Home Ec – Page 5 – The Smell of Molten Projects in the Morning

ResMed ClimateLine Heated Hose: DOA

Mary plugged a new ClimateLine heated hose into her Resmed Airsense 11 CPAP machine, spent the night feeling a bit chilly, and got an error message in the morning that boiled down to “Bad Hose”.

Unsurprisingly, the new hose looks just like the previous ones and the old picture remains relevant:

The new hose has the same 12 kΩ resistance between the two outer contacts: the thermistor is fine.

The two inner contacts are an open circuit, not the expected 10 Ω: the heater element or (more likely) a connector joint failed. We don’t know if it was DOA or failed during the first use, but it does not respond to the usual wiggling and poking.

Her experience with Lincare’s Customer Disservice has been so terrible she refuses to start a warranty claim. She’ll continue using the old hose until it’s time for the next replacement and we’ll hope for the best.

As I understand the arrangement, she must get all the consumables (masks, hoses, filters, tanks) from Lincare for five years from the date of the original prescription. After that, she can order supplies from elsewhere, although that seller must have a new prescription.

Basically, Lincare gets five years of guaranteed business and, like the phone company of old, they don’t care about you because they don’t have to.

So: they win.

2026-01-29

Ice Flow

Spotted at the local library:

Putting the downspout inside the building probably made architectural sense, but I’d much rather have that pipe on the outside of the wall where a leak won’t be so expensive.

It hasn’t leaked yet, but in a few months I won’t be surprised to learn my tax dollars were hard at work fixing the ensuing water damage.

Taken at maximum zoom through a grubby windshield, so the picture quality isn’t up to contemporary standards.

2026-01-28

Plywood Coaster Warpage

This is what happens to an uncoated plywood coaster with fairly deep laser engraving after about half a year of use:

Warped plywood coaster - front — Warped plywood coaster – front

The poor thing went all potato chip:

Warped plywood coaster - side — Warped plywood coaster – side

I swapped it for one with polyurethane sealant, much like those fancier coasters with the same layout, and we’ll see if it survives longer …

2026-01-27

Snow Day

Today looks like a good day to fire up the snowblower and clear the driveway:

One of the bolts holding the muffler on the engine worked its way past its rebuilt locking plate and will require attention before getting out there.

Fortunately, it looks like a good day for shop projects …

2026-01-26

Olive Oil Bottle Cap Covers

We buy olive oil in large bottles, then fill smaller bottles for easier handling. The caps on those bottles were never meant to last as long as we keep them and the thin, deeply drawn aluminum tends to crack after a while.

So I conjured a cap cover from the vasty digital deep:

Olive Oil Cap - solid model — Olive Oil Cap – solid model

Which looks exactly like you’d expect when printed in black PETG:

Olive oil bottle cap - details — Olive oil bottle cap – details

You can see the raggedy edge of the original cap just inside the cover’s rim. A snippet of double-sided tape holds the cover in place, after de-oiling the cap with alcohol.

Having gotten one to fit, I made enough for All The Bottles:

Olive oil bottle cap - installed — Olive oil bottle cap – installed

Only two of those see regular service: one in use and another filled when the first is nearly empty. The remaining pair huddle in the back of the shelf against future need.

The OpenSCAD source code produces those fancy knurls with BOSL2’s textured cyl() :

// Olive Oil Overcap
// Ed Nisley - KE4ZNU
// 2026-01-17

include <BOSL2/std.scad>

/* [Hidden] */

HoleWindage = 0.2;
Protrusion = 0.1;
NumSides = 5*3*4;

$fn=NumSides;

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

WallThick = 1.0;
BaseThick = 2.0;

CapOD = 36.0;

CoverOA = [CapOD,CapOD + 2*WallThick,20.0 + BaseThick];

//----------
// Build it

  render()
    difference() {
      cyl(BaseThick,d=CoverOA[OD],chamfer1=1.0,anchor=BOTTOM) position(TOP)
        cyl(CoverOA[LENGTH] - BaseThick,d=CoverOA[OD],
            texture="trunc_pyramids",tex_size=[2,6], style="convex",
            anchor=BOTTOM);
      up(BaseThick)
        cyl(CoverOA[LENGTH],d=CoverOA[ID],anchor=BOTTOM);
    }

2026-01-20

Translucent Night Light Light Guide

Our house came with several single-LED night lights featuring a transparent light guide / reflector:

Nightlight light guide - original — Nightlight light guide – original

The plate had snapped off one of them and, being me, I wondered if I could replace it with something similar.

