How to Build a Welding Cart

(or "mig-cart", "plasma cart", hors derve tray, whatever)

     unfinished cart                                completed cart

Welding websites carry hundreds of pictures of various designs of carts that folks have created, ranging from elaborate works of art to some that consist of pieces of discarded scrap welded into a larger piece of (s)crap.  For most hobbyists, the cart to carry your new welder will be the first project you undertake.  The problem with many of these websites is that few provide you with step-by-step instructions, measurements, plans or materials lists for which many beginners are seeking. This is why this website is here- to help you with your first project!

This cart will take only a few hours to easily construct (not counting priming and painting) and when completed will be sturdy, highly functional and attractive.  I designed it for my own purposes (which are two 80 cubic-foot tanks of gas, a mig welder and a buzz-box arc welder), but you can easily adapt it to your own machines or for storing and carrying whatever you want.  For those that have a Lincoln AC225 (seems like most of us do) and a Mig-welder (or plasma-cutter), the design is perfect, with the big heavy one underneath and the smaller (MigPak 140) box on top.  The total cost, including steel and paint was under $40 (compare that to a commercially available cart which will be well over $100) plus you have the fun and satisfaction of doing it yourself.  After all, if you didn't love doing this stuff, why own a welder???

For those that are already beyond the beginner stage, you're probably already bored so enjoy the pics of the cart and thanks for dropping by.  For those beginners that will use the instructions, read on and enjoy- if you have any questions, email me and I'd be glad to help you out!  If these helped you, I'd be pleased to know about it.

Oh, and the liability stuff because that's where we've gotten to:  There are many dangers involved with welding and power tools- read all manuals first and use all safety equipment including eye protection.  The author assumes no liability for any mishap, loss or negative consequence resulting from these instructions and makes no assertion of the validity of any information found herein.  You follow these at your own risk.


Now on to the fun- I hope you enjoy this project as much as I did!



Dave Jewers

Maple Ridge, British Columbia




- Welder (preferably MIG but an Arc-welder is fine too)

- Angle Grinder

- Marking tool (sharpie, pencil, etc)

- Level

- Framing Square or Combination Square

- Clamps (a C-Clamp and a bar clamp or Quick-Grip type)

- Saw (Jig saw, hand saw or Table saw)



- #10-32 NF Tap   (only needed if tank straps are screwed and not welded)

- Drill (only needed if tank straps are screwed and not welded)

- 5/32" and 3/32" drill bits (only needed if tank straps are screwed and not welded)

- Tubing bender (only if curved front handle is desired)

- Hack saw, chop-saw or plasma-cutter (if components are not cut for you by your steel-supplier)

- 90 degree angle clamps (framing clamp; really helps with welding the frame for the base)

- Bench vise (easier than holding the frame yourself to keep the welds in an upright position)

- Quick-Clamps (they are great for everything- get a couple anyway- you'll use them soon and often)

















Nomenclature used to describe components



   The steel for this project cost me just over $30 at a metal supply store.  Pretty cheap when you consider that a comparable commercially-available mig-cart will run you upwards of $100-150.  The owner of my local shop (MetalTropolis) even cut the pieces for me- which saves a lot of work.  Here's what you'll need:

- (2)  2x2" square tubing (thin walled apx 1.5 mm), 60.6 cm in length (apx. 23 7/8")  (base, long side)

- (2)  2x2" square tubing, (thin walled apx 1.5 mm), 42.2 cm in length (apx 17")  (base, short side)

- (2)  2x2" square tubing, (thin walled apx 1.5 mm), 70 cm in length (apx. 27 1/2")  (upright supports)

- (2)  1 1/2" (3.8 cm) angle iron (upper deck rails/arms), each=49 cm in length (apx 19 1/3")

- (4)  wheels (2 swiveling, 2 non swiveling)

- (1)  3/8" angle iron, apx. 35 cm (upper deck rails support bar)  (Note: purchase an extra inch and cut to size to properly space your setup)

- (2)  3/8" angle iron, each apx. 10 cm (apx 4") (rear deck supports)

