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

Doorbell Button Skulls
With only days to spare, I decorated the doorbell button:

Doorbell button skulls – installed

Yeah, I jammed Sharpies in the eye sockets, but they look exactly the way they should. The middle skull is in the middle of the actuator in the hope that’s where it’ll get pushed.

The solid model comes directly from the seasonally appropriate teapot lid handle with a rectangle to suit the doorbell button actuator:

Doorbell Button Skulls – solid model

Perforce, the OpenSCAD code has eyeballometric magic numbers:
```
// Doorbell Button Enhancement
// Ed Nisley - KE4ZNU
// 2024-10-28

Button = [5.0,13.0,40.0];    // button width, boss depth, button height

union() {
    rotate([0,0,65])
    translate([-121,-105])      // totally eyeballometric
        import("stackofskulls - 50mm.obj",convexity=10);

        translate([0,Button.y/2,Button.z/2])
            cube(Button,center=true);
}
```
The rectangular slab goes all the way down to the platform because I couldn’t be bothered with support or a little wedge.

I’m sure it will survive exactly as long as it must.

Dunno how many little ones will venture up the driveway, though:

Halloween mailbox decorations
2024-10-31
Cart Coin Handle vs. Reality

This failed pretty much the way I expected:

Cart Coin – broken handle

The “carbon fiber” part of PETG-CF consists of very very short fibers, unlike the longer fibers in real carbon fiber materials, so the strength is nowhere near what you might expect from the marketing. I knew this going in and the break wasn’t surprising.

Round cart coins continue to work exactly like US quarters.

2024-10-29
Humidifier Lid Hinges
The humidifier that Came With The House™ had a lid with two broken plastic hinges that I figured I could never replace, but while cleaning out the fuzz for the upcoming season I found one missing piece stuck inside the lid. Given a hint, I glued it back in place:

Humidifier Hinge – outlined

There’s a strip of duct tape around the outside holding the fragment in place while the adhesive cured.

A manual curve fit to the image in Inkscape produced the red outline, which gets saved as a plain SVG and fed into OpenSCAD to create a solid model:

Humidifier Hinge – solid model

The cylinder doesn’t exactly fit the end of the hinge, but it’s close enough. The straightforward OpenSCAD code making that happen:
```
// Humidfier Hinge Replacement
// Ed Nisley KE4ZNU
// 2024-10-20

HingeThick = 10.0;
PinLength = 10.0;

ScrewOD = 2.0;

NumSides = 2*3*4;
Protrusion = 0.1;

difference() {
    union() {
        translate([0,0,HingeThick])
            cylinder(d=6.0,h=PinLength,$fn=NumSides);

        linear_extrude(height=10.0,convexity=5)
            translate([-3.1,-8.0])
                import("Humidifier Hinge - ouline.svg");
    }

    cylinder(d=ScrewOD,h=4*(HingeThick + PinLength),center=true,$fn=8);
}
```
The pin has a hole for a M2 screw, but contemplation of the broken pieces suggested the pin wasn’t the weakest link, which later experience confirmed.

Figuring I’d need only one hinge, I made a spare for fitting:

Humidifier hinge – on platform

The unmodified part fit just about perfectly, whereupon a completely ad-hoc fixture involving a pair of laser-cut MDF slabs, a craft stick epoxy mixer, and more duct tape held it in place while the adhesive cured:

Humidifier hinge – fixturing

The hinge pin turned out to be half a millimeter too long, which is easily fixed, and it worked fine:

Humidifier hinge – installed

That’s more duct tape wrapped around the perimeter to hold the pieces in place, should it break again.

Which, I regret to report, occurred on the way up the stairs from the Basement Shop™ when the lid slipped from my grasp, fell away from the rest of the humidifer’s top panel, and jammed open:

Humidifier hinge – break

The PETG-CF part held together, the adhesive remained bonded to both pieces, but the original plastic fractured just below the joint. A closer look from the other side shows the break:

Humidifier hinge – break detail

The other hinge broke about where it did before.

So the humidifier remains in service with the lid in status quo ante and a small bag inside holding the fragments for the next return to the shop.

