Ahh the plasma cutter, what a terrible machine. I did not have good luck with the equipment, however I will take the blame for some of it… and it led to lessons learned.
Little text coming up on plasma cutter computer – causing error because too small to lead in to (also would have messed up the part bc not supposed to be there)
My first go-round with the equipment was last Wednesday, and I had errors because when creating my diamond file I simply added text without changing the whole thing into an outline. With this, the machine got very confused and was making me change my font… which caused a small line of text to show up on the file on the plasma cutter computer. 45 mins later with no progress I was kicked out for a class happening in the machine shop. After speaking with Dr. Wettergreen, I was able to resolve the issue (Command Y). Once my file was fixed I hit the machine shop for round two (Thursday). This time, while doing a dry run we noticed that the plasma cutter was erroring. The head of the plasma cutter was staying up in its initial position rather than coming down to meet the piece of steel. After some troubleshooting by Douglas we were able to get the head down, but the plasma cutter kept getting stuck very soon into the cut. We figured it was another error with the machine, but it turned out that my font was too small which caused the turns to be too tight for the machine to handle.
Successful plasma cutting!
Showing the cut in real time via computer
Round three was Sunday night and Jhalak and I finally achieved success. I had upped the font size and the cuts went off without a hitch (YAY!). We were able to get our 5 pieces each in the hour. We came back Monday night to work with the angle grinder and metal files. The angle grinder was pretty quick and easy, however it didn’t get off all the slag stuck in the middle with the more complex cutout of “hi”. To get rid of the rest of the slag for a smooth surface we went downstairs to the files. Our mantra throughout filling the diamonds was “this sucks”. Long story short, everyone was right when they said the metal file takes off very small amounts of material. I mainly used the long triangle flat one to grind back and forth over the surface, but also did the thin rod-like one to smooth out edges of letters. That part took us a good while until we were finally happy with the quality.
Five identical-ish “hi” diamonds
Front/back – look at that post cut slag
That [angle] grind
Pre-filing
Post-filing… she ain’t pretty but she’s smooth
Post-file metal dust
In the sandblaster
We moved into our sandblasting phase next (Tues/Weds) to get a uniform finish. The sandblaster didn’t take an inordinately long amount of time, but it did take a number of coats/go-overs with the sand gun before the finish was perfectly uniform and a nice shade of silver.
Upon coming back Thursday, I was in for another disappointment. My previously perfect pieces, wrapped up nicely in a clean paper towel, had rusted overnight. While they no longer look at great as they first did, the Houston humidity is not something I can compete with, so I decided to let it go and move on. I had cleaned up and sandblasted 3/5 pieces, so went forward with coating one with a clear gloss spray to determine if I liked the finish. The coat ended up turning the piece a darker shade of gray, which was not my favorite. After making the decision to not coat my two remaining identical diamonds, I added notes with the info on creation and turned in my finished product!
Top: final front & Bottom: final back
Top: final vs Bottom: initial
Top: final vs Bottom: coated
Total cost for 1 diamond: $34.83
Materials- Steel: 24″x36″ sheet of steel $14.48 @ 15in^2 = $0.25 for a diamond
Labor- $7.5/hr @ 2.5 hr to cut 5 diamonds, 1.5 hr to file 3 diamonds, 1.25 hr to sandblast 3 diamonds, 0.25 hr to coat 1 diamond and label 2 diamonds = $3.75 + $11.25 + $9.375 + $1.875 = $26.25 for a diamond
Overhead for building and machine use- $5/hr @ (same times as earlier) = $8.33 for a diamond
