a few questions on plasma water tables

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Hello all, great forum here!  i am in the process of building a water table for the plasma.  There are some cool projects on here and they are very inspirational.But its the super basics that i have questions about!water depth?  is there a mininum? my pan is 4" deep so I figure about 3 and a bit of water. is that enough?how far below what I am cutting should the water level be?i would also like it to not dissolve into a blob of rust!  can i leave it full or should i drain it when not in use?  I guess i also need to add something to the water...any suggestions?
Reply:HII can tell you about mine it is 4" deep too with 3-1/2" slat height I have about 2-1/2" to2-3/4" of water and it works fine, More water means more bubbles and water on the metal.  I'm running 80 PSI for the plasma.I use borax detergent in the water and more rust I just add water when needed been it there for a few months still ok.[ame]http://www.youtube.com/watch?v=WdG9_ZQSxCg&list=UUrWyAGIpMmQfMwq0KTKpuRw&  index=1&feature=plcp[/ame]
Reply:A couple of comments:-If the water is in contact with the plate, there is less smoke/fumes.-If water is a couple of inches below the plate....the cut quality is better, there is less splashing on the plate and the moving parts of the machine.-Many industrial applications (machines designed specifically for using water tables) cut submerged....with the top of the plate 1 to 3 inches under water....no smoke, no fumes, reduced Ultraviolet, no noise.-Water contacting the plate, even splashing....affects cut quality. Expect a rougher edge and higher probability of dross.-Industrial water tables have a pneumatic water level raise/lower setup. This allows you to fine tun cut quality/fume control. Also allows for easy cleaning...lower the water completely so you can clean the sludge and scrap drops out.......also helps you to retrieve small parts that drop.Jim Colt   Hypertherm Originally Posted by MJMetalworksHello all, great forum here!  i am in the process of building a water table for the plasma.  There are some cool projects on here and they are very inspirational.But its the super basics that i have questions about!water depth?  is there a mininum? my pan is 4" deep so I figure about 3 and a bit of water. is that enough?how far below what I am cutting should the water level be?i would also like it to not dissolve into a blob of rust!  can i leave it full or should i drain it when not in use?  I guess i also need to add something to the water...any suggestions?
Reply:Awesome thanks for the feedback guys!bought a drain plug for the bottom of the pan yesterday,  will hopefully be building the stand for it today.I am trying to build it just as a manual water table for now but trying to make it straight/square enough and sturdy enough that I can add the bits to turn it into a CNC set up later!
Reply:I did not realize that you were planning to use a water table for hand cutting. In that case....the water sould be 6 or more inches below the bottom of the plate.....you should not be using a hand torch in a situation with water splashing on the torch.Jim Colt Originally Posted by MJMetalworksAwesome thanks for the feedback guys!bought a drain plug for the bottom of the pan yesterday,  will hopefully be building the stand for it today.I am trying to build it just as a manual water table for now but trying to make it straight/square enough and sturdy enough that I can add the bits to turn it into a CNC set up later!
Reply:thanks Jim, thats the kind of 'don't kill yourself' info I need!I am hoping that I wont be using it as a manual cutter for too long!the main reason I am doing a water table is dust control, I don't have very good ventilation in the shop and the dust from using the plasma is not to nice! I think I will just put an inch of water in bottom of the pan for when manual cutting for now.based on what you said Jim I will raise up the cutting surface another inch or 2 which should give me 3-4 inches beneath my cut.  once i start setting it up for motors and gear I will drop the bed back down.most of the videos of plasma cutters running cnc on the web show the water almost up to whats being cut...so I am glad I asked.thanks Jim
Reply:Jim, does the splashback from plasma cutting get worse as you move to higher currents and thicknesses?90% of what I will be cutting will be 16g sheetmetal (got the plasma since I dont have room for a shear)I think I can get about 5 Inches below what I am cutting now without making a new pan
Reply:Yes...the affect is more on thicker materials....probably thicker than 10 gauge.Jim Colt Originally Posted by MJMetalworksJim, does the splashback from plasma cutting get worse as you move to higher currents and thicknesses?90% of what I will be cutting will be 16g sheetmetal (got the plasma since I dont have room for a shear)I think I can get about 5 Inches below what I am cutting now without making a new pan
Reply:thanks so much!