Upgrades and Mods - Lower Shelf and Pneumatic Water Level System

Hello all!

I just wanted to share a little upgrade project for my Crossfire that I just finished. I think these modifications make the machine much more useable in a large shop where it will get moved from time to time. Hopefully, this will help a few other folks as well!

First, I fabbed and installed an aluminum lower shelf to the specs shared by @bricklef. Having that finished, my first thought was that the Langmuir team should really consider offering these as an upgrade option when purchasing a Crossfire. Knowing what I know now, I would definitely buy one! It really makes moving the cutter and associated plasma generator around much easier. See the picture of that completed project below:

Next, I decided that I didn’t like the idea of draining my water table into a bucket by hand every time I was done cutting, so I added a 10-gallon tank and an air valve to push the fluid up from the tank into the water tray.

To do this, I added a pressure regulator mounted to the frame with a T-fitting before it to send air to the plasma cutter and the tank control system with only one quick disconnect fitting. Here’s a quick detail shot of that:

Then I ran a line from the pressure regulator to a spring-centering manual solenoid valve. I was in a bit of a hurry to get the project done, so I didn’t get fancy with the mounting. The only thing holding the valve to the frame is some 3M tape on the back of the valve and some zip ties, but it feels rock solid regardless. Here’s a picture of that valve:

Next, to prevent the drain fitting from holding any fluid in the tray, I welded a 3/4 NPT-F to 1/2 NPT-F reducer beneath the stock drain hole and put a 1/2" barb fitting into the 1/2 NPT threads pointing down. I don’t have a great picture of that, but it gives the advantage of not having anything above the bottom of the water tray preventing the fluid from draining completely. This location will serve as both the drain and the fill location for the completed system.

Then, I was worried that the fluid flowing from the tank to the table would jet straight up and make a huge mess. So, I welded a 3" long piece of the angle-aluminum, left over from making the shelf, above the drain hole as a deflector for when the fluid is flowing in. That looks like this:

I then ran a 1/2" hose from the drain on the table to one of the lower holes on a 10-gallon freshwater tank from an RV with the fill port capped. The upper hole receives the air pressure from the valve or vents the pressure from the tank, depending on the position of the valve. All plumbed up, the underside of the cutter looks like this:

As you can see, I’m just running the ground clamp for the plasma cutter on to the fitting I welded on to the table. What you can’t see is that I replaced the small sacrificial zinc anode that was a part of the stock drain with a 1 lb zinc ingot that just sits in a corner of the water table.

With the table filled, finished results look like this:

With the air pressure regulator set at 10 psi, pushing the handle on the valve up pressurizes the air above the fluid in the tank and pushes the fluid up the drain hose and into the water table pretty quickly. It takes a little over a minute to completely fill the water table. Check the linked video below for what that looks like:

Filling the Water Table

To empty the water table back into the tank, you just push the handle of the valve down to vent the air pressure in the tank and the water will fall from the table, through the drain hose, and back into the tank. That does take a little longer than I would like, so I make a little holder for the valve handle from some steel welding wire. With the holder holding the valve handle down, you can walk away from the table while it is draining, which takes about 5-10 minutes depending on how much water was in the table to begin with. The video below shows that process (excuse the clumbsy hands, it’s tough to hold a camera and do that at the same time!):

Draining the Water Table

All finished, I am really happy with the results and find it a ton easier to go from the machine sitting in the corner to having rolled it to an open area in the shop having started a program to cut. All in, I spent about $300 on the material for the shelf and all of the materials to make the water level system.

I hope you all find this helpful and make some improvements to the system that I haven’t thought of yet!


Awesome work! Thanks for sharing with the community.

Great job man! That’s awesome! The only thing I would be concerned about is eventually having to clean out the bottom of the water tank. Do you have any filtration system that you were planning to install? What type of fluid are you using?

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Instead of trying to lock the switch in the open vent (drain) position why not just put in a T somewhere along the line below the switch with a release valve?

