Planning and Design
This week, I will be creating a steel diamond shape and adding flare by customizing the shape and post-processing it.
I’m thinking a falcon, with crisply angled wings and tail, would fit in the diamond shape really well. This photo of an American Kestrel is as close to diamond shaped as I can find.
A little magic from Illustrator, and it fits perfectly!
Processing
The outlines are then cut out of 1/8″ steel on the OEDK’s plasma cutter. The lead in was not gentle enough however, and left small notches in the outer tail of each.
A bit of surface grinding takes off the rough edges and leaves the outlines ready for finishing. (Top is raw from the plasma cutter, bottom has been surface ground.)
Post-processing and Finishing
To begin, I sanded the birds in 200 grit intervals up to 1000 grit and then jumped to 1500 and 2000 for an almost mirror finish. I also lightly filed the edges to remove sharp edges, but left most of the wavy edge made by the plasma cutter as it resembles feather edges!
I then taped the wings and tail and sand-blasted the body to give it matte finish which contrasts nicely with the shiny wings. This is much like a real bird where the highly structured flight feathers reflect light much better than the downy body feathers.
A clear-coat finish and a label on the back completes the project.
Analysis
I didn’t sand the back of the birds and left the hot-rolled black color which gave the wings a bi-colored look, also much like a real bird. However, this meant I had to leave the filing and grinding marks on the back edge, which I dislike. I also made the mistake of carrying the almost finished birds together, which marred the smooth sanded finish. Finally, while the clearcoat dried on the front of the birds overnight, the rough sandblasted body on the back collected dirt and rust, which I did not have time/ability to refinish. This left a brown streak on the backside of each bird and looks terrible.
The cost for this proof of concept/tool usage design is as follows.
| Item | Quantity | Cost |
|---|---|---|
| 2’x4′ 12ga hot-rolled steel | 1/40th of a sheet | $79.80 /40 = $2 |
| Clearcoat | ~1/50th of one bottle | $5.30 / 50 = $0.11 |
| Plasma Cutter | 1h | $80/h × 1 = $80 |
| Sandblaster | 10 min | $60/h × 1/60 = $10 |
| Labor | 4h | $15/h × 4 = $60 |
Materials cost: $2.11
Labor and Tooling: $150
Total Cost – $152.11