- (1)  rear-deck material (plywood, mdf, plate-steel, whatever)

- (1)  top-deck material (plywood, mdf, plate-steel, diamond-plate, whatever)

- (2)  nylon straps with cam-lever (tank holder)

- (1)  length of steel tubing (or EMT-conduit) apx. 3 feet

- (1)  length of 2x3" or 2x4" stud (to properly space uprights)

- (2)  1" to 2" round steel tubing (each apx. 1.5-2" in length) (wire support brackets)



    Lay the four steel base components on a smooth, level floor and fit them into the proper shape, as they will be when completed.  Note that the ends of the longer pieces weld onto the sides of the shorter pieces, not vice-versa.  You could change this if you wanted it slightly wider and less long but mine was designed specifically for the width of the AC225 and the length for a Mig-welder on top with room for 80 cu ft bottles behind.

   Once layed out, ensure all sides are square, level and fit evenly.  Now, with your angle grinder, remove any mill-scale or corrosion down to the clean, shiny metal- this will facilitate much better welds.  You may clean simply the areas that are going to be welded or you may clean-up the entire assembly in preparation for better priming/painting, the choice is yours.  Keep in mind that doing it as this stage is far easier than after you've welded it as many areas will be inaccessible or hard to get at with your grinder.  I recommend you clean it all.





  The 4 base components layed out

If you have an angle clamp (the kind frequently used by woodworkers when holding/gluing two pieces of wood together in a 90 degree angle) it will make an excellent job of holding the corners square while you weld.  If not, you could also use a small block of wood on the inside angle and two clamps to hold it in place.

Once the pieces are locked in tight where you want them to be (hold your framing square on the outside to ensure they are squarely 90 degrees) and perfectly flat on the floor- then it's time to weld the base.



     90 degree angle clamp is a big help



Because we're using thin-walled tubing, be very careful to turn the power WAY down so you don't vaporize the steel!  On most mig welders, the lowest wire-feed setting and probably the second-lowest voltage setting will suffice;  with your arc-welder, possibly no more than 40-50 amps.  Test it on a piece of scrap first to check for sufficient penetration without burn-through.  Make sure to weld the inside of each corner and at intersecting joints.  If you also weld the joints on the bottom side of the base, keep in mind that you will later need to grind these welds flush to allow the wheels to sit flat on the base.   I don't need to tell you what to do at this stage- after setting your heat correctly, have fun and lay some beads!



   Now that the base is fully welded, you can begin to construct the uprights, which will support your mig welder (or plasma cutter, toolbox, neighbour's cat, whatever is going on top).  Generally, the upper deck will be narrower than the base, and keeping the weight more "inboard" makes for a less tippy platform, particularly if you don't plan to have a lot of weight on the bottom.  The main consideration in the placing of the uprights is leaving sufficient space on the rear deck for your cylinders.  In the photo to the left, I placed an 80 cu ft Argon tank on the base to ensure that the placement of the uprights still left sufficient room for the cylinders without overhanging at the rear end.  If your plan is to have larger (or smaller) cylinders, determine where you want the uprights placed and mark their positions on the base.  To avoid a crooked placement of the uprights, measure the distance to the end of each side of the base to ensure that each is the same.






Placement of uprights must accommodate cylinder on rear deck










Side view, ensuring cylinder fits onto rear deck.


Now that we've determined where we want the uprights, it's important to ensure that they remain equi-distant from one another (the distance between the two uprights is the same at the top as the bottom).  The heat of the welding process can easily warp or distort metal, plus even small differences in the completed spacing will be easily noticeable, cause weakness in the upper deck and in general is a sign of shoddy work.

To ensure the uprights stay perfectly straight, you will need to carefully measure the distance between the two uprights at the bottom.  To do this, securely clamp an upright in the position in which it will be welded and measure the inside spacing to the opposite upright.  Then cut two pieces of 2x4" lumber to this exact inside measurement.  Wedge one piece into the bottom of the assembly (if you measured precisely, you will need to use a small hammer to gently tap it into place).  This will hold the opposite (unclamped) upright tightly against the other side of the base.  Now, place your second piece of 2x4" lumber between the top of the uprights and clamp it in place with a bar-clamp or Quick-Grip as shown in the photo.  This ensures that both uprights will not move and ensures that both will be perfectly vertical.  As a last check, use your framing square to check that each upright is 90 degrees to horizontal in all directions.   

