Saturday, July 4, 2015



Thought I'd commemorate this year's 4th of July to my favorite superhero-duo, Iron Man and Captain America, via a coin - Stark's first arc reactor on one side, Cap's shield on the other.

Since, you know, they're really two sides of the same coin. Of America. Of heroism. Of--- Ok, metaphors aside. I'm eagerly anticipating Captain America's Civil War movie coming out next year, but I couldn't choose a side, since I love both Cap and Stark. So... I thought it'd be funny to literally flip a coin to decide which side I'd be on.

And a quarter there for scale.
I'm still undecided, if you're wondering.

The designs were laser etched onto aluminum, parted from a rod stock of 6061, using CerMark and an Epilog laser cutter.

Here's how I made the coins:

1) Drafted up to-scale designs in Adobe Illustrator.
In this case, the coins needed to be 1" in diameter.
(Shape fills without outline will be etched)
Export to DXF.

2) Prep your stock of aluminum.
If you have access to a waterjet, use that to cut
circles instead - it's a lot faster than what I did.
In my case, I had to use the cold saw to 
cut a chunk off....

...and then use the lathe to slice off thin disks.

Like so.

Then did some manual finishing with a file.
See, if you had just used the waterjet,
you'd be at step 3 already. :P

3) Mix 1:1 CerMark solution and denatured alcohol.
Then lay a thin coat the metal surface.
Then wait for it to fully dry.
CerMark's a tad expensive, but I luckily had some lying
around in the shop I could use. You don't need much for this-
I used like.... maybe a tablespoon?

The reason we use CerMark is because normally,
the laser will reflect off of metals. The CerMark solution
makes the surface absorbent, thus enabling a proper etch.

4) Cut 2 coin-sized circles in a dummy sheet to hold
the metal coins. (I used 3mm acrylic, 1.015" wide.)
Then, without changing anything about the physical
setup, change your print settings for metal raster,
set your metal pieces in the slots and send your
print to the lasercutter.

Setting-wise for the metal, I used:
100% power, 20% speed.

5) Wash off the remaining CerMark mix with water.
And TADA! You have a metal etch.
Above's a comparison of the acrylic raster test print
to the aluminum raster'd coin.

6) Flip the coins over, repeat 3) and 5),
making sure the coins have a different design
on the other side.

7) (Optional) Flip a coin to decide which side you're on. xD


A few things I'd do differently next time around:
  • Use a waterjet. I could get thinner disks with ridged, or decorative edges, or make extra jut-offs that could hold a necklace string, earring hook, etc.
  • 100% power, 10% speed on the laser cutter.
  • Shake the CerMark longer before use, and mix more thoroughly. The second coin, as you'll see below in the video, didn't etch properly because the chemical solution wasn't mixed properly.
  • Polish the metal surface before etching. Just for the shine factor.
  • Maybe turn this into a necklace? Earrings? Coasters? Poker chips? Haha.

Light, very flippable, Captain America and Iron Man coins!

So even after making this, I can't choose a side. I've had a huge crush on Robert Downey Jr's portrayal of Tony Stark since the first Iron Man, and when Chris Evans first appeared as Captain America, I grew a huge crush on that portrayal too (plus, his Winter Soldier outfit - so cool!). Plus the whole universe they live in, what happens to them, the people they interact with-- Aaaah, so good!

So yeah. My inner fangirl will probably have her heart broken come Civil War day, but until then... LOVE, NOT WAR! <3


In other news, BATTLEBOTS is on ABC! I was part of team JACD, robot OVERHAUL and it was an awesome experience. I have another blog post planned after the whole series finishes, so I'll speak more about it then. : )

Until then, tune in!

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