The Red ‘G’ | ENGI 210: Prototyping and Fabrication

For the last homework before our midterm (:o), we learned how to use the plasma cutter on steel, a very difficult post-processing of steel, and giving aesthetic finishing touches to our pieces. In addition, we created each piece twice to practice and ensure the precision of our skills. In this installment, I wanted to create something I am proud of gifting to someone; I made a “G” that resembles the gym logo I go to! I will give this to the owner as soon as it gets graded.

Step I: Designing the Piece

To design this homework piece, I used Adobe Illustrator and worked over the provided diamonds to maintain a correct scale. I made two models to try out; the second one was created after meeting with a TA and suggesting changes. In the image below, you can see two diamonds. The first one on top was a first trial that did not work correctly, and the diamond on the bottom has been modified to create a better cut. I added circles at the ends of the piece so that it can be hung or sown onto a backpack.

Step II: Cutting the Piece

To cut this piece, I used the plasma cutter in the OEDK. I uploaded the file to the computer, and using the available software, I moved and manipulated my piece to my desired spot; once it was set to my liking, I adjusted the nozzle on the plasma cutter to an appropriate place on the metal sheet provided and started the process.

I cut two pieces on the metal sheet. And thankfully, my pieces came out with the whole “G” showing inside of the diamond. Nevertheless, there are some marks on my pieces where the machine started cutting (these became visible during the post-processing).

Step III: Angle Grinding

To begin the post-processing, I used an angle grinder to get rid of the dross left around the cut. I clamped the piece onto the edge of the table, leaving the part that I was going to work on over the edge. And there was a specific chunk of dross I was particularly satisfied to take off.

Step IV: Filing and Sand-blasting

I clamped my pieces on a table and used different file sizes to file down all the inside edges; this was a little difficult because I had a very thin part of the cut. But I smoothed my pieces’ edges with a lot of determination and elbow grease.

To finish the post-processing of my pieces, I sand-blasted my pieces until I was happy with the color and texture of the metal.

Step V: Powder-coating (and Un-powder-coating)

In what I thought would be the final step of my process, I set up the powder-coating area and used the red powder to coat my pieces. Later, I excitedly put my pieces in the oven, when tragedy struck: my piece got stuck to the inside of the oven.

After a bit of stress, I decided to remove the coating by angle-grinding it and sand-blasting it again. Even after this process, there were still some parts of the powder coating that were stuck on the piece.