One of the projects from a weekend in August 2026 was moving the big HVAC unit in the robotics area. Due to a miscommunication, it had been plunked down in the middle of a space we need. So I went in and helped knock a big dirty hole in the wall. Here's one of the other coaches on a ladder, drilling the hole that the vent goes through.

The prior hole just had a flexible tube jammed through it, but I figured I could do slightly better, so I designed an inside and an outside plate.

I fabbed up the inside plate on Sunday (plasma cutter FTW), then spot welded it together and powder coated it. It's a square steel plate with a rolled, slotted flange around a big round opening, powder coated white.

The outside was the next job: a laser cut grate with our logo on it, which I would also powder coat later in the week. That's the rest of this page.

The big round field is a honeycomb of small holes so the air can get through, with the gear and bulb left solid. That's a lot of holes to cut. Here's the laser head at work, close up and then from farther back.

The sheet on the bed of the laser with the pattern cut, and the bed afterward, with the little cut-out slugs scattered over the bed.

The pattern burned into the firebricks shows how serious a 1200W laser is: it did that even when out of focus by almost two feet!

And the finished cut, bare metal, before any coating went on.

I powder coated it in two stages. First a zinc primer, which should give it even more corrosion resistance than the topcoat alone.

Then the white topcoat.

And here it is finished, lying on the workbench.

It's on the outside wall, in an alley that few people go down, which is too bad. I still enjoy seeing it whenever I do.

It looks especially cool when it's backlit at night. I'll have to get a picture of that one of these days.

It took a few tries, but in December 2024 my experiments started to yield better results. This coin has a gear border around an open notebook and pen.

And the same coin from the top.

Some more recent examples: a couple of coins with engraved portraits. I darken the recesses with brass black and then run them in a rock tumbler for a bit to remove the black in the raised portions.

This was basically the first "real" job on my new Gweike M3 Pro fiber laser. The kerf on it is so thin it's ridiculous. The outline of this first 'e' looks rough because the DXF I imported had a bunch of bumpiness in it, which I didn't realize until after the cut; I thought it was the laser, but it was actually faithfully reproducing flaws in the font. The other letters were much better, but even this isn't bad.

The letters stand off the wall on aluminum pins. I needed to make about 25 of these. Here's one, with a grooved and chamfered head at the top and a threaded end at the bottom. Making the other end is three operations (groove, chamfer, deburr) plus chucking and unchucking, and I was pretty happy with how fluid I got it. The threads came from a shop-made tailstock die holder, which lets me knock them out quickly on a bunch of pins.

Here's the full set of letters, with a small box of mounting hardware.

My brother tried them out on his wall.

And here they are up at the curling club, one above each sheet's scoreboard. A closer look at the E, on its standoffs:

June 6: phase one complete. No casualties. Pushing it across plywood to the deck stairs. A brother and a friend are very helpful, especially as they are both younger than me.

A line across the lawn, with the laser at the far end.

The other end of that line: a puller strapped to a tree at the far side of the yard.

The machine wasn't going to fit through the door as delivered, so before it went inside I stripped off everything that added height or weight. The CO2 laser tube, which is glass, came out first.

The control panel's buttons, disconnected from behind.

The lid came off too, which meant unhooking its safety interlock switches.

June 9: inside! And one room away from where it needs to be. Better yet, the remainder of the work can be done in air conditioning. Note that we had to pull off the top and tip it on its side to get through the door.

June 11: in the final room.

Still not a ton of clearance, even after cutting into the wall.

The view from the other side.

The gantry sliding under the cut header, with about a finger's width to spare.

June 13: final orientation.

June 14: back together, with the lid and panels on, and the control console unpacked and waiting for its cables.

The sample cut board that comes with the machine. I believe it was cut on this very one.

I think I already figured out the first upgrade I want.

June 14: success! The kerf is so tight that the piece sits in the cutout on its own. It didn't fall out when the cutout was complete.

June 16: I tried a quarter-inch steel square, target size 25 mm. The measured dimension was 24.870 mm.

And the other direction, 24.941 mm. I didn't adjust for kerf, so the error is roughly the thickness of a piece of paper.

Ventilation. It's also a CO2 laser, which can cut wood and acrylic, much of which smokes a lot more, since the material is being burned and not just melted. It exits out the back, hence the long run, because that's where it needs to be in order not to get blocked by snow in the winter.

The exhaust opening in the wall.

My other lasers are on Fiber Laser Setup and CO2 Laser Setup.

After lasering, the coin goes into a rock polisher for an hour or so. It does a good job of cleaning out the soot from engraving.

But the final look is much improved by an application of "brass black", followed by about twenty more minutes in the polisher. Gives it a bit of definition and age.

Need some ductwork for your laser? Just design and print some! Here's a tall round duct with mounting flanges, and a 45-degree elbow.

I did consider PVC pipe. In the end I didn't go with it because I already had a hole saw of a given size, the fittings are fairly expensive, and I didn't feel like driving over to Home Depot to buy another one. The slicer tells me the cost of the plastic, too: one part I'd just printed was $0.73 worth of PETG.

In April 2025 I finally got the laser set up in a cabinet that other people can be in the room with. It's a plywood enclosure with a green laser-safe viewing window and an LED strip, sitting on a 2x4 stand. The laser glows away inside.