This week our task was to plasma cut diamonds and post process them! Given a file of a diamond we were encouraged to incorporate some sort of design unique to us and cut it with the plasma cut using either aluminum or steel. I went ahead and used aluminum for mine because that was what we used for our plasma cutting crash course. For my design chose the outline of my birth country, Ethiopia to be cut out in the middle of my pieces. I cut three pieces both for safety and to showcase that my cuts are indeed reproducible, a criterion we will be graded on.

After putting the design on my ai file, I uploaded the result into the torchmate software for the plasma cutter and proceeded to cut! I cut three identical, well spaced (to avoid any disparities in size due to the kerf setting on the plasma cutter) diamonds to be ready for post processing. My first round of post processing included filing off most of the dross on the cut with a file and then some sand paper to clean the pieces more evenly.

After filing and sanding, I decided to go for sand blasting my pieces so it can get rid of any underlying dross and also give it a sort of smooth finish to help with an even coating of spray paint. After sand blasting I noticed that my edges were still sort of sharp from left over dross. I was pointed towards using the rotating grinders in the machine shop. I wanted to keep the rigidity of my edges so therefore I decided to use the grinder against the sides to give them a smoother finish. That came at a price however because at times I would hold the piece against the grinder for a relatively longer period of time which damaged my sides. After feeling like I got smooth enough sides, I decided to move on to spray painting.

 

 

 

 

 

 

For spray painting I went with spray paints with gloss protective enamel that give the job a glossy finish atop the color. I needed three different colors to represent the the three colors of the Ethiopian flag but I only used two spray paints (red and yellow) that sort of have that glossy finish to them. The green color I was using sort of gave my piece a matte green finish which was cool but not what I needed to ensure that all my pieces were alike. Therefore after spray painting it I decided to apply a clear coat over my green colored piece to give it the glossy finish like the other 2. That probably was the only success off the bat that I experienced with spray painting, because what I thought would be the easiest and the most fun aspect of processing tended to be the most tedious. The biggest set backs from this process would be that after spray painting and leaving my pieces outside to dry, I’d find them stuck to the cardboard or wood piece I spray painted them over on. However amount of caution I put in to unstick them proved pointless as a smudge of paint would always come off. In frustration I even sanded a whole piece to spray paint it over again but to no avail as it peeled yet again later. This was happening even though the spray paints I was using were both primers and paints which proves that the problem wasn’t with me but with the Houston humidity which doesn’t allow the pieces to dry very well. At the end I decided to top some of the smudged pieces with another coat of spray paint and finish there! 

Cost Analysis

Machine/Tools provided by OEDK

Labor: 6 hrs at $15/hr – $90

Materials:

Aluminum sheet- 12″ x 12″ of 0.125″ thickness $17.91. Used about 3″x3″ of 0.06″ thickness ~$1.12

Spray Paint- Rustoleum Spray Paint Can $2.00. With the three colors and multiple coats I probably used an equivalent of 1 full can of spray paint- $2.00

Total: $93.12

I made the hourly pay a little bit more than usual due to the tedious aspects of the project which then makes up the majority of the cost. While not accounting for the machines used, I think most of the other costs make sense. For the aluminum sheet I was able to only find 0.125″ thick sheets instead of the 0.06″ we used so I halved the price at the end.