I love TIG welding more than anything in the world, and I intentionally design my pieces to involve lots and lots of welds. This 31-sided stainless steel vase is a great example: Each edge is welded, not folded. It’s a delicious challenge for anyone who wants to practice their precision TIG welding!

I designed the vase in SketchUp, and generated a cut layout with 123D Make. I cut each face out of stainless steel sheet with a hydraulic shear, TIG welded the faces together, and sanded down the entire piece with an angle grinder. This process can be used to create any hollow, geometric form out of sheet metal – use your imagination and create your own vessel!

In case you saw my last Instructable, the TIG-Welded Steel Bowl, here are some of the techniques I’ve added or improved since then:

Using 123D Make to create a cut layout instead of manually redrawing each face shape in Illustrator (this saved me at least two hours’ worth of work!)
Pulse-welding to ensure a smoother, more even weld with less warping
Testing to see if the vase is watertight and filling any holes
Using a hydraulic sheer to cut out each face instead of waterjet cutting (I wouldn’t call this an improvement, per se, but it’s a great option if waterjet cutting isn't available)

Step 1: Materials, Tools, & Safety Gear

Materials:

16-gauge stainless sheet steel (you can use any sheet metal that you feel comfortable welding)
.035” and .0625” stainless steel TIG filler rods (match the filler rod metal to your sheet metal)
1/16th” tungsten electrodes, 2% lanthanated
Printer paper
Water for testing for leaks

Tools:

TIG welder
Tungsten grinder
Hydraulic shear (or other tool that can cut sheet metal)
Variable-speed angle grinder
40-, 80-, and 120-grit flapwheel discs for angle grinder
Scotch-Brite disc and adaptor for angle grinder
Computer with SketchUp and 123D Make installed (both are free to download)
Printer
Scissors
Glue stick or double-sided tape
Permanent marker

Safety Gear:

Welding hood
TIG welding gloves
Safety glasses
Earmuffs or earplugs
Respirator with particulate filters
Natural-fiber long sleeves and long pants

Step 2: Create 3D Model in SketchUp

I knew I wanted to make a tall, narrow vase with symmetrical facets. But since I’m still learning how to use CAD software to create 3D models, I struggled to create the type of shape that I was envisioning in my mind. After playing around with a few different strategies, I figured out that I could import and modify an existing polyhedron model instead of building one from scratch.

I opened up Sketch-Up and searched through their 3D Warehouse to see what kinds of geometric solids were available for download. I searched polyhedrons, spheres, and dodecahedrons, and eventually found a faceted sphere that I liked. I imported the model into my worksheet, modified it by adjusting the proportions and scale, and removed the top face in order to create a hollow vessel. I didn’t bother to account for sheet metal thickness in my model because I’ve found that I can still get a pretty tight fit regardless.

I’m excited to eventually learn proper parametric 3D modeling in order to make much more complex geometric forms in the future. But since I was on a tight deadline for this project, modifying an existing model worked really well!

Step 3: Generate Cut Layout With 123D Make

Once I had created a 3D model of my vase in SketchUp, the next step was to “unfold” the model in 123D Make to get the cut layout.

Since 123D Make requires that objects to be imported as either OBJ or STL files, I installed a free SketchUp extension called SketchUp STL that allowed me to export the vase model from SketchUp as an STL file. I opened up the STL in 123D Make, double checked that the object dimensions were exactly as I wanted, and selected "Folded Panels" for the construction technique. Since I wanted to print out the template on printer paper, I selected "Letter" under the Manufacturing Settings menu.

I selected the option to "Split Panels," which separated out each individual face. For this project, I chose to separate the faces and weld them together instead of bending one or two larger, connected shapes. I made this decision because the brake in my shop doesn’t have a particularly tight bend radius, and I wanted sharp edges for my vase. Also, I’ll take any excuse to TIG weld, so doubling or tripling the number of welds didn’t sound like such a bad thing to me! If you decide to make a piece like this, it might make sense for you keep the faces connected and bend them -- do some tests with your brake to see if this is a viable option.

I clicked "Get Plans" to see the cut layout, exported it as a PDF, and then printed it out. I also printed one extra page, just to give myself some extra shapes to practice with.

Step 4: Cut Sheet Steel With Hydraulic Shear

I took the printout and cut out each shape with a pair of scissors, leaving a small margin on all sides. I used double-stick tape to affix each piece to the stainless steel sheet in a grid layout, thinking ahead to the order in which I’d be making cuts. My cutting approach was to first cut out each row, then cut free each shape, then trim down any remaining sides.

(Tip: I would not recommend making a template and tracing it multiple times with a pen – I tried this initially, and it resulted in very imprecise, asymmetrical shapes that didn’t quite fit together. Taping a printout to the steel worked much better!)

Before you start cutting with the hydraulic shear, do some practice cuts on scrap metal first to make sure you can consistently cut right on the line. With practice, I eventually got a feel for how to compensate for the shear’s slight idiosyncrasies.