Years passed.

Obviously, this must be made from a transparent substance, which 3D printed things are not, but after some fiddling with parameters I thought the result might be informative.

The guide plate is a section of a spherical surface, here approximated by a BOSL2 spheroid():

Nightlight light guide - view side - solid model — Nightlight light guide – view side – solid model

The original is 3 mm thick, but 2 mm worked out better for my purposes by reducing the amount of infill:

Nightlight light guide - wall side - solid model — Nightlight light guide – wall side – solid model

The intricate base latches into the lamp’s plastic case:

Nightlight light guide - base - solid model — Nightlight light guide – base – solid model

The result is, at best, translucent, because it’s definitely not transparent:

Nightlight light guide - translucent vs transparent — Nightlight light guide – translucent vs transparent

The zigzag pattern seems to come from the icosohedral approximation to the sphere, because it follows the surface tesselation.

Getting the base shape right required several iterations, each printed with the model cut off just above the bottom of the guide plate:

Nightlight light guide - test pieces — Nightlight light guide – test pieces

The first two attempts needed attention from a flush cutting pliers before fitting into the case, but they don’t call it rapid prototyping for nothin’.

The original and replacement plugged into an outlet strip:

Nightlight light guide - original vs printed on outlet strip — Nightlight light guide – original vs printed on outlet strip

While you can see the vague outline of the strip behind the printed light guide, it’s definitely lacking in detail:

Nightlight light guide - outlet strip detail — Nightlight light guide – outlet strip detail

The striations throw more light into the room than the original:

Nightlight light guide - printed — Nightlight light guide – printed

Fiddling with the 3D printing parameters might make it more transparent, but it’s going back into the box it came from after giving me a better idea of which parameters to tweak the next time around.

The OpenSCAD source code as a GitHub Gist:

	// Nightlight light guide
	// Ed Nisley – KE4ZNU
	// 2026-01-13

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build,Plate,Base,Pipe]

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 1034;

	$fn=NumSides;

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

	function ChordRadius(m,c) = (m^2 + (c^2)/4) / (2*m);

	PlateThick = 2.0;
	PlateOA = [60.0,50.0,PlateThick];
	PlateRound = 5.0;
	PlateTaper = 1.0;
	PlateAngle = atan(-2/60); // original plate angle, far end closer to wall

	PlateM = 2.4;
	PlateRadius = ChordRadius(PlateM,PlateOA.x); // light guide plate
	echo(PlateRadius=PlateRadius);

	WallThick = 2.0;

	MountOA = [23.4,17.0,5.5];
	MountRadius = ChordRadius(4.3,MountOA.x); // base arc in housing
	echo(MountRadius=MountRadius);

	PipeThick = 5.0;

	//———-
	// Define shapes

	// Oddly intricate base fitting into housing
	// Replete with magic numbers

	module Base() {

	difference() {
	union() {
	intersection() {
	cuboid([MountOA.x,MountOA.y,5.5],anchor=BOTTOM);
	back(6.5)
	tube(MountOA.z,or=MountRadius,wall=1.5,anchor=BOTTOM+BACK);
	}

	for (i=[-1,1])
	right(i*18.5/2)
	back(11.5)
	cuboid([1.8,8.0,MountOA.z],anchor=BOTTOM+BACK);

	for (i=[-1,1])
	right(i*22.0/2)
	cuboid([1.4,2.0,MountOA.z],anchor=BOTTOM+FRONT);

	fwd(5.0)
	cuboid([11.0,10.5,MountOA.z],anchor=BOTTOM+FRONT);
	}

	down(Protrusion)
	for (j=[-1,1])
	fwd(j*(1.5 + 10.0)/2)
	cuboid([7.0,10.0,MountOA.z + 2*Protrusion],anchor=BOTTOM);

	up(3.1)
	back(7.5)
	cuboid([MountOA.x,25.0,MountOA.z],anchor=BOTTOM+FRONT);
	}
	}

