I completed an introductory welding course at Conestoga College last year, and bought myself a small oxy-acetylene torch outfit. I figured my first real project should be a welding cart. I had my gas cylinders freestanding up against a wall, and that’s just not very safe. I try to cultivate a healthy fear of compressed gas cylinders. Especially cylinders containing oxygen and quasi-stable fuel gases. There are very good reasons for being afraid of gas cylinders.
I know you can buy a welding cart, and it would probably cost a lot less than I spent on materials alone. But if I did that, I wouldn’t have learned anything. I thought it would be useful to gain more experience before I embarked onto some of the projects that I learned welding for in the first place. And good thing I did, because one of the things I learned is that I’m a piss-poor welder.
Anyway, I drew up plans for the welding cart in Google Sketchup. You can see what it’s supposed to look like in the image above. I have also attached the actual Sketchup file and bill of materials, so you can build your own if you want.
I’m using it with the smallish LD and WQ size cylinders I bought from the local TSC store, on their cylinder exchange program. But I believe it will also accommodate the more familiar tall cylinders. I’m not using those tall cylinders now because they’re only available on an annual lease, and I doubt I’ll go through enough gases to justify the cost.
I made the base plate with a single piece of 3/16″ steel plate. And the tubing is all 1/8″ wall 1″ square-section tubing, which is probably overkill. The thing weighs a ton.
The toolbox was purchased from Home Hardware. It’s one of those standard red metal toolboxes, in the smaller 16″ size, to fit between the handles. The one at Home Hardware had a metal tray inside it. Canadian Tire’s version had a plastic tray. I felt metal was a better idea on a welding cart, in case something hot gets dropped in it. I made a shelf for the toolbox out of 1″ angle iron, corners mitred and welded. Holes were drilled to secure the toolbox to the cart.
The cylinder chains are attached by simple eye bolts, installed in holes drilled and tapped at the ends of those supports. I turned the outer eye bolts into hooks by cutting the eye open a bit.
The Sketchup drawings are a little vague about the position and dimensions of the axle-mounting parts. It’s going to depend on what wheels you’re able to scrounge up. I just made those details up on the fly. I salvaged the wheels from a cheap old dolly that was all bent up and broken.
Along the way, I made a couple additions that are not reflected in the Sketchup model. I added a piece of tubing on the side to hold filler rods. The tubing is open on top, and the bottom is capped. I drilled a tiny hole in the centre of the bottom, just in case it ever gets water in it, from rain or something. I also drilled and tapped holes to mount a little fire-extinguisher I kept nearby while I was welding. Better safe than sorry…
Here’s what the finished cart looks like with a coat of paint on it:
And here it is all loaded up:
Things I Learned
Sometimes welds look really good on the outside, but they’re actually brittle and weak. I was doing good strong welds in the welding class, but I guess I got sloppy at home. Sometimes I could break my welds just by hand. Some welds would break by themselves when other welds cooled down. The inside of the bad welds was porous and spongy. I think this was caused by too much oxygen. It’s hard to get the gas mix right. I’m still trying to get it.
When you weld something to the middle of a big steel plate, the plate will no longer be flat when you’re done. I actually anticipated that, and welded all the outside pieces first, thinking they’d hold the plate flat for me. But those welds broke when I welded the middle piece on. The welds were probably weak (see above), and the bending forces much greater than I had expected. So, cart is actually a bit wobbly.
Abrasive cut-off saws suck, especially at doing mitres. It’s really hard to get the thing set to exactly 45 degrees. And then all the effort is wasted anyway, because the abrasive blade is too flexible. The blade will bend and all the angles will be off. If you find you cut something just a little bit too long, using the cut-off saw to try to shave off a bit more is a nightmare. The blade bends and slips off to one side of the cut you’re trying to do. Better to just go at it with an angle-grinder and some patience.