Plasma water table users.

[Hood]

My table is only 40mm deep and catches everything fine.

You cut a lot of aluminium, you need to bear this in mind cutting on a water table in an enclosed space.
Might not be the best choice for you.

Aye, although as long as the water is getting agitated it is supposedly fine.

 

[doubleboost]

I had thought of that but wasn't sure how it would react to the arc, good to know it is ok.

I am not saying it is in any way safe but it works for me

 

[doubleboost]

Are you using the xtreme tray or did you build your own?

xtreme tray

 

[Brad93]

Our table is about 100mm deep. Catches all the dross and very little fume.

 

[Bladevane]

I use sodium carbonate in the water tray. 1g per 10 litres to get the Ph to 11 ( I think from memory). I’m sure I read that a high water level, up to workpiece level, can eat consumables. Mine is the Xtreme tray. I’ve added downdraught which works brilliantly and keeps the workshop free of dust and fume.

 

[Hood]

I use sodium carbonate in the water tray. 1g per 10 litres to get the Ph to 11 ( I think from memory). I’m sure I read that a high water level, up to workpiece level, can eat consumables. Mine is the Xtreme tray. I’ve added downdraught which works brilliantly and keeps the workshop free of dust and fume.

How does the downdraught work? Is it at the same time as the water or do you use one or the other?

On my current table I made it downdraught and it works really well and the only reason I was thinking of water on this was that the tray will be Aluminium and I thought that it may get damaged from the plasma dust/metal/spray and thus that water would be a better option.

I may just go with a stainless tray instead and stick with downdraght, that is if I even go ahead with the new build

 

[Bladevane]

My trough is full of water all the time to a depth of about 30 mm. It is still around 150 mm below the under side of the material. I boxed in 3 sides of the table with hardboard then manufactured a plenum on the 4th side with a 6" diameter outlet connected via metallic flexible hosing to a 1.5HP 3000 rpm centrifugal fan. I cover the area around the workpiece with heat resistant polymer coated cloth. This creates a slight negative pressure under the workpiece which seems to extract virtually all the fume and dust. I don't think the water does much to prevent fume and dust but it does provide a quench for cut outs and downward spray.

 

[Hood]

My trough is full of water all the time to a depth of about 30 mm. It is still around 150 mm below the under side of the material. I boxed in 3 sides of the table with hardboard then manufactured a plenum on the 4th side with a 6" diameter outlet connected via metallic flexible hosing to a 1.5HP 3000 rpm centrifugal fan. I cover the area around the workpiece with heat resistant polymer coated cloth. This creates a slight negative pressure under the workpiece which seems to extract virtually all the fume and dust. I don't think the water does much to prevent fume and dust but it does provide a quench for cut outs and downward spray.

Ok, that is also doable for me although I have heard if the water is good at fume/dust suppression as well but that maybe needs it to be fairly close to the metal underside.

 

[Bladevane]

I wonder if it's too close to the underside whether the air jet creates more vapour in the air than it suppresses?

 

[Hood]

No idea, never had a water table so if I go down that route I suppose experimenting will be needed to find out what is best.

 

[henry Kadzielski]

The water is supposed to virtually stop all fume, but it is messy. I have built my table as downdraught and with the extension will still be downdraught. A lot of water will be required to fill a tray 2m by 6m. The new design in the table has a duct formed to chanel the fume to a collector which will have a 3 phase fan 560mm in diameter connected. The table is also seperated into 3 segments which will also be able to be isolated. Any way gantry (Y axis) drawings done, 20mm 5083 plate cut, tenders out for the machining. Should get replies back this week and get the gantry welded up

 

[Revs1972]

I have noticed on mine that it cuts better when the water level is higher (swiftcut)
I haven’t changed the water yet ( been over a year) , but I have cleaned out the table ( incredible how much dross and particles are captured). I used the original 5 litre of additive when it was set up, and used their tablets each week until they ran out . Now use fish pond tablets as much cheaper. I did pick out some parts from very early on in its use , so had probably been hiding in there for 9 months + and they were in perfect condition, so the rust inhibitors do work.
Speaking to an independent engineer , he says one of his customers just uses plain water in his, but religiously changes it once a week whether it needs it or not.

