoir/pan one piece. Alternatively, I could use pipes, but I still don't know how I'd deal with sediment and I'm sure that would really increase the drain/fill time.
The building the plasma is in is unheated so I need a heater to keep the reservoir from freezing. I think a screw in or tri clamp element like you'd see in a residential water heater would be the best choice. How would I go about controlling the temp? I don't wanna reinvent the wheel if there are already off the shelf solution if anyone has a suggestion.
Any insights are appreciated.
I have seen some water tables that have the water at the bottom of the sheet, but I've yet to see one that cuts underwater. How deep underwater does the plate need to be?
I guess I'm trying to figure out how deep the pan should be and how tall the slats should be.
The way the table is, it'd be fairly easy to make a 4"-6"(10-15cm) deep pan. It wouldn't be too hard to go deeper, but we're already at 100's of gallons and thousands of pounds at that depth.
My main reason for a water table is smoke control, but minimizing warping on sheet metal would be a plus.
I'm not certain I want underwater cutting, but I like the idea of it.
Some other questions.
How to keep sediment out of the reservoir? I thinking of having the last few inches of the pan go directly to the reservoir, with a sort of lip and screen. The upside of this would be easier fabrication, but that would also make the reservoir/pan one piece. Alternatively, I could use pipes, but I still don't know how I'd deal with sediment and I'm sure that would really increase the drain/fill time.
The building the plasma is in is unheated so I need a heater to keep the reservoir from freezing. I think a screw in or tri clamp element like you'd see in a residential water heater would be the best choice. How would I go about controlling the temp? I don't wanna reinvent the wheel if there are already off the shelf solution if anyone has a suggestion.
Any insights are appreciated.
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- tommylight
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08 Apr 2026 02:34 #345304
by tommylight
Replied by tommylight on topic Water depth, slats, and underwater cutting
I have some suggestions, you wont like them:
-Reservoir is utterly useless, unless you intend on using the machine about once every month or two, simple physics water evaporates and does so much more when it has a nozzle spewing 10000 degrees heat into it all day long. During summer here (35-40C) and heavy use, i have to refill every 2 or 3 days, meaning 2-4cm of water level is gone in that time. In general bigger table = less water level drop daily.
Having a water tap directly into it would be much more useful.
-You can cut underwater, easily, do not go above about 1-2cm deep with the torch, and that absolutely requires drying the torch whenever you do not use it as it will rust, quickly and badly. Everyday use should be fine.
-Roughly 15 cm deep would be nice (a lot less spill/spray over, 10 is very usable (mime are usually 10-12cm deep), and i would not go lower than 5cm on slats for up to 100A, 10cm for 200A and above.
-as for reservoir issues, see first paragraph.
Also, I might be utterly wrong here, but, stop watching youtube experts that built a single machine and now dispense advice like they are the "be all-end all".
-Reservoir is utterly useless, unless you intend on using the machine about once every month or two, simple physics water evaporates and does so much more when it has a nozzle spewing 10000 degrees heat into it all day long. During summer here (35-40C) and heavy use, i have to refill every 2 or 3 days, meaning 2-4cm of water level is gone in that time. In general bigger table = less water level drop daily.
Having a water tap directly into it would be much more useful.
-You can cut underwater, easily, do not go above about 1-2cm deep with the torch, and that absolutely requires drying the torch whenever you do not use it as it will rust, quickly and badly. Everyday use should be fine.
-Roughly 15 cm deep would be nice (a lot less spill/spray over, 10 is very usable (mime are usually 10-12cm deep), and i would not go lower than 5cm on slats for up to 100A, 10cm for 200A and above.
-as for reservoir issues, see first paragraph.
Also, I might be utterly wrong here, but, stop watching youtube experts that built a single machine and now dispense advice like they are the "be all-end all".
The following user(s) said Thank You: spumco, NWE
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