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

Champion Hose Nozzle: TPU Washer

There being nothing like a good new problem to take one’s mInd off one’s old problems, I set the Makergear M2 to printing TPU and made a washer for the Champion Hose Nozzle:

Champion hose nozzle – TPU vs rubber washers

It turns out PrusaSlicer can produce models for simple shapes using the Shape Gallery. Subtracting a 7.5 mm cylinder (as a “negative shape”) from a 12.7 mm = ½ inch cylinder does the trick, with the washer all of 2.5 mm thick.

The ID of the thread inside the nozzle is slightly smaller than 12.7 mm, but TPU is bendy enough to let me push it through sideways and reorient it against the front of the nozzle.

The conical part of the nozzle seals against the washer, leaving only a very slight ooze of water, and opens far enough to produce a jet. The TPU is solid enough to not vibrate in the flow and the nozzle no longer howls at low flow rates.

None of the other nozzles in the box have a washer up in there, so they all depend on a much better machined fit than I achieved.

At least the Champion nozzle is once again usable, should it ever emerge from the bottom of the box.

2025-04-29
Champion Hose Nozzle: Needs a Washer?
An email discussion suggested the Champion hose nozzle might, once upon a time, have had a washer between the conical and cylindrical sections.

So I made one:

Champion hose nozzle – rubber washer

The details:
- OD = ½ inch
- ID = 9/32 inch
- 2.5 mm stamp pad rubber
It sealed perfectly, but, just before shutting off, the washer vibrated in the water flow and gave off an ear-shattering (even to my deflicted hearing) howl.

Perhaps a stiffer and thinner washer with a slightly larger OD would work better.

A quick check of similar nozzles in the Box o’ Hydraulics shows none of them feel like they have a compliant washer in there, but any sufficiently old rubber will have long since fossilized.

This seems like a good job for a 3D printed washer with a conical face, made from slightly squishy TPU plastic to ease it past the nozzle’s internal threads. All I need is the ability to print TPU …
2025-04-22
Champion Hose Nozzle: Refreshed Seal Attempt

The battered Champion hose nozzle came into play last fall, leaked profusely when turned off, went to a Safe Place for the winter, and recently emerged:

Champion hose nozzle – disassembled

The conical surface (to the right of the tip) must make perfect contact with the edge of a perfect cylindrical hole in the outer shell to shut off the water, which was obviously no longer happening.

There is no reason why that hole should still be concentric with the outside of the shell, but centering the latter in the four-jaw chuck put the hole within about 0.2 mm of where it should be:

Champion hose nozzle – lathe centering

I defined that to be Close Enough™ and made the hole smooth & concentric with a teeny boring bar and sissy cuts. A drill would likely have worked well enough, too.

Gently filing the nastiness off the cone showed it wouldn’t suffice, so center it while noting the irregular diameter all around:

Champion hose nozzle – lathe centering cone

A skim cut revealed the need for more attention:

Champion hose nozzle – scarred cone

Another tenth of a millimeter improved its disposition:

Champion hose nozzle – improved cone

Gentle touchup with a fine file reserved for special occasions may have been a further improvement:

Champion hose nozzle – finish filed

Add a dollop of silicone grease to encourage the shell to turn much more easily on the O-ring, reassemble in reverse order, and top it off with a new hose washer.

A quick test on a reasonably warm day showed the cone met the cylinder poorly enough to consign this nozzle to the brass recycling box.

It was fun trying, though …

2025-04-14
Vole Trap Boxes: Deluxe Edition

The larger vole trap boxes didn’t survive the early spring rainfall, so we decided to upgrade the fleet with more durable boxes:

Vole Box – finished

I obviously need a larger light box.

The trap boxes come in 7 quart and 3.5 quart sizes, although we expect either will comfortably accommodate a single vole.

They’re made of polypropylene plastic eminently suited for laser cuttery, so I borrowed the holes from the cardboard box setup:

Vole Box – hole cutting

The clamps on the knife bars held the angle block and boxes in pretty much the same position, so I didn’t realign anything after figuring out a pair of magnets would hold the lid to the angle:

Vole Box – lid fixture magnets

The box side is slightly sloped, so I probably should have angled the block to tilt the lid, but this isn’t a precision job:

Vole Box – lid fixture

The white smudges on the lid come from vaporized polypropylene:

Vole Box – fume deposits

The body count thus far is just one field mouse, but the season is yet young.

2025-04-04
Potato Garage

Ordinary potatoes are photosensitive and turn green & bitter when exposed to light, so Mary stores them in a paper bag in the pantry. I recently re-found the cupcake / bread box previously used for battery storage and we decided it would make a great potato storage box:

Potato Garage – installed

It does look like a little garage with a roll-up door, doesn’t it?

The engraving on the top came from the New Garden Encyclopedia:

Garden Encyclopedia – Potatoes – engraving scan

The larger spud definitely has The Stink Eye! Also: tusks!

Threshold the scanned image, edit out a few blemishes, and engrave it atop the box:

Potato Garage – engraved

The result looks rather pallid, but this is not the place for fancy wood finishes.

The alert reader will note a purple sweet potato parked in there, but it’s close to the spirit of the thing.

2025-04-03
Laser-Cut Vole Trap Boxes
We deployed low-effort vole trap boxes a few weeks ago, only to discover no voles checked in, most likely due to wintertime gardens consisting of bare earth. I had weighted the boxes with convenient rocks that pretty much crushed them flat during rainstorms.

So I converted a few dozen square feet of cardboard into better-looking boxes and transferred the traps:

Vole Finger Box – large

That one has a rat trap inside.

Smaller boxes hold mouse traps:

Vole Finger Box – small

Two pairs of 4 mm holes on the bottom flanges fit some spare irrigation pipe holddowns to, yes, hold them down, with those rotten planks keeping their lids in place.

They’re lightly customized “Electronics Boxes” held together by hot-melt glue. The jawbreaker URLs will get you started:
- Large
- Small
Cardboard remains the wrong material, but my stockpile remains well-stocked.
2025-03-24
Hotel California: Vole Edition

Although we had considerable success trapping voles during the last half of the 2024 gardening season, Mary found a description of what might be a better technique: a box with small entrance holes taking advantage of rodent thigmotaxis: their tendency to follow walls. The writeup shows nicely made wood boxes, but I no longer have machinery capable of cutting arbitrarily large wood slabs into pieces.

I do, however, have a vast pile of cardboard boxes:

Vole Box – large

That’s a rat-size trap.

A smaller box has room for two mouse-size traps (one hidden on the left):

Vole Box – small

The general idea: plunk the box in a garden plot, arm the trap(s), close the lid, and eventually a vole will venture inside, whereupon wall-following leads to disaster. Apparently bait is optional, as wall-following inevitably takes them over the trap pedal. I won’t begrudge them a walnut or two, should bait become necessary.

Cardboard is obviously the wrong material for a box in an outdoor garden, but I figure they’ll survive long enough to show feasibility and I can deploy a lot of small boxes before having to conjure something more durable.

Yes, those are laser-cut rounded-rectangle holes: 30 mm and 40 mm, assuming voles care about such things.

Edit: More on voles.

2025-01-28