Coming up this time in ENGI 210: using hot beams of ionized gas to melt through steel and create subpar ninja stars! Couldn’t be more exciting, and to make it even better, I got to use 4 tools that I had never even touched before and work with metal, which I never do. For this assignment, we had to modify a pre-made 3″x5″ diamond shape, plasma cut it, then post-process and finish it to create a spiffy tessellate-able shape.

For my shape, I really wanted a design where the actual cutting of the device and the pattern on the surface were inseparable. I wanted a shape that didn’t make sense without the corresponding pattern, and vice versa. I settled on a layered star design, where the cut shape is an 8 pointed star, but a four pointed star is emphasized by a different color. This gives the appearance of 2 layers of shapes, one star on top of the other. I created this shape in Solidworks so that I would be able to play with the dimensions rather than having to manually set them, like in Illustrator. I pulled the points around and changed line lengths until I came to this design. The design is unfortunately no longer a diamond, but the other corners conform to the same shape, so it can still tessellate with other diamonds. I sent this to the plasma cutter (new tool #1), which admittedly took a few tries due to some disconnected lines on the files. The actual cutting process was smooth as butter once I had the correct settings. I cut 4 separate stars to plan for accidentally destroying one or two.

After plasma cutting, the stars were the right shape, but had terrible edges with lots of metal burrs everywhere. I took them to the angle grinder (new tool #2) to take off the burrs and soften the edges. This took quite a while, but the end results were very nice metal pieces. Unfortunately, the angle grinder did not do much to help the faces of the steel, only the edges. To fix that, since I wasn’t planning to sandblast my pieces or paint them in entirety, I took the pieces to the belt sander (new tool #3). Sanding the faces of the steel plate gave surprisingly good results. All the blemishes of the material disappeared, and the sanding gave a really cool brushed look. This will definitely be part of my metal finishing process in the future.

To create the pattern, I enlisted the aid of another OEDK machine, the vinyl cutter (new tool #4). I have been itching to learn this as soon as I heard about it, and it did not disappoint. I started practicing by creating a few stickers and learned that it was surprisingly easy, fast, and precise. I then created a sticker stencil using a modified file from the one I used to cut. This gave me two stickers, one for the internal (foreground) star and one for the external (background) star. I placed these on two different stars to get a look at what my final design could look like. I chose a metal foreground and black background rather than the other way around. Paradoxically, that meant I needed to develop the black vinyl stickers for the foreground so that those areas would be covered during painting. I cut out a few more foreground star stencils and applied them to my pieces.

I then took the stars outside to spraypaint. I’m not incredibly good at spraypainting, but I made sure to follow the instructions, doing very light coats from far away. My second coat was slightly thicker than I would have liked, but it was still a good paint job, very serviceable. I let the paint dry and came back the next day to peel off the stencil stickers. I really enjoyed how the pieces came out. There were a few tiny defects, but overall, my message of layered stars in a single piece was communicated very well. I enjoyed getting to work with steel for the first time and doing post-processing on something that wasn’t wood. Overall, great mini project.