Now it's time again to start welding.  While you could hold the frame, it's far easier and will result in better welds if you clamp the whole assembly into a large bench vise, repositioning as necessary to always keep the surfaces to be welded facing upward (unless of course, you want to practice your out-of-position welds).



    First, if your weld beads on the underside of the base-frame have not already been ground flush, do it now so the wheels will have a smooth flat area to be attached. 

On my cart, the wheels have been attached by simply "tacking" them with the welder in about 4-6 places.  This is very easy and entirely sufficient to hold them forever.  In the past, I've attached the wheels by drilling the wheel's steel bracket, then tapping (cutting threads) in the steel tubing.  This lets you attach the wheels with screws/bolts. The advantage of this is that it allows you to easily remove the wheels to adjust the height or to replace them should one ever become defective.  The drawback, and it's a big one- is that it's a LOT more work.  If you bought decent wheels, they will last a lifetime, so it's far easier to weld them on and if you ever DO need to replace one, 3 minutes with an angle grinder will remove them.  (Don't forget to first "clean-up" the steel brackets and tubing at the attachment points with your grinder to ensure quality welds).




Now that the uprights are securely attached, you can attach the two pieces of angle iron that will support the upper deck.  The height I chose was determined by placing whatever is going on the lower deck (in my case, a Lincoln AC225) onto the frame to determine how much clearance was required.  Keep in mind that once completed, the welder will occasionally need to be taken out and placed back in there so don't make the upper deck flush with the welder's top which would make removal very difficult.  Leave at least an inch. 

Use clamps to hold the upper-deck supports securely in place on the uprights.  With a bubble-level (or better yet, a couple of them), ensure that the upper-deck supports are level in each direction (your floor may not be precisely level, so as long as the top is level with the lower deck and lower deck to the floor, you're good).

When you are satisfied with their placements, crank the clamps tight and fire up the welder!




Leveling the upper-deck supports



What is a welding cart without a place to hang the dozens of feet of electrical cables attached to them?  Making a hanger to accomodate these cables is simple- weld two pieces of 1 inch diameter steel tubing to the side of each upper-deck support (Note that it need not be one-inch tubing- if you have smaller or larger lying around as scrap, that's fine too).  

If you want to move the cable hangers, fine- just keep in mind that too far rearward (and lower on the upright) may conflict with both the nylon cams (added later) and the tanks on the rear deck.  I wanted them as close to the rear uprights as possible to keep the wires out of the way and to position the centre of gravity closer to the cart's centre (to keep it steady by balancing the weight).






Cable hanger mounts attached to upper deck supports



Whatever you want to add to the outside of the cable hangers to keep the cables on the cart is your choice- I've used some old wrenches cut into a X-shape and welded to each side- but feel free to be imaginative and express your individuality with whatever suits you.  Perhaps a wood carving, maybe some other tool like hammers, a couple of pipes that are neatly notched/fishmouthed, hood ornament from a car, whatever...  This is your chance for an individual touch that makes it unique.







Wrenches welded to cable hangers



The supports for the rear deck (gas cylinder deck) depend on the material you have chosen to use for the deck.  I chose 3/4" plywood because it is easily shaped and was lying around my shop so the price was right.  The thickness of whatever you choose for your deck determines where you place the supports that will hold it up.  In the photo on the left, I'm placing the angle iron (cut to fit into the gap between the rearmost part of the base-frame and the upright.  In the right photo, you can see that I'm holding a piece of my deck material on the support and positioning the support so that my deck will be flush with the base frame.  Once you have determined the proper height, clamp the piece of angle-iron in place and weld it.  While this isn't a welding tutorial, I will remind you that on pieces like this, it's always a good idea to make a couple of tack-welds on each end, then in the centre to avoid the metal warping outward as you progress along with your bead.