For projects like this in the past, I’ve actually paid to have the pieces waterjet cut – it’s incredibly precise and clean, but expensive to outsource. Since this wasn’t a paid job, I decided to save the money and do the cutting myself. It was tedious making 100+ individual cuts, and it was definitely less precise than waterjet cutting, but I needed the pieces quickly and cheaply. Glad to know that this is a solid option when waterjet cutting isn’t accessible.

Step 5: Set Up TIG Welder

Since I used 16-gauge stainless steel sheet for this project, I used 1/16th” lanthanated tungsten electrodes and stainless steel filler rod in both .035” and .0625” thicknesses. I sharpened a handful of tungstens, opened the gas, and set the machine to 80 amps and six-second postflow.

Make sure to wear a welding hood, welding gloves, and natural-fiber (or leather) long sleeves and long pants when TIG welding.

Step 6: Flash-Tack Edges Together

As you can see from the time-lapse video above, my strategy for assembling the vase was to flash-tack all the pieces together, just using my hands to hold the pieces -- no clamps or vice grips! (A flash-tack is a quick, powerful spot weld.) I didn’t worry about getting a precise angle because the tack welds were flexible enough to bend into the correct angle when needed.

I start tacking at the bottom of the piece, making a single tack weld in the middle of each edge. As I added each new piece in, it became obvious whether I needed to force any joints open or closed a bit in order to fit the new piece in. In the video, you’ll see me manually adjusting the angles in between tack welds.

This is when it pays to have precisely-cut pieces: The more precise the pieces, the tighter the fit!

Step 7: Tack Weld Each Vertex With Filler Rod

Once the entire form was assembled, I went back to do another round of tack welds on each vertex. The goal was to get all of the corners at each vertex to melt together into one little pool. If the corners didn’t quite meet one another perfectly, I added a dab of filler rod to make a bridge and eventually a pool that joined all of the corners together. Don’t forget to fill the corners along the opening of the vase as well.

Tacking the corners will make your life much easier when it comes time to weld all the edges: It’ll keep you from accidentally blowing holes in the sheet metal as you approach the corners.

Step 8: Pulse Weld All Edges

I learned how to pulse weld for this project, and it changed my life. Pulse welding, as the name suggests, is when the amperage “pulses” on and off as you weld. You can set the frequency and duration of pulses, and the maximum and minimum amperage. I set my machine to pulse two times per second, on for 50% of the time, with a max of 75 amps and a min of (I think) 30 amps. I did a few experiments on scrap metal and played around with different settings to see which worked best.

Once I had gotten a feel for how pulsing worked, I ran a quick pulse weld along each edge of the vase that had a tight fit (I skipped edges that had large gaps). I just did fusion welds – no filler rod. To reduce the risk of warping, I’d weld half an edge, then pause and work on a weld on the other side of the vase before coming back to finish the first weld.

Pulsing allowed me to create prettier, more even “fish scales” than I'd normally be able to make. And because the power was pulsing on and off, it meant less heat – and therefore less warping – in the piece. Amazing! Can’t believe it took me this long to get around to trying out pulse welding!

Step 9: Fill Any Gaps or Holes

Since I’m not yet comfortable using filler rod while pulse welding, I saved the gaps and holes to weld afterward, once I’d turned off the pulsing. I turned the machine down to about 60 amps, and used filler rod to close up the remaining seams or holes. I used the .035” filler rod for the smaller gaps and .0625” rod for the larger holes.

Step 10: Check for Leaks and Fill Any Holes

Before I went on to sanding, I filled the vase with water to see if there were any obvious holes that needed to be filled. Sure enough, I found a couple leaks! I went back and filled them in with filler rod.

Step 11: Sand Vase With Angle Grinder

Sanding time! I used a variable-speed angle grinder with a 40-grit flapwheel disc attachment to gently grind down the bulkiest welds. Once I’d sanded down the welds, I went over the entire piece with an 80-grit flapwheel disc to smooth out the grain marks, and then again with 120-grit. Finesse is key: You want each face to be a smooth, even plane.

When sanding, make sure to wear safety glasses, ear protection, and a respirator with a particulate filter. Tie back long hair and remove any necklaces, hoodies with drawstrings, or loose clothing – anything dangly that could get caught in the grinder.

Step 12: Check for Leaks Again

Because I’d removed so much material during sanding, I checked again to see if my vase had sprung any new leaks. I found that my vase oozed teeny little tears from microscopic cracks. Rats!

I marked all of the leaks with a permanent marker, and went back to the TIG welder to fill them in with a spot of filler rod. Afterward, I re-sanded those areas with the 120-grit flapwheel disc.

I had to repeat this step three times before my vase held water, which was a bummer. I could have prevented this with thicker and stronger welds. Next time, I’ll aim use filler rod in order to build up better welds!

Step 13: Finish With Scotch-Brite Disc

Once I was confident that my vase would hold water without leaking, I put a Scotch-Brite disc (along with the required adaptor) on my angle grinder and gently went over every face to give the entire piece a satiny sheen.