The biggest PITA is when parts drop down between the slats and you have to fish them out. I only have a slat in every other slot ( how it comes) , so will put a fresh slag in each slot when it gets serviced ( which was arranged to be done , just as this virus kicked off)

I read somewhere about the build up of explosive gasses when cutting aluminium, but it only sounded like it was an issue if your sheet covered the whole bed, and you were cutting shed loads of parts out, without giving them a chance to disperse.

 

[Bladevane]

Can you provide details of the fish pond tablets please?

 

[Brad93]

I have noticed on mine that it cuts better when the water level is higher (swiftcut)
I haven’t changed the water yet ( been over a year) , but I have cleaned out the table ( incredible how much dross and particles are captured). I used the original 5 litre of additive when it was set up, and used their tablets each week until they ran out . Now use fish pond tablets as much cheaper. I did pick out some parts from very early on in its use , so had probably been hiding in there for 9 months + and they were in perfect condition, so the rust inhibitors do work.
Speaking to an independent engineer , he says one of his customers just uses plain water in his, but religiously changes it once a week whether it needs it or not.

The biggest PITA is when parts drop down between the slats and you have to fish them out. I only have a slat in every other slot ( how it comes) , so will put a fresh slag in each slot when it gets serviced ( which was arranged to be done , just as this virus kicked off)

I read somewhere about the build up of explosive gasses when cutting aluminium, but it only sounded like it was an issue if your sheet covered the whole bed, and you were cutting shed loads of parts out, without giving them a chance to disperse.

Ours also gives less dross if the water is hogher

 

[Revs1972]

Can you provide details of the fish pond tablets please?

I can look when I’m next down at the unit (not sure when that’s going to be ).
I didn’t get them myself , but pretty sure they aren’t anything special. Probably not as potent as the swiftcut branded ones ( they are marked as do not use in fishponds)

 

[Revs1972]

Does anyone use Greencut fluid in their water table ? Apart from looking cool, are there any advantages as it’s pretty pricey

 

[Hood]

Some info on Aluminium cutting with a water table from a few sources.

https://www.esabna.com/us/en/education/blog/can-you-plasma-cut-aluminum-on-a-water-table.cfm


https://www.hypertherm.com/support/...ma-cut-aluminum-on-a-water-table/?region=EMEA


https://gizmoplans.com/what-are-the-hazards-of-cutting-aluminum-with-plasma/

 

[Andbarbred]

I have noticed on mine that it cuts better when the water level is higher (swiftcut)
I haven’t changed the water yet ( been over a year) , but I have cleaned out the table ( incredible how much dross and particles are captured). I used the original 5 litre of additive when it was set up, and used their tablets each week until they ran out . Now use fish pond tablets as much cheaper. I did pick out some parts from very early on in its use , so had probably been hiding in there for 9 months + and they were in perfect condition, so the rust inhibitors do work.
Speaking to an independent engineer , he says one of his customers just uses plain water in his, but religiously changes it once a week whether it needs it or not.

The biggest PITA is when parts drop down between the slats and you have to fish them out. I only have a slat in every other slot ( how it comes) , so will put a fresh slag in each slot when it gets serviced ( which was arranged to be done , just as this virus kicked off)

I read somewhere about the build up of explosive gasses when cutting aluminium, but it only sounded like it was an issue if your sheet covered the whole bed, and you were cutting shed loads of parts out, without giving them a chance to disperse.

My swiftcut will evaporate the water off in a couple of weeks, how do you make it last a yearr?

 

[Revs1972]

My swiftcut will evaporate the water off in a couple of weeks, how do you make it last a yearr?

Top up with water when it gets lower. Its not used to its full potential so evaporation is fairly slow. Topped it up 4 times. Although the time I did remove the dross and dust it went down quite significantly.
Now , I don't know how true this is, but I have read it is the water that is evaporating, and not the anti rust fluid, so topping up shouldn't dilute it

 

[Hood]

....
Now , I don't know how true this is, but I have read it is the water that is evaporating, and not the anti rust fluid, so topping up shouldn't dilute it

That is certainly the case with coolant in lathes, milling machines etc, well CNC anyway where it is not being thrown on walls and floor.
Most of the time it is just water that needs topped up but after a while you need to add some soluble oil as well.