Water table depth for submerged cutting?

[Knut]

Looked at Graybeards pics of his water table on Yahoo. Didn't find much info on submerged cutting there or here. Lots of dead ends hits on cnczone, the search words bring back just about every thread. Most deal with water trays.

With 5hp of air pushing through the kerf, a great deal of air movement must be involved under the sheet. That will need some depth to handle the flow. Curious as to how much depth is truly needed as my table has to tip up for storage. No matter how deep, it would appear that six drop down support legs will be necessary to support the water and level the table with such a large load on it. The shallower the better for me. A 5.5" water depth would work well for construction IF that is deep enough to disperse the gases. That makes my tanks mounted under the table smaller also. That would mean making tanks of 2.4cuft/linear ft of table, about the max I can sneak in there.

My intention is to cut mostly thin materials, so a submerged cutting table is very desirable. After watching one work at the local collage I appreciated the dust and noise control also.

Thanks,

Alan

[Graybeard]

Alan,

My water table is 4" deep and I haven't built in my permanent support bars yet; I keep the water level about even with the surface of the steel I am cutting, so the real water level is about 3.5". I use a Poweremax 600 with finecut consumables, so the air pressure at the plate is about 70 psi. I don't have any automatic way of controlling the water level so it is sometimes slightly below or above my sheet steel (I fill it with a hose on cut days). My setup doesn't seem to splash or spray water and it seems to control the plasma dust, smoke and fumes. Some ventilation is still needed to get rid of a small amount of smoke or fumes coming off the upper surface of the steel. Also, note that I am cutting steel. I have been told that cutting aluminum above water can create a hazard because the aluminum plasma combines with the orygen in the water and releases hydrogen which is explosive (I don't cut aluminum and don't know if this advice is true.) I did have a rusting problem, but solved it by putting washing soda in the water. Also, when you have completed a cut, make sure the nozzle is raised above the water level.

[Knut]

HI Graybeard,

Thanks for the additional information on your water table. I will be cutting aluminum so sodium bicarbonate is out for a rust solution on steel.
Have heard of the explosion hazard cutting aluminum under water or with the sheet supported on water and will inquire on the regular plasma forum about the circulation fix for that.

I accidentally posted here in the first place, this is a machine project log.

Thanks,

Alan