Tag: Improvements

Making the world a better place, one piece at a time

Marquetry Test Piece

Based on several examples from the LightBurn forum ~~which I cannot find~~, this emerged:

Marquetry test – finished

It’s ordinary laser-grade 3 mm plywood with another wood inlay, sanded flat and covered with polyurethane sealer.

The key attraction: not fiddling with tiny veneer bits.

Cut the recesses in one pass with enough energy to make them at least as deep as the veneer thickness:

Marquetry test – plywood cutting

Press the veneer onto aluminum tape, taking care to avoid wrinkles and folds, and cut away everything that doesn’t go into those recesses:

Marquetry test – veneer cutting

Which looks gnarly when you’re done:

Marquetry test – veneer on tape

I cut the aluminum tape to fit within the corner targets around the plywood layout, thus ~~simplifying~~ making possible aligning the positive veneer shapes with the negative plywood shapes while being unable to see either of them.

Slather wood glue over the plywood, make sure even the tiniest recesses are filled, align the aluminum, clamp the two firmly together, wait for a few days while the glue cures in that airless space, then peel off the aluminum:

Marquetry test – peeled

Which looked so awful I thought that was a disaster, not least because the veneer stood proud of the plywood, so it remained on the back of the bench for far too long.

Eventually, having deployed the sander for another project, I sanded the veneer flush with the plywood to reveal the nearly perfect results in the lead picture. There’s a bit of smoke stain left in the grain, but the tiniest recesses have at least some veneer fill and the surface is entirely smooth.

The overlaid circles worked out:

Marquetry test – detail 1

The darkest block and the smaller lines are badly smoke-stained veneer, as they have wood grain visible under magnification. I think those may not have fully entered their recesses and we’re seeing a very thin veneer layer soaked with soot-filled wood glue.

Another view:

Marquetry test – detail 2

The checkerboard squares worked well;

Marquetry test – squares 1

To my astonishment, even the 0.5 mm squares have some veneer inside, as do the 0.5×1.0 mm rectangles on the left:

Marquetry test – squares 2

Not knowing any better, there’s no kerf offset on any of the figures and they’re separated by about the 0.2 mm width of the focused spot.

Aligning the veneer to the recesses was tricky and I was not at all sