Plasma cutting galvanized steel. Water table or downdraft?!

[C Bad]

hey, I'm new to the CNC scene. From what I know, welding galvanized steel creates some toxic fumes. Are there any dangers of plasma cutting galvanized steel on a water table? Is there a possibility of something similar as to explosive hydrogen pockets being trapped between the water and plate as in cutting aluminum?
I'd rather put together a water table than a downdraft system. I will mainly be cutting mild steel and galvanized.
Thanks.

[jimcolt]

While plasma /cnc machines that are built for cnc plasma cutting of galvanized steel for the HVAC market all use downdraft tables (keeps the water stains off the sheets)....there is no reason why galvanized cannot be succesfully cut on a water table...the water sould be right at the bottom of the sheet.

When cutting of aluminum on a water table there is a reaction of the aluminum oxide particles that settle in the bottom of the table...these particles absorb oxygen from the water...leaving hydrogen. Hydrogen bubbles rise in the water and easily and safely dissipate in the air under normal conditions...however if there is a place that can trap the hydrogen and a large pocket accumulates...then there could be an explosion issue. The zinc from the galvanizing coating will not do the same thing.

Jim Colt

[GrahamSwindley]

I am sure that a water table is best for nearly all small general purpose cutting tables. You would need a HUGE air flow to get rid of all the tiny particles caused by plasma cutting- water just mops them up. Beware of possible Legionnaires disease and change water regularly - in the UK we have to use a chemical bacterial inhibitor. I also use a corrosion inhibitor in the water -helps if you leave mild steel in for a few haours.

Graham