Drat!
2024-10-28
Worst Deck Staining Job Ever

This looks about as awful as I expected:

Worst deck staining job ever

The previous owners replaced the deck two years ago, but the contractor installed more than half the planks with the grain cupped upward. The job was so bad the contractor replaced the most egregiously warped planks (over by the door and out of sight on the right) under warranty, but left all the other mis-oriented planks in place, presumably because they weren’t that bad yet.

The bare wood must age for a while before staining, so the shelf of painting supplies held a year-old gallon can as a reminder, with about two inches of stain / preservative in the bottom. I applied it to the “new” planks with pleasing results that absolutely do not match the rest of the weathered wood. With nothing to lose and plenty to gain, I applied the rest of the potion to the worst of the upside-down planks, producing the egregiously bad result you see above.

Given how the stain weathered to oblivion over the course of the last year, I expect all those planks will become roughly the same shade of ugly by next summer, when I might possibly be motivated to slather another gallon over the deck.

A friend observes: Houses are trouble.

2024-10-25
Dancing With The Stars Quilt: First Wash

Mary recently finished a multi-year quilt project:

Dancine With The Stars quilt – detail

The overall pattern is “Dancing With The Stars” and it involves more intensive detail work than I have ever deployed on anything I’ve ever done:

Mary with quilt on ping-pong table

Washing the quilt required a generous handful of Color Catchers to prevent the bold colors from bleeding into the lighter fabrics:

Dancing With The Stars quilt – color catchers

The sheets on the left came from the wash and the ones on the right came from a separate rinse cycle. We didn’t expect the “average” color to be brown, but there it is. We were both mightily relieved when they performed as expected!

Now, to send it away …

2024-10-23
EBL Bucked Lithium AA and AAA Cells

A new kitchen scale eats a quartet of AAA alkaline cells every month, so a set of bucked lithium AAA cells make sense:

EBL AAA first charge – 2024-09-11

The cells claim 1200 mA·hr capacity, because it looks much more impressive than 1.2 A·hr, and deliver 900 mA·hr at 500 mA, likely higher than the scale’s actual load current.

The old Sony DSC-H5 works well with the light box and gets a pair of bucked lithium AA cells to replace the tired Eneloops:

EBL AA first charge – 2024-10-17

They claim 3000 mA·hr and deliver 2.5 A·hr at 500 mA: nearly perfect, considering some of the junk I’ve gotten over the years.

Now, to see how they behave in real life …

2024-10-22
Seasonally Appropriate Teapot Knob
Long years ago, the Bakelite (or some such) lid on our rarely used teapot disintegrated, whereupon I replaced it with an aluminum sheet and metal knob. Admittedly, a metal knob was not the brightest idea I ever had, but it sufficed for a few uses over the intervening decades.

Mary hosted this month’s quilting bee and, after having someone else bring a larger teapot for the occasion, suggested I Make. A. Better. Knob. After a bit of searching, this statue seemed appropriate for the season:

Skull teapot knob

It’s printed with PETG filament that should easily withstand the no-more-than-boiling-water temperatures found atop a teapot.

I imported the original model into PrusaSlicer, shrank it to 50 mm tall and simplified the mesh, exported it as an OBJ file, imported it into OpenSCAD, mashed it together with a 1/4-20 threaded_nut from BOSL2, added the finger protector, and got a suitable model:

Teapot Knob – solid model bottom view

The as-printed threads were a bit snug with $slop=0, but running the screw in with a dot of silicone grease to ease the way worked fine.

I should rebuild the whole lid in PETG-CF sometime.

The OpenSCAD code stitches the parts together:
```
// Teapot Knob
// Ed Nisley - KE4ZNU
// 2024-10-11

include <BOSL2/std.scad>
include <BOSL2/threading.scad>

StackHeight = 50.0;
ThreadLength = 25.0;
HeatbreakOD = 40.0;
HeatbreakThick = 3.0;

    intersection() {
        union() {
            cylinder(d=HeatbreakOD,h=HeatbreakThick,$fn=2*4*9);
            up(HeatbreakThick)
                translate([-121,-105])      // totally eyeballometric
                    import("stackofskulls - 50mm.obj",convexity=10);
        }

        union() {
            threaded_nut(100,INCH/4,ThreadLength,INCH/20,        // flat size, root dia, height, pitch
                                     bevel=false,ibevel=false,anchor=BOTTOM);
            up(ThreadLength)
                cylinder(d=100,h=StackHeight);
        }
    }
```
2024-10-16