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: Gardening

Growing and sometimes fixing

Bike Rack Tray Holder: Small Version

Mary wanted to haul seedlings started in half-gallon milk bottles to their destination and I figured they shouldn’t slide around while being transported:

Milk bottle seedling starter carrier

That’s a half-width drawer from the same salvaged collection that produced the Bike Rack Tray Holder and a few minutes with LightBurn adapted the wider cardboard bike rack mount to fit the narrower drawer:

Bike Rack Tray Holder – small – LightBurn layout

Basically, use Node Edit to delete the horizontal lines, move the sides inward by half the difference of the drawer widths, then draw a few short lines to close the gaps.

Hot-melt gluing four layers of cardboard with crossed corrugations, plus three flat bottom layers, got it done:

Bike Rack Tray Holder – small drawer – installed

Those are the same stretchy TPU straps, with an additional link on each rear chain to compensate for the slightly higher block mount and a slightly narrower front block to fit in the slightly narrower drawer handle:

Bike Rack Tray Holder – half-width drawer straps

Of course, the only way to know what didn’t fit was to make a pair of the original ones, try them on for size, then adapt the OpenSCAD code accordingly.

That was surprisingly easy …

2026-09-09
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
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
Dripworks Mainline Leak: Repair Under Field Conditions

A large gooey puddle helped isolate a leak in the Dripworks main line pipe running the length of Mary’s Vassar Farms plot:

Dripworks Mainline clamp – injured hose joint

Much of the tubing between the transfer barb in the buried pipe and the cross coupling lies on the surface, where it’s subject to missteps. This being just a few feet inside the garden gate, it’s no surprise enough missteps caused the barb to no longer seal properly.

So I pulled the barb out of the pipe and deployed the backup pipe clamp I made after fixing a previous mishap:

Dripworks Mainline clamp – installed

You’re supposed to wrap silicone tape while keeping its surface clean, which is obviously impossible in a hole rapidly filling with water draining from the plumbing but the clamp presses the tape firmly against the pipe and seals the leak.

There is, I regret to say, an 8-32 stainless steel washer lost somewhere deep in the muck.

I punched a new barb into the pipe with slightly longer tubing to the cross fitting, in the hope it’ll be more resilient.

Another clamp with its silicone tape snippet stands ready for duty:

Dripworks Mainline Pipe Clamp – assembled

For the record, the Micromark Cutoff Saw has a 3 mm offset between the side of the vise and the left edge of the blade:

Micromark abrasive cutoff – work offset

I still lack a Round Tuit for improving that vise.

2026-06-19
Tour Easy: Bike Rack Tray Holder

Mary starts her garden plants at home, then hauls the trays to the garden in a plastic drawer strapped to the rack on her Tour Easy to avoid crushing the plants in the packs. I finally learned enough to make an adapter mating the drawer to the rack:

Bike Rack Tray Holder – in use

It’s made from four layers of laser-cut cardboard glued together with crossed corrugations for stiffness. I intended make a final version from glued-up plywood sheets, but it works surprisingly well as-is and I may just make another when this one wears out.

The rear view:

Bike Rack Tray Holder – rear view

The front has a cutout for the battery powering the rear camera, with the base height allowing enough meat above the battery:

Bike Rack Tray Holder – overview

The upright posts cradling the drawer may be too skinny for durability, which is why this is a prototype. The inner edges of the posts angle outward by a few millimeters to match the drawer’s mold draft.

Four feet locate the holder on the rack rails just ahead of the Ortlieb pack clips:

Bike Rack Tray Holder – rail detail

The rails are 8 mm ⌀ and the cutouts are 9 mm, because a little tolerance goes a long way. Similarly the tab widths just fit the available spaces beside the rail.

The two flat plates support the drawer and space the uprights to match the Ortlieb clips. I intended to mortise the plates into the uprights, but hot melt glue is wonderful stuff and the joint may outlast the cardboard. In retrospect, the outer edges of the plates should align with the inner sides of the uprights for maximum tidiness.

You don’t have that drawer and likely not the racks, so a picture of the LightBurn layout will give you the general idea for your hardware:

Bike Rack Tray Holder – LightBurn layout

Cut four copies of the uprights in two different orientations, glue them together, then do the obvious thing with the plates.

2026-05-11
Laser-Cut Egg Carton Sprouter
Mary has been using Styrofoam egg cartons to sprout seeds for this year’s garden veggies:

Egg carton sprouter – hand cut

I looked at those artisanal holes and offered to make sprouters with precisely calibrated laser-cut holes.

After the laughter died down, this happened:

Egg carton sprouter – lid detail

Each egg compartment has a drainage hole in the bottom:

Egg carton sprouter – on platform

The LightBurn layout has four shapes in three virtual arrays:
- Drain holes: 3 mm circle, 6×3 array
- Top vents: 25×15 mm oval, 2×1 array
- Side vents: concentric 3×4 & 2×3 mm ovals, 2×4 array
Which looks like this:

Egg Carton Sprouter – LightBurn layout

Because this isn’t a high-precision operation, I align the patterns to the carton using the camera:

Egg Carton Sprouter – LightBurn camera alignment

The two halves of the unfolded carton aren’t the same height, which means the top and bottom patterns have different focus levels and must be cut in two operations.

The laughter made it totally worthwhile.
2026-03-16
Garden Step2 Seat: Hinge Replacement

As fate would have it, the Step2 rolling garden seat took an untimely fall while standing in the garage and broke both its hinges:

Garden Step2 Seat – broken hinge

It’s been out in the garden for maybe six years, so those chunks of plastic are fully depreciated.

Two hours after loading the solid model into PrusaSlicer:

Garden Step2 Seat – new hinges installed

The SiLite tray is well-weathered, but remains structurally sound: still ready for service in the D-Hall breakfast line on the morning after the Apocalypse.

Living in the future works out pretty well.

2025-12-22