When I bought my Miller Multimatic Welder I was really disappointed by the selection of carts available. Some were just too cheaply made, while many were just too small or low to the ground. Even when I looked at large or expensive carts I didn't see any that held multiple gas cylinders. The one from Miller looked flimsy and required an awkward secondary attachment for two cylinders. While I didn't yet have spool gun I wanted the ability to easily fit more than one cylinder on a cart that would also have room for a possible plasma cutter in the future and space is at a premium in my shop since I work on a very wide variety of projects.

I had two issues to overcome. Firstly, looking around online I found a video of someone who made a cart I kind of liked but he made it from scrap he had on hand and did not provide any parts list, dimensions, etc. Secondly, steel doesn't run cheap. To overcome this I designed my cart in Fusion 360 first. It was similar to the one I saw in that guy's video but I made some adjustments to the dimensions to fit my welder, have room on the bottom shelf for a possible plasma cutter later, and made room for two cylinders. Research online showed me that an S cylinder of 120cu.ft was just under 7.5" in diameter.

Dimensioning everything in Fusion 360 also helped me because the metal supplier has very long lengths and I have a short bed pickup. So even though I have a metal chop saw I wanted them to cut pieces that would be easy enough to fit my truck without dangerously hanging out the side or back. So I did some math and sent a cut list to my nearest metal supplier, list below.

WeldingCart_Schematic.pdf
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Supplies

Lengths I ordered from the supplier and later cut down to final sizes:

1in x 2in x 0.065in - Steel Rectangular Tube A500/A513 (Welded)

2x 5ft
1x 6ft
1x 3ft

1in x 1in x 0.065in - Steel Square Tube A500/A513 (Welded)

4x 4ft
2x 3ft
1x 6ft

1/2in x 1/2in x 0.065in - Steel Square Tube A500/A513 (Welded)

2x 7ft
1x 5ft
1x 4ft

1x set of 5in Heavy Duty Polyurethane Locking Caster Wheels

Optional for cylinder chain plate

1x 6x 17.5 sqft 16ga hot rolled sheet, ordered plasma cut slots per schematic

Step 1: Cuts

I started by using my chop saw with a steel cutting blade to make all the necessary cuts.

At this time I did not have a welding table, but I have a very flat concrete shop floor and some shims. I laid out each component as they would be assembled to check measurements. I also ordered just what I needed so I did not have spare room for errors which meant I didn't want to accidentally cut anything I didn't need on accident. I worked my way piece through piece crossing each one off on my schematic as I went.

Step 2: Shelf Assembly

I was using a MIG welding process and welded the bottom shelf/base together first.

Next, I assembled the middle and top shelves.

Step 3: Upright Assembly

I then Attached the uprights and shelves to the base, followed by the cross handle.

I used some of the scrap cut offs to cut and weld end caps on the tubes.

The back plasma cut plate with slots for cylinder retaining chains was added last.

Step 4: Drill Holes for Wheels

The caster wheels have galvanized wheel bases, which I've learned is not something you want to weld without careful consideration to the gasses it can give off. In either case, bolting them on instead makes it easier to replace if the wheels get beat up or need replaced later. So I drilled holes to bolt them on through the base of the cart in each corner.

Step 5:

Lastly, I painted the cart with a couple of coats of Rust-Oleum primer followed by the closest blue Rust-Oleum offered to Miller's blue color.

Step 6: Extras

I considered adding some hooks on the sides to hang my mask and hoses off of, but that's up to you.

Additionally, I later bought some expanded PVC sheeting and rubber edge trim strips to create a solid shelf across the rungs on top to support my welder and allow me to place markers and pliers on the shelf without falling through.