	// Light guide plate

	module Plate() {

	xrot(PlateAngle)
	zrot(90) yrot(90)
	left(PlateOA.x/2)
	down(PlateM + PlateThick/2)
	intersection() {
	up(PlateRadius)
	difference() {
	spheroid(PlateRadius,style="icosa");
	spheroid(PlateRadius – PlateThick,style="icosa");
	}
	cuboid(PlateOA + [0,0,2*PlateThick],rounding=PlateRound,edges="Z",anchor=BOTTOM);
	}

	}

	// Light pipe between base & plate
	// Magic numbers to fit case opening

	module Pipe() {

	difference() {
	intersection() {
	fwd(3.0/2 – 0.2)
	cuboid([MountOA.x,MountOA.y,PipeThick],rounding=0.5,edges="Z",anchor=BOTTOM+FRONT);
	back(6.5)
	cyl(MountOA.z,r=MountRadius,anchor=BOTTOM+BACK);
	}

	down(Protrusion)
	back((1.5 + 10.0)/2)
	cuboid([7.0,10.0,1.0 + Protrusion],anchor=BOTTOM);

	}

	}

	module Assembly() {

	Base();

	up(MountOA.z)
	Pipe();

	up(MountOA.z + PipeThick)
	Plate();
	}


	//———-
	// Build things

	if (Layout == "Base")
	Base();

	if (Layout == "Plate")
	Plate();

	if (Layout == "Pipe")
	Pipe();

	if (Layout == "Show" \|\| Layout == "Build")
	Assembly();

view raw Nightlight Light Guide.scad hosted with ❤ by GitHub

2026-01-16

Translucent Soap Dishes

A SquidWrench meeting discussion about printing transparent objects prompted me to conjure a soap dish from the vasty digital deep:

Shower Soap Dish - solid model — Shower Soap Dish – solid model

They’re all done in “natural” PETG with sufficient variations in speed, temperature, extrusion multiplier, and fill pattern to stock the shower & tub:

The single-thread sidewalls came out reasonably translucent in all the variations, but the baseplate remained stubbornly white-ish, even at 20 mm/s and 250 °C with 100% infill. The seams where the extruder retracts and lifts to the next layer remain conspicuous, with a scarf joint forming the white slab in the left-rear dish.

Quite a while ago, I’d considered making soap dishes with shattered-glass bottoms, but came to my senses. These have some key advantages:

Exactly the right size for narrow shower shelves
Light enough to not damage anything when it inevitably falls off
Reasonably unbreakable when that happens
Easily replaced

They’re also test pieces for the whole transparency thing, so it’s all good.

The OpenSCAD source code as a GitHub Gist:

	// Shower soap dish
	// Ed Nisley – KE4ZNU
	// 2026-01-13

	include <BOSL2/std.scad>

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 334;

	$fn=NumSides;

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

	WallThick = 0.6;
	BaseThick = 2.0;

	//DishOA = [80.0,40.0,20.0]; // standing used Dove
	DishOA = [90.0,50.0,30.0]; // standing Dove
	//DishOA = [100.0,65.0,30.0]; // half-bar

	DishTaper = [10.0,10.0];
	CornerRadius = 15.0;

	DrainOA = [10.0,DishOA.y,3.0];
	DrainOC = DishOA.x/3;

	//———-
	// Build it

	difference() {
	union() {
	linear_extrude(BaseThick)
	rect([DishOA.x,DishOA.y] – DishTaper,rounding=CornerRadius);

	rect_tube(DishOA.z,wall=WallThick,
	size1=[DishOA.x,DishOA.y] – DishTaper,size2=[DishOA.x,DishOA.y],
	rounding=CornerRadius,anchor=BOTTOM);
	}

	for (j=[-1,1])
	right(j*DrainOC/2)
	up(BaseThick)
	cuboid(DrainOA,rounding=1.0,anchor=BOTTOM+BACK);
	}

view raw Shower Soap Dish.scad hosted with ❤ by GitHub

2026-01-15