After the supports have been installed, you can cut your rear deck to size and test-fit it. My rear deck measured 34.2cm x 13.7cm however I recommend measuring it yourself in case you opted to relocate (or inadvertently relocated) the uprights.

Repeat this for the other side of the rear-deck and then we'll move on to the upper deck.



Making the deck flush with the base



Positioning the rear-deck support

By now, you will have noticed that the upper deck arms are not completely secure (they will move or jiggle a bit if bumped).  This is corrected in one of two ways:  if you are planning on bolting (or welding) your upper deck to the supports, you may skip this step as the secured upper deck will suffice to secure the arms.  If you are undecided about the upper deck or plan to change it later, the best method is to simply weld a piece of angle iron (or suitable rigid scrap) between the two arms.  This way, regardless of whether your "convertible" top deck is installed or not, the arms will be very secure.

Before welding, it is important to take a measurement of the distance between the arms at the rear (where they are welded to the uprights) and ensure that the fronts of these arms are the same distance.  Placing a clamp on the ends of the arms (similar to what we did previously) will help ensure they don't move while you weld it up.  Once the piece of metal is welded between the two uprights, were good to go.

A further note:  I designed the upper deck to carry the weight of my mig-welder- if you are placing something particularly heavy on top (or a lot of heavy objects) you will want to weld some additional supports on the front of your cart to bear the extra weight. 

On the left is a photo I took of a cardboard mock-up of the mig-welder.  This allowed me to properly size and determine the height of the upper deck support arms and determine if I wanted to have the arms (and welder) on an angle.  Always keep some cardboard on hand and don't be afraid when doing your own projects to construct a similar model to visualize ahead.  A few minutes then can save a LOT of grinding and re-welding time later on when you discover the mistake you could have easily avoided.

Imported "Rincoln Erectric" welder



I made my pull-handle out of 1/2" EMT tubing (conduit) that I had lying around after a recent electrical project.  It is readily available at any home improvement store in the electrical aisle.  I bent mine using a tubing bender, however many people don't have a bender.  If that includes you, you can still make a handle by cutting the tubing in a series of angled cuts.  Either a couple of 45 degree angles or a series of smaller angles will make the 90 degree curve (and you'll have more fun welding them together).

It would be appropriate here to remind you that most EMT tubing is galvanized (that shiny, irregular/patchy coating applied to the outside of steel to prevent rust).  The fumes created by the burning zinc coating are highly toxic to humans.  If you are going to weld on anything galvanized, grind the coating off first and do so in a well-ventilated area.  Many weldors suffer life-long lung ailments because they didn't take these precautions with galvanized coatings.


If you're skilled at bending, you can make both bends in a single piece of tubing.  If you're not skilled, bend nineties in two separate pieces, then cut them to be an equal distance from the cart, then join them together by welding the straight piece in between.

Note that this stuff is super-thin and great care will have to be taken not to burn-through while welding.  You may find it is more effective to do multiple spot-welds (no more than a quick, half-second bzzzt and then stop) all the way around, to avoid burn-through.

Once the tubing is in the shape you want, it can be welded to the front of your cart.  To do this, I chose to weld a small square piece of steel into the angle between each of the two front ends of the angle iron that comprises the upper deck supports.  What this did was create a flat, vertical surface upon which I could weld my front handle.  Another (and probably more attractive option) is to attach the front handle underneath these pieces of angle iron with some additional bending.  Or the easiest method, simply welding the tubing flat against the underside of the angle-iron.  Determine how nice you want it to look and make your own choice.

Bending the EMT-conduit into a 90 degree angle



I chose to use a couple of the nylon-straps with metal cam-buckles (not sure of their correct name) because they're strong, work great and will last forever.  You can pick these up at any hardware store, usually in red, blue or black.  You can see from the photos that mine are blue- simply because I found a couple lying around my shop that were intended for something else long ago but never used and were still in the package.  I would have preferred red to match everything else (as my style consultant later reminded me) but once again, the price was right (I AM Scottish, after all).

