Original Title: “This is what I call a super 「Muppet」 3”
It’s Brian again. This is my blog post for the Plasma Cut + Post-Processing project. I can’t think of anything snarky to say here, so let’s get started.
I decided to go with a kind of ninjastar design, like this. I used to make the paper kind a lot as a kid, and thought it would be cool to make one out of metal. Obviously I’d have to mess with the scaling for it to fit the diamond template.
(1) Base Illustrator file from Canvas, minus the extra two diamonds
(2) Creating guidelines for my reference
(3) I made a box here as my inner dimension for the triangular concave cutouts to come.
(4) Creating the actual star shape, using the Line tool.
(5) Deleting reference lines and base diamond shape.
(6) Used Shape Builder to combine the lines into one shape (We initially ran into some trouble in Torchmate because the lines in my shape weren’t actually connected, which made disjointed tool paths. Shape Builder fixed that).
(7) Setting up the Plasma Cutter (FYI the laminated color booklet in the machine room is missing steps!) We (me and Adulfo, who cut during the same session) used 1/32″ steel sheet for our material.
(8) Getting schooled by God-Emperor Joe on using a disc sander and a magnetic chuck to remove slag and surface rust.
(9) Me makin’ sparks fly
(10) I used a magnetic chuck during disc sanding to keep my pieces from flying around. It uses a magnet to induce a magnetic field in ferrous (read: STEEL – anything with iron, actually) metal and hold the pieces steady.
(11) My pieces, all slag removed with the disc sander.
(12) I remembered wanting to sandblast my bike frame, but sandblasting my plasma-cut parts would have to do. I think this playing with the spray gun was the most fun I had during this project. The wood shop is freakishly hot, though. My goggles got all fogged up.
(13) Got that nice chalky texture from sandblasting.
(14) I ended up choosing yellow paint because it’s a cheerful color and I just really like yellow. Here I am doing super light coats, just dusting the paint on.
(15) Comparison shot between painted and unpainted. Wheee
(16) In a kind of impulsive decision, I decided to use a heat gun to cure my paint faster. It worked pretty well, actually. I was applying new coats every 5 minutes instead of half an hour.
(17) I sanded with 400 grit sandpaper between each coat, and with 400 and 1000 before moving on to clear coating.
(18) All done! Two coats of clear enamel applied and sealed with a heat gun!
Mistakes:
I did run into some problems during this project. When I added the clear paint, it pooled and stripped away the previously-dry layers underneath, which rubbed off when I picked them up. Also, the overall finish came out really ugly (not really captured in picture 18, unfortunately). Since the yellow paint I used already had a gloss finish, I regret not sticking to that and skipping a clear coat altogether. Maybe it’s a technique thing, but in everything I’ve ever painted (bikes, nerf guns, etc.) I’ve never gotten a clear coat that turned out right. They always come out cloudy or strip the layers beneath, like with this project. Overall, I think the paint job turned out acceptable, but I’m kind of annoyed because it could have been a lot better.
(9/20/18): After sleeping on it, I decided I wasn’t satisfied with the previous paint job, so I came to the OEDK, disc sanded and sandblasted the paint off once again, then repainted again, this time without the clear coat. I left out pictures because it was the exact same process as before, but here is how they turned out.
Cost Analysis:
- Material: 0.1275 lbs 1/32″ Steel sheet (weighed with scale), priced by AgMetalMiner at $0.41/lbs –> ($0.41)*(0.1275) = $0.05
- Plasma Cutter Operation: ~5 minutes of Torchmate operation (discounting computer time), with a suggested operation cost of $90/hr –> $90/12 –> $7.50
- Sandblasting Operation: ~20 minutes total (both rounds of sandblasting), priced by CostOwl at $40/hour –> $40/3 = $13.33
- Sandpaper: A 5-pack of assorted grit sandpaper costs $2.97 at Walmart.
- Paint: Zoro carries Rustoleum’s Sunburst Yellow Gloss at $4.14/can (even though I didn’t use the full can) –> $4.14/10 =$0.41 for paint
- Labor Costs: nah
Subtotal: $24.26 for three shapes –> unit price = $8.09 per shape
Muppet Discount: -$20
Total: $4.26 (nice)
AI File download: link!
Thanks for reading!
Brian Builds 