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.

Category: Home Ec

Things around the home & hearth

Water Heater Anode Rod Replacement
The Bradford White AeroTherm heat pump water heater that Came With The House™ has been running for three years. Based on previous experience with the same City of Poughkeepsie water, it was time for a look at the anode rod.

Which, as always, required the Greatest Ratchet with a foot of extensions getting the 1-1/16 inch socket down to the rod:

Water Heater Powered Anode – socket wrench

Remember to:
- Turn off the water heater power
- Shut off the inlet and outlet valves
- Open the drain valve to relieve the tank pressure
- Only then loosen the anode rod
Seeing the first few inches justified extracting the rod:

Water Heater Powered Anode – old rod top

Due to low overhead clearance and inauspicious pipe locations, I had to hacksaw the bottom third off to extract the rod:

Water Heater Powered Anode – old rod overview

Water Heater Powered Anode – old rod bottom

With the rod out, draining a few gallons of water into a pan didn’t produce any notable gravel, so I didn’t do a complete flush. Much to my delight, the drain has a ball valve!

Given that this is a fancy water heater and I no longer regard anode rod maintenance as a fun-filled activity, I installed a Corro-Protec powered anode rod for cathodic protection without all the crud:

Water Heater Powered Anode – Corro-Protec parts

The wall wart proclaims 15 mA with a green LED indicating it’s hard at work:

Water Heater Powered Anode – Corro-Protec wall wart

The data plate on the back reports 24VDC 15mA, but, being me, I poked at it with a handful of resistors:

Corro-Protec power supply measurements

The electronics could be as simple as a 24 VDC wall wart feeding a 425 Ω series resistor and a transistor switch lighting the LED for currents a little over 6 mA.

A quick ohmmeter check shows the powered rod electrode is open-circuit with respect to the tank, as it should be without much applied voltage. Applying +24 VDC from the wall wart drives 15 mA into the water: the rod is hard at work.

I’ll take a look at it in a year or so just to see what’s going on in there …
2026-08-05
July 4 2026: Deadfall

Heavy winds during an overnight storm on July 4 2026 brought trees down across Dutchess County and caused widespread power outages. Our little generator justified its existence by preserving our food for about 24 hours, but other folks were without power for three or four days.

A large branch fell across the Carriage Hill entrance:

Carriage Hill Bridge – treefall – 2026-07-07

The terrain and lot layout in Carriage Hill often requires heavy equipment for tree maintenance:

Tree Clearing Crane

Many trees along the Dutchess Rail Trail toppled as their root balls rotated or simply broke off:

Rail trail north – treefall B – 2026-07

Others snapped and took out the fences:

Rail trail north – treefall A – 2026-07

We ride as far from this deadfall as we can:

Rail trail south – treefall – 2026-07

Cleanup continued for weeks and we wish the crews well.

2026-08-04
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

Photo Backdrop: Crossbar Improvement

The instructions for the Photo Backdrop frame (upon which we hang Mary’s quilts for photos) suggest the crossbar fits on like this:

Photo Backdrop - OEM crossbar installation — Photo Backdrop – OEM crossbar installation

The slot in the bottom is wider than the M10 stud, so the crossbar tends to flop around while assembling it overhead. I immediately replaced the wingnut with a chunky knob for better griptitude, but was never happy with how poorly the whole thing fit together.

This is dramatically better:

Photo Backdrop - fitting installed — Photo Backdrop – fitting installed

The crossbar is upside-down from the OEM instructions, but the bottom of the gray plug holds the tube firmly to the tripod while the nut seats firmly on the plug’s flat top:

Photo Backdrop - fitting top view — Photo Backdrop – fitting top view

A snippet of 3M 300LSE adhesive sheet holds the plug in place, so that’s one less thing to fiddle with on each end.

The solid model holds no surprises:

Photo Backdrop Fittings - solid model — Photo Backdrop Fittings – solid model

Of course, it builds with the flat end downward.

The OpenSCAD source code as a GitHub Gist:

	// Photo backdrop fitting
	// Ed Nisley – KE4ZNU
	// 2026-07-01

	include <BOSL2/std.scad>

	Layout = "Show"; // [Build,Show]

	/* [Hidden] */

	ID = 0;
	OD = 1;
	LENGTH = 2;

	HoleWindage = 0.2;
	Protrusion = 0.01;
	NumSides = 324;

	Clearance = 0.3;

	$fn=NumSides;

	Tube = [23.0 – HoleWindage,1*INCH,100.0]; // arbitrary length

	Aperture = [24.0,15.0,100.0]; // oblong nut hole, arbitrary Z

	Washer = [10.5,20.0,1.5]; // M10


	//—–
	// Define things

	module Fitting() {

	difference() {
	union() {
	intersection() {
	xcyl(Tube[LENGTH],d=Tube[ID]);
	cuboid(Aperture,rounding=Aperture.y/2,edges="Z");
	}
	cuboid([Aperture.x,Aperture.y,Tube[OD]/2],rounding=Aperture.y/2,edges="Z",anchor=BOTTOM);
	}
	cyl(Aperture.z,d=Washer[ID]);
	}
	}




	//—–
	// Build things


	if (Layout == "Show") {
	Fitting();
	}

	if (Layout == "Build") {
	up(Tube[OD]/2)
	xrot(180)
	Fitting();
	}

view raw Photo Backdrop Fittings.scad hosted with ❤ by GitHub

2026-07-02

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