To attach the straps, you have your choice- the brackets for these are usually steel so you can weld them to the upright, or you can do it the way I recommend: bolt them on.  While going this route of attaching them with fasteners (screws or bolts) certainly takes a lot more initial work, you have the ability to later remove them very quickly (for example, to replace a damaged one).

To attach them, we first need to select a vertical location on the upright- mine were located as a compromise between being high on the tank yet still relatively close to the halfway point between the two decks (I think the style consultant said something about Feng-shui). 

With a centre punch (or nail if you're that poor), punch a small indentation in the metal at the point you want the cam's securement bolt.  Note that if your particular strap doesn't have a hole on the backside, you will have to create one.  Drill the hole, first with a small bit- say a 3/32", then use the bit that is sized appropriately for the tap you are going to use.  I recommend a very fine thread, since the square tubing is thin walled and we want more threads gripping the screw (ideally, we would weld a small square of steel to the side and also drill through and tap this (for added threads) however this should be sufficient unless someone wants to reef on it with considerable force.

I chose a #10 screw with a 32NF thread.   This requires a #10-32NF tap which will require us to enlarge the previously drilled hole with a 5/32" drill bit.  Once the hole is drilled, tap the hole and install the screw (without cam/strap).

Even if you're not planning on having a second gas cylinder, repeat the process on the other side and install the screw.  One day you may decide to get another cylinder or who knows- maybe your grandson will inhert this cart and need to carry a tank of both Argon and C25.

Tank securement strap installed




As mentioned previously, for best results all metal must be cleaned up prior to this stage.  By cleaned-up, I mean at least the rough mill-scale, rust and all welding-spatter and poorly-placed beads ground off;  but more preferably- all metal ground or sanded down to bare, shiny metal.  If you have a sand-blasting setup- so much the better.  Don't forget to tape up any decorative metalwork that you used for your cable-holders.  

Most paints require that the steel first be primed prior to painting.  Even those that indicate they don't require primer cause me some suspicion- so I always prime first.  My personal choice is Tremclad (both for the primer and paint) because I've been using them for decades and am very satisfied.  Again, it's your choice- but I can say for sure that for this project, you will be pleased with the results that you get from Tremclad.  You can go with two coats of primer if you want, however if you're like me (a four-year old inside), you won't be able to wait any longer to get the paint on it and see how it's going to look- and that's okay, one coat of primer will suffice.  Let it dry overnight (unless your brand's directions say otherwise) and then we're on to painting.

I chose the colour (black) because the equipment the cart was going to carry is red and black (but I didn't want too much red, which the welders predominantly are) so black it became.  Oh, I should also mention that prior to making this decision, I consulted with my significant-other/fashion consultant who confirmed that the colour should be black to match the tools.  Men, before you break out that can of flourescent metallic-pink paint which you are SURE will look great, check with a woman.  Trust me on this- we just don't know style like they do.

When applying the paint (just like the primer) always use very light coats- applying too much paint causes drips and runs which looks like crap when it dries.  Like most things in life, if it takes longer, it usually gives better results.  Take your time and do it right.  Also, make sure to do it in a well ventilated area (while you might enjoy the brief high you get from the toluene, it does kill brain cells).  And if you're using your driveway, throw some newspapers down (in an area larger than you think you need) to avoid marking it up and the inevitable dirty looks/abuse you'll get later when your style consultant discovers it!

Tremclad's instructions indicate that it must dry overnight between coats.  Unless you have the special equipment/atmosphere to speed it up, don't rush it and wait at least 8 hours before reapplying.  Once it is dry, some like to very lightly sand the coat of paint (which I believe the instructions specify)- this smoothes out any roughness and makes the next coat stick better.  I didn't and have never had a problem- your choice.  Once again, if you're four years old like me, you'll be highly tempted to get your equipment onto the cart but wait until the final coat dries.


A second coat of paint (or third if you're so inclined and can wait that long), reinstall your upper and lower decks and the tank securement cams/straps and your welding cart is complete!



Your comments are appreciated!