We’re back to another week of crafting and this week it’s all about plasma cutting. Plasma is the fourth stage of matter and produces a pretty powerful cut. The task this week was to cut out a diamond shape out of aluminum or steel. The choice for me came from the decision to try a new finishing technique which required steel. The finishing technique that I was looking into trying was the Rainbow effect on steel. I had seen it done on some YouTube channels with swords, so I attempted to accomplish this.

I began with the sample file of the diamond provided by the professor. I did a bit of searching for inspiration on Google and I decided to implement the Rebel Star Wars logo into the diamond. I looked for a pre-made design of the Rebel logo. I found a decent file and imported it into the Illustrator design. I then went on to change a bit of the design because I knew that the design would not cut very well on the plasma cutter. The reason that I had to change the file is because the plasma cutter cuts away a lot of material. This means that if there are two lines that are really close, then they will cut into each other and ruin the design. I made all the spaces wider to allow for more material to be able to not be cut away.

I then proceeded to cut the design on the plasma cutter. The process is pretty straightforward and is in a way similar to the laser cutter. The steel was loaded onto the cutting bed and my design was cut. Unfortunately my first attempt to cut it did not go as planned. I had grouped both shapes (diamond and Rebel logo) together and created a male cut. This made the software cut around the outer part of both shapes. This made the design not cut out correctly and the logo outline was lost. To rectify this, I tried to ungroup both shapes and use a male outline for the diamond cutout and a female cut for the Rebel logo. This worked perfectly!

 

I now had a total of six diamonds. Three with the wrong profile Rebel logo and three with the correct cutouts. The next step was to implement the Rainbow steel technique that I wanted to tryout. First I had to prepare the surface of the steel. I first used the angle grinder to remove the slag that the plasma cutter produces as a result of melting the metal as it cuts. This step was done using the angle grinder. This step also served to remove some of the rust that had formed on the steel. The next step was to remove the rust entirely. This was done using the sand blaster. This was my first time sand blasting metal, but it was pretty straightforward. Similar to cleaning the pavement with a pressure washer, the sand blaster shoots out compressed air along with sand and removes the imperfections in the metal. In this case the sand blaster was used to remove the rust.

Afterwards, I polished the metal using a polishing wheel. This made the surface incredibly shiny. I figured this would help create a nice shiny rainbow effect. After all of the diamonds were polished, it was time to bring out the fire. To heat up the metal I used a large blow torch and aimed for a blue flame so that the metal would heat up, not burn. At first, the metal was heating up nicely and I could see that it was turning red hot. According to my Instructables source, at this point the metal should be dipped into motor oil to create the rainbow effect. Well…the metal was so hot that the motor oil caught a bit on fire (Whoops!). Luckily it was only a surface fire and we were outside, so it was okay. After the metal cooled down in the oil, I inspected it and it was not the effect I was going for. The blow torch was just too hot and charred the surface of the metal. This was not what I expected to happen so I decided to try a different, more gentle, heating method.

I then went on to use a Bunsen burner to gradually heat the metal. This was a more gradual heating and when inserted into the oil, did not cause any fire. The rainbow effect that I was going for was not overwhelmingly present, so I decided to change tactics and try a different finishing method. Although I had a bit of success with the rainbow effect, I do not have enough experience with metallurgy to know that process to use. The ideal person to ask would be a blacksmith. I may not have done the steps correctly from the Instructables, or maybe there is a specific type of steel that is required. This is definitely something I plan to look into for the future.

I decided to use a spray paint finish instead. I sandblasted the diamonds again, applied a primer, and then began to put down a total of three layers of red spray paint. The reason for sand blasting again was to take off the polish so that the paint would stick better. After getting inspired by some of my classmates, I also decided to incorporate a splash of black paint to go along with the Star Wars theme I had for the pieces. In addition to the spray paint, I thought that it would be an excellent opportunity to try to laser etch the spray paint using the laser cutter. Id had not done something like this, so I thought it would be neat to try. I first tested on some of the extra pieces I had and found out that the R2-D2 that I intended to etch was not very visible. I modified the file and made it bigger so that the main silhouette would show well. The end result of the etching was surprisingly amazing. In the image below you can see the evolution of this project, leading up the final result.

To recap, the steps taken for me were: 1) Cut the shape, 2) Angle grind the slag, 3) Sand blast the surface, 4) Polish the metal, 5) Sand blast the surface again (to get rid of the polish that was going to be used earlier), 6) Surface Primer, 7) Spray paint, 8)Laser Etching R2-D2, and lastly 9) Clear coat.

Overall, it was a pretty lengthy process with a lot of paint pealing and flame torching, but I believe that I learned from the task. Firstly, I learned that Im not a blacksmith and that spray paint in humid environment makes it really difficult to get the surface perfect.

The cost of this was pretty low. In terms of labor, it was about 6 hours between cutting, polishing, sand blasting and painting/etching. The material itself was about 5$ (19$ sheet with approx. 1/4 used). With 10$ an hour, the price comes out to 65$.

As a personal critique, there are differences in the two pieces. While the main shapes are the same, including the little slot that was produced by the plasma cutter at it was exiting, there are artistic differences that you cannot accommodate for. The black splash on both pieces are different in their own way. In part this has to do with the fact that spray paint is hard to control. I believe that this makes each piece unique, and dispute both pieces being exactly the same, the spray makes each its own work of art.

That’s all for now! Thanks for reading and go make something awesome!