You could accomplish the same thing as you are describing by just disconnecting the air supply and cracking the valve. If the valve was left open you would also add in a safety measure that would allow any pressure building up in the tank to escape. If you cut any aluminum the bits that get in the fluid can generate hydrogen as they react for hours /days after you cut stuff. It’s not a lot but in a sealed tank it could be an issue.

@Bleasdale: Thanks! I had thought about that as well and had planned to rivet a few layers of fine wire mesh over the ends of the diverter to prevent the large particles from falling into the tank. The smaller particles will probably slowly find their way to the tank, so I will likely have to drain and clean it every once in a while. Time will tell how much of a pain that will be…

I wonder if I could put some kind of trap in the drain line that would catch anything that gets past the mesh before it gets to the main tank? I’m thinking something like an oil catch can that you could just take the bottom off of when it gets too full of crud and dump it out… Thoughts?

@EdS: I had thought about using a multi-valve system, but I just liked the cleanliness of only having a single control valve to use. At this point, since I’m always in a hurry when I’m cleaning up, I usually leave that valve held open with the wire as the last bit of fluid is draining in to the tank when I’m putting it away and don’t let the valve close until the next morning when I come back to the shop. I’m pretty sure that should be long enough to prevent any off-gassing from causing any serious issues. but not positive. The only thing I worry about is leaving the valve held in that position overnight may cause some o-ring compression set over time and cause the valve to leak, but I’ll cross that bridge when I come to it.

Thanks for the feedback everyone!

Very impressive build!
What coolant are you running? Greencut?

Thanks! Yes, it’s the Greencut fluid. So far, I really like it. When I was using plain water, everything inside the water table got very rusty in a hurry. Ever since I added the Greencut and the water level system, no problems at all!

Where did you get that spring centered manual solenoid valve and how much was it, the only one I saw is like $130 on Amazon.

Also trying to think of a filter for the fluid. I do like the oil filter idea except I’m not sure how well one would work because of the viscosity of the greencut fluid compared to oil. What if you used a magnet or something on an empty oil filter canister that could catch steel particles. Obviously stainless and aluminum are not magnetic but I feel like it might be a better option than without any filter at all.

This is the valve I used. It’s $35 and ships for free, although it’s not the free 2-day shipping from Prime.

Temco Spring Return Valve - 5 Port, 4 Way, 3 Position

I like the magnetic catch idea, but you’re right, it wouldn’t help for stainless or aluminum. I wonder if you could make a swirl pot to hang under the table that had a drain in the center with a tortuous path between the inlet from the water table and the exit to the tank? That way, when the fluid drains into the swirl pot, it would catch all of the debris in the corners in the path that could be emptied separately, but it would still fill the water table normally. Hmmm…


Nice job. I am thinking of using a similar water tank. Now that you have had it for a bit have any issues come up? I have the greencut but haven’t tried it yet. Are there any issues with staining or buildup on the crossfire parts from it splashing on them? Hopefully it can just be wiped off an won’t leave any marks.

I was amazed how much and how fast it rusted with just water. Plasma must be an oxidizer.

I put a little water in right after assembly to run some test cuts. The fresh metal and slats got a bloom of orange velvet within minutes. The same for the stainless table as the water evaporated. I had to clean all that up before I filled the table with water and Pico quench guard G.

@wwmotorsports I’m curious how your water tank handles the air pressure. I just set up the same one but 15 gal. and when I let the air in it really bulges out and that’s with the valve barely cracked. It’s a little scary when I start to open it up with the warning that comes with it saying ‘do not pressurize it could explode’. My tube running the water up is similar in diameter to yours, which I think I will increase to increase fill and drain time hopefully. I think I’m going to add some angle iron or something around the tank to keep it from bulging.

Initially I put a strap around mine:

but then I added a plywood collar in two places along the sides. It does a good job keeping the tank from flexing. I only pressurize my tank to a few pounds so it’s not a problem.