The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Laser Cutter

Laser-cut Window Screen

Having just cleaned a bunch of gunk out of the bottom of the worm bin, we decided to try a layer of window screen to keep both gunk and worms out of the sump.

A roll of window screen Came With The House™, minus label or provenance, that felt like some sort of plastic, perhaps with a glass core.

The bin has a 19-¼ inch = 488 mm ID with 10 thin support struts around the perimeter. Laying out a circle and cutting it accurately by hand seemed like a chore, even though the screen cut easily with ordinary scissors.

The diameter just barely fit on the laser’s 700×500 mm platform, so I laid it out in LightBurn:

Laser-cut window screen – LightBurn layout

For lack of anything smarter, I applied the same setting as for the faucet gasket material (30 mm/s at 25% of 60 W) and Fired The Laser.

As far as I could tell while the laser was trundling around the circle, absolutely nothing happened other than maybe burning off a coating with a little discoloration on either side of the path.

However, the circle lifted out with zero drama:

Laser-cut window screen

And was a perfect fit in the worm bin.

Color me surprised!

I have no pictures of the happy results, as all this happened in the few minutes between “We should try a screen”, dropping the cut screen in place, and reassembling the bin.

I think the screen would cut just as well with a higher speed. If the screen works and we need another, I’ll run a few tests first.

2026-07-17
Chest Freezer Basket Shims

Our new chest freezer has three baskets sliding along ridges just under the lid, but they seem to be just slightly too short for the ridge spacing. After having a basket fall off the rails once too often, I cut shims from 3 mm white acrylic and stuck them in place with double-sided foam tape to soak up the extra space:

Chest freezer basket shims

Each shim is 300×8 mm with the neatly rounded corners that are easy to do with a laser. They may not look like they grew there, but it’s tidy enough.

Perhaps the situation should have become a warranty claim, but a few minutes applying a tool to material I have on hand made the problem Go Away.

Which is entirely good enough for me and pretty much what I do around here most of the time anyway.

2026-07-15
Shower Mat Hangers

A new Gorilla Grip shower mat defeated the spring-loaded clip its predecessor dangled on between showers, so I applied a contour gauge to the shower stall, copied the shapes to paper, scanned them, then fit some curves:

Shower Mat Hanger – curve fitting

Combine the two to get a model of the shelf, subtract it from a rectangle, and produce a cardboard test piece:

Shower mat hanger – cardboard test 1

Put a hook on the bottom, a small bump on the top, and round the corners:

Shower Mat Hanger – LightBurn layout

Function-test a cardboard pair:

Shower mat hanger – cardboard test 2

They clear the hump along the edge and fit snugly across the front and sloping underside, so make an MVP from 6 mm acrylic:

Shower mat hanger – acrylic

Laser-cut acrylic may be too brittle for the job, but it gets the mat off the floor for drying and we’ll see how this works before doing anything more complex.

2026-07-14
Workbench Scrap Can

You don’t have one of these, but your bench needs something like it:

Workbench scrap can

Tiny Bandsaw perches just above it and now I have a place to drop the scraps you see collecting in its tray.

The can hangs by its rim from a completely kludged two-layered MDF hook stuck to the metal table frame with good 3M foam tape:

Workbench scrap can hanger

It’s not in the way of Tiny Bandsaw, because I stand at the left end of the bench, and it’s not in the way of the Sherline / LinuxCNC keyboard, because I stand to its right. So far, so good.

Should it fall off, I’ll think of something better.

2026-07-07
Dremel Collet Holder

A set of Dremel-knockoff collets & chucks will come in handy for an upcoming project:

Dremel collet holder – in use

All the parts arrived jammed into the clear box where I had trouble figuring out the collet sizes.

A few minutes with LightBurn and a scrap of 6 mm white acrylic produced a collet holder / organizer:

Dremel collet holder – detail

Seen in the cold light of day, the upper 1.8 and 2.0 mm collets look swapped, which pretty much demonstrates the need for the holder.

The nice engraved letters come from scribbling a chisel-tip black marker before peeling the protective paper off the acrylic. The black lacquer crayon I intended to use must be in a different box than the markers, but the results suffice for the intended purpose.

2026-07-06
Hose Nozzle Flow Restrictors

Mary wanted less pressure in the spray while watering her plants and I suggested replacing the nozzle’s washer with a flow restrictor:

Hose Nozzle Flow Restrictors – assembled

The 3D-printed TPU base is squishy enough to act as a hose washer:

Hose Nozzle Flow Restrictor Base – solid model

A 1.5 mm thick acrylic orifice plate snapped into the opening takes advantage of the laser cutter’s precision:

Hose Nozzle Flow Restrictors – LightBurn layout

For lack of anything smarter, the holes have areas that are powers-of-two smaller than the nozzle’s 14.2 mm = 158 mm² internal passage: the hole labeled 8 is 158/256 mm² = 0.62 mm² → 0.9 mm diameter.

Rather than figuring each hole’s diameter, just divide the previous diameter by √2 or rescale it by 100%/√2, which LightBurn can evaluate directly in its Numeric Edits fields. The as-cut holes are larger than their nominal size by about 0.1 mm, but any errors that might cause are definitely in the nature of fine tuning while watering the plants.

The nozzle’s Shower pattern (on the left in the picture) has a 6.8 L/minute = 110 ml/s flow through an ordinary garden hose washer. The four smallest aperture plates produced these flows:

Hose Nozzle Flow Restrictors – flow vs dia

The flow should scale with the square of the aperture diameter, which I could bully those points into suggesting, but the measurement accuracy produced by filling a gallon jug while tapping my phone’s stopwatch doesn’t justify anything fancier.

The two smallest apertures reduce the Shower pattern to a very gentle spray requiring far too long to put enough water on the plants. Mary now uses an old plastic sprinkler head with enough holes to produce a dense spray with very little force, with the flow set by fifty feet of PEX pipe running across the width of the house from the town water inlet to the hose bib.

It was a fun exercise and I learned a little more about printing TPU and fitting acrylic parts therein:

Hose Nozzle Flow Restrictors – prototypes

2026-06-29
Methanol Package Labeling

I am so glad methanol is a liquid, not a crystalline powder, because this could be totally misinterpreted:

Methanol package label

A recent LightBurn forum discussion pointed out methanol is a good solvent for borax to produce dark-brown to black laser engravings in wood. In round numbers, 20% w/w borax will dissolve in methanol at room temperature.

I understand the toxicity warnings and don’t plan to spray it indoors. OK?

2026-06-24