Laser Cutter at The Mullet


We have a plan, but we could use a few more people to help see it through.

What’s done:

  • Laser is roughly in position. See the plan below

What needs to be done:

  • Set up the second arlink bench. This will be for the operator’s laptop, project assembly, etc. Thx @JohnC
  • Make a little keyboard shelf, mount the monitor to the exposed 2x4s on that wall, put the computer below
  • Run a cat5e cable to this area. (@TyIsI to advise) We need 3 devices connected, so we can use a switch as we did at cook. We have a switch for this purpose.
  • Set up the raspberry pi, and peripheral control system
  • Set up the chiller and air assist systems
  • Move the ports on the filter box to better locations, rough in the ducts and blowers (@kleenpwr to advise on this). More detail at
  • We have a 120VAC outlet nearby, but we also need a 240VAC one. We will eventually get this, but @JohnC is going to make a nice extension cord so we can use existing power from the other side of the room in the interim.


  • Install the laser tube, do an alignment, and do some test cuts to validate the filter performance

I will be at VHS this Sunday, Feb 24th, from 1pm-5pm working on this, and could use a few people to help. This task list doesn’t have to wait for then though. Please coordinate on Slack#laser and let me know if you want to help tackle any of this.


I set up the 2nd arlink bench and moved one of the glass display cases next to it so people can show off their laser projects.


@kleenpwr and I put in a full day today on this and got a lot done. Here’s where we’re at:

  • Moved @Petetheviking’s new lazer material storage unit into place
  • Cleaned the inside of the filter box, the fans, and the few ducts that we’re reusing
  • Bought a bunch of new ducts and filter media
  • Roughed in most of the ducts. We plan to wye off to have a second fan in parallel, and then out through two dryer vents
  • Built a keyboard shelf and monitor mount

In addition we’ve had some folks pick up some tasks in the last few days:

  • @JohnC set up the arlinks and ran a 240V extension cord
  • @TyIsI ran network
  • @Arrgh ordered some charcoal media for us online

Here’s what we need now:

  • Top priority: Permission to punch two 6" holes in the plywood “window” to mount two dryer vents. If this is something we need landlord approval for, we need to prioritize this. @rsim we need your support on this.
  • @Petetheviking there is a small additional area that could have more material storage. If you’re keen to keep building, you could tack on another section and take it right to the wall. We would put the chiller on top of it. Otherwise we will put the chiller on the floor in this spot.
  • @jade is planning to do some painting behind the laser arlink benches. I think this is a “nice to have” but I want to ensure our benches are returned and we can proceed next weekend.

Current estimate for laser: At least another 2-3 weeks. That assumes that our new filtration scheme is sufficient, otherwise it will be back to the drawing board.


Happy to keep building if it can wait until next weekend. Getting low on materials but I can probably scavenge enough from the woodshop


@kleenpwr measuring flow (corroborated using two different methods).

Our plan is to have some existing and new sensors wired up:

  • Differential pressure across the fan
  • Differential pressure across the filters (these are two absolute pressure sensors, so we could add more between the different filters stages if we need)
  • PM2.5/PM10 sensor at the filter outlet
  • VOC sensor at the filter outlet


Last week @kleenpwr and I cut the hole in the wall to finish installing the vent, and then we set up all the rest of the laser peripherals: chiller, compressor, access system, controller PC, etc. We installed the laser tube and did a very basic quick alignment. We verified that it was working, and stopped there.

@Arrgh went and got us a metric boatload of activated carbon so we’re able to fill all the trays right up.

Today we worked on testing the filtration system. We tried a bunch of configurations, and even sealed off one side of the filter box and made an acrylic window so we could observe the smoke.

The results are promising. We tested with worst-case etching wood and acrylic and found that the odour outside varies between “barely noticeable” and “definitely noticeable but probably acceptable”. This is with brand new filters in a configuration that’s somewhat more principled than what we did at Cook St.

There is a laundry list of little improvements we could and should make to give ourselves more margin. The filter box door doesn’t seat very well with the ratchet strap. It’s critical to ensure that the filters are sealed inside so they can’t be bypassed — so tape around the outside of the filter box door doesn’t really help. Even with these improvements we’re going to have to maintain our filters more regularly, which is going to cost money. Unlimited free lasering may not be feasible anymore.

We’re still a couple weeks off from any chance of opening the laser for general usage, and it might be with limitations. It’s been slow going because there’s only two of us working on this. We could use some help to make improvements to the construction of the filter box, doing some sensor work, or other tasks. Drop me a line if you care to help out.

Anyone want laser cutter training?