Water Circulator for watertable cutting of Aluminum?

[Knut]

Just how much flow and aeration is needed to keep hydrogen accumulation in a water table from building up to explosion levels?

Is it so touchy that the injected load of hydrogen needs to be addressed at the cut zone, or can the table just be flushed in bulk, exiting from one end and returning to the other?

Looks like a I need 4" depth just to have good water flow. Is it possible that hydrogen being so light, will rise between the slats and the cleansing flow should go parallel with the slats, across the table that is?

Thanks,

Alan

[Perp]

Unfortunately I have nothing of substance to add, but I really would like to know the answer to this. So I am subscribing to this thread just to make sure I do not miss the answer.
Also is it only in aluminum you have this gas problem or are there other materials to be careful with too.
If you change to plasma cutting with a bottled gas instead of Compressed air, do you still have this problem?

I know there are some very intelligent folks here who can bread this down for Knut (and Me too)

Thanks
Doug

[Graybeard]

I'd also like to know the answer before I start cutting aluminium on my table.

[x6xtyx9x]

This question needs to be brought up to the main screen again to see if there is a person in the forum with an answer. I never thought of this before and I am glad someone brought it up before I did something stupid because of something that is not obvious. If anyone knows the answer, please reply.

[taylors]

This is right out of the OMAX help menu.



N Warning!

Watch for hydrogen bubbles. If you cut a lot of aluminum, you will create aluminum powder from the removed material. This powder will accumulate at the bottom of the tank along with your garnet. The aluminum with then "rust" (oxidize), and turn into Aluminum Oxide, releasing Hydrogen gas in the process. This hydrogen gas forms bubbles in the tank, presenting a potential explosion hazard.

2Al +3H20 à Al2O3 + 3H2

If you cut a lot of aluminum on a regular basis, then this is something to take into consideration. Do not allow smoking near the machine, and keep the garnet levels in your tank low to prevent bubbles from accumulating within. Be especially careful when cutting materials that spark such as titanium.

No OMAX customer has ever reported a problem like described above, but it is known that on one occasion an abrasivejet that had been cutting a lot of aluminum caused a minor explosion when titanium was cut right afterwards. In this case, the explosion was strong enough to lift the sheet of material slightly out of the tank.

[massajamesb]

Just get an aluminum magnet


Seriously, other than some sort of screen, I am guessing you would have to dredge the tank pretty often to prevent any chance of it.

[Perp]

This may sound dumb, but could you use a pilot flame to burn off the hydrogen as it surfaced before it accumulated in lager quantities? Like they do at the land fill with the gasses produced under ground.

Also, the omax works through abrasion, meaning there are small particles of aluminum plate dispersed throughout the water tray, with a plasma I would imagine the material is burned/consumed quite a bit more, though I am not sure what exactly the slag in the bottom would consist of. Probably a lot of aluminum still in it too.


Doug