I decided to cut out the state of Florida in my diamond. After adding Florida to the diamond template, I used one of adobe’s features to clean up the shape. Florida has a very jagged boarder so simplifying the shape should help create a cleaner cut on the plasma cutter. I was able to cut out both diamonds during the TA training session. I actually cut three diamonds because the first one got scaled up when the file was uploaded to the plasma cutter software. This gave me a good test piece to use.
I used the test piece to practice angle grinding and sand blasting before moving on to my own pieces. The angle grinding quickly removed the burrs from my shape. The sand blasting took some time to get a nice clean looking finish.
Next, I powder coated my diamond blue as Florida is a peninsula and I wanted a watery look. The glossy powder worked great for achieving the look I wanted. While the powder was curing, I went over the Cricut machine to cut out a vinyl of an alligator. I wanted to do a second coating to create a green alligator on top of my blue diamond. I placed the negative cut of the alligator on my diamond as shown.
I then wrapped everywhere but the alligator in masking tape. With the blue safely covered, I powder coated the alligator. My blue coating wasn’t uniform which I attributed to me doing late sprays. So, for the alligator I just pulled the trigger and blasted it to get a uniform coating.
Now I had to remove the masking tape and vinyl so that they wouldn’t melt in the oven during curing. This was a painstaking process as I had to be super careful to not disturb the powder. The first diamond went well; I caused a slight distortion of the snout but that was it. The second diamond went much worse. Despite this, I proceeded to cure the powders.
The blue coating changed color during the second curing, not sure why though. Although the blue coating isn’t uniform and could be done better, I was really happy with it because it has an ocean vibe to it. The alligators don’t look that great, especially the one on the right diamond. It was at this point that I wished I had used that third diamond to test out my idea. I only used it to practice grinding and sand blasting but not the powder coating. Likely could have saved me a good amount of time because now I had to go back and start over.
Now, I obviously could have just used spray paint. It is simple and easy, but it is not as cool as powder coating and would look worse. My initial thoughts to improve this process was to do a low temperature cure for an extended period of time. If I could cure the powder at a low temperature, then I could keep the vinyl and masking tape on the diamond. Removing the masking tape created a lot of issues so I could do it after curing it should be much easier.
Before doing anything else, I first spoke with Prof. Bisesti to get her opinion on how to improve the process. I then spoke with Dr. Wettergreen as well. Dr. Wettergreen pointed out that the powders should not have been placed on top of each other. The powders are designed to bond with the metal. It does not work as well when bonded on top of each other as I did. This meant that I needed mask the area for the alligator before coating it in blue. Dr. Wettergreen thought that doing a low temperature cure or at least half cure could work.
I began doing some research on the feasibility of a low temperature cure but could not find much. All my searches led me to specific powders that are designed for low temperature curing which would be great if I was able to purchase those powders. At this point I realized I would just have to try it out without any information to guide me. Then to save the day, Prof. Bisesti tells me that she purchased heat resistant tape! This was great as it could go in the oven and removes the hurdle of removing the masking tape before curing.
So, with a new plan in place, I angle grinded, and sand blasted my diamonds again to get the first powder coating off. This time though, I made sure to test the heat-resistant tape with the spare diamond I had. It was a success! It created a very clean mask with sharp clear lines. The blue powder also wasn’t able to diffuse through the tape. It was great!
With Prof. Bisesti, I used the Cricut on the heat-resistant tape to get my alligator cut outs. We double layered the tape and placed it on the white section of a used vinyl sheet. I placed the positive cut outs of the alligator on my diamonds.
I went ahead with the powder coating and curing. This time I made sure to just blast my diamond with the blue and not be on and off with the trigger. It led to a significant difference in the coating. The first image shown is how it looked immediately after cooling.
The first part went flawlessly! When we tested the tape, I had peeled it off while still hot, but I let it cool this time cause working with the hot metal is not very safe and can damage the coating if I am not careful. When we tested, we only did a single layer, not double like for the alligator. I had to grab a sewing needle to carefully peel the tape off. Once I did, it produced a very clean and crisp alligator. All the little details such as the teeth, the ridges on the tail, and the claws can all be seen.
