SFO Bravo cut back

I got my SFO Bravo airspace lasercut back. It’s pretty good, but not awesome. A great prototype.

Some thoughts on what to change for a second run:

  • It’s big! 9″ diameter, 2″ thick. It’s just a little too big for me, hard to comfortably hold in the hand. I think I could use the P2 Ponoko sheets and get a 6″ diameter object that felt better in the hand. OTOH that screws up the scale even more; the actual airspace has a 30:1 ratio (60nm diameter, 10,000′ thickness). Maybe I could drop to thinner sheets too, 3mm instead of 4.5mm
  • I don’t love the material (4.5mm light blue acrylic). The translucency is visually distracting and hard to photograph. It’s reflective and a lot of live light inside. And the mirror surface shows fingerprints and smudges from the paper backing glue like you wouldn’t believe. I’m wondering if this wouldn’t work better as a flat white solid material. Or maybe wood, or even metal.
  • After I took the photos I realized I kinda prefer it upside down. Ie: put the surface ring on the top of the object, the 10,000′ ring at the bottom. You can’t just flip it over, you half to flip each sheet (mirror image) to keep east/west correct. But looking top down all you see is one big sheet, no detail. You have to look from the ground to see the detail.
  • Assembly is a little challenging, particularly the 4000′ ring which has almost no detail, just symmetry. If I’m making these as kits I should engrave some notes on each disc. That’d work even better if it’s opaque material.
  • The square spindle hole in the middle with a lasercut matchstick to hold it together doesn’t work well. Has about ±5° of wiggle, either from imprecision in the hole or flex in the stick itself. Really needs to be glued together, I suspect, need to read up on that.
  • The actual cut lines are great. Really worked out well. I don’t think I need to do anything more with the geometry, really.
  • I should engrave a map on the top of the biggest disc. Coastline + airports + major roads, maybe. It’d be neat to engrave some map stuff on the bottom of the discs, too, but it’s a bit tricky with the overlaps.
  • Took about 45 minutes to put together, most of that time peeling the backing off the discs. Would take longer if I cleaned each disc properly and even longer if they’re glued.

Ken suggested making a shape that’s more like a bowl; just the hull of the object. That’d be neat because you could see inside it, too. 3d printing would be the natural way to do that.