I felt great, the first step went smoothly. A voice in the back in my head said, “Stop here.” I should have listened to it, but I came this far, and I wanted that alligator to be green. I moved forward with the masking. I carefully placed the negative of the alligator on the diamond then masked the entire diamond in the heat resistance tape. Powder coated and cured. When I went to check on it, I knew something had gone wrong.
Once again, I made the mistake of not testing before trying. As a MSNE student I should have known better to not treat the metal coated surface as the same as just the metal. The two are different and will behave differently. I did not test the effect of the tape on the coated surface. It was only tested on the bare metal. While curing the alligator, the blue powder also gets heated up and softens. After removing the tape this is what I had:
Obviously, stuff went wrong. In terms of clarity, the alligator was improved. The shape is better defined then the first time, but the powder coating came out much worse. Not sure what I did differently there. The tape was very hard to get off. Lost the details of the claws in the alligator’s feet. The tape also left adhesive residue on the blue powder. I used acetone to remove the adhesive residue from the piece. Most prominently, is the green all over the place. Now this occurred on the front and back sides.
I don’t think this is due to green powder but rather from the blue powder interacting with the tape. Going back to an earlier image of when I took the diamond out of the oven with the mask of the alligator.
It is seen that the tape has a green color to it. The tape was covered in blue powder before the curing occurred. That time, the powder did not interact with the metal or cause any coloring. In that case the blue powder was on the above the tape. In this case, the blue was below the tape so this probably led to some interaction. It is possible that the green powder diffused through, but I find that to be less likely.
When I masked the diamonds, I was not perfect with the tape. I did leave some small air bubbles and in some places the tape overlapped and in others it didn’t. But honestly, I don’t believe this really matters.
So, going forward, what can be done? I could try low temperature curing to get a partial cure to carefully remove the tape while the powders have partially set as was my original idea. However, this could still lead to issues between the blue coating and the tape. Alternatively, as suggested by Prof. Bisesti is to do the green alligator first then the blue tape. It was clear, that the tape worked great on the metal. So, I can make the alligator first then mask just the alligator. From there I can do two things. One is to take the tape off the alligator, I would have to be very careful, but it might be doable with minimal disturbance to the blue coating. This is not ideal. Second, I can leave the tape on the alligator while the blue powder cures. It seems like the tape and powder interaction distorts the color, so the blue curing would be safe, and the alligator would change color. It might just change shades of green which honestly is a perfectly acceptable trade off. I would test this first before trying again to confirm the effects of the tape on green powder.
Despite not achieving the exact look I wanted, it has begun to grow on me. The mix of green and blue gives off a swampy look. The alligator is very distinct and pops out. The acetone certainly helped clean the look up. It may not match my initial goal, but I am happy with how it turned out.
Overall, I had pushed myself on this homework to do something more challenging. Spray painting was the easy way out, but it is not what I wanted to do. I got to do some problem solving and deduction on how to improve. I learned a lot from this, mistakes lead to growth and learning.
Now for the cost of these diamonds. Starting with labor, I put in about 12 hours since I had to do this twice. A wage of $20 seems pretty fair. So, the total labor cost is $240. This ignores the time put in by the professors in helping me and the TAs which would increase the labor price by a fair amount.
I am going to place a total fee of $60 for the use of the plasma cutter, angle grinder, sand blaster, powder coating system, and cricut.
Lastly, the materials. I used:
- Steel ~$10 for the little section I used on my diamonds
- Vinyl ~$10 for a sheet, so $2 for my use
- Blue/green powder coat – $10 for the bottles, ~$4 for the amount of powder I used
- Masking tape ~ $1
- Heat resistant tape ~ $4
The total price is $261 for two diamonds. The labor can be brought done significantly once I have learned the process. It can probably be done in 5 hours or less with enough practice which would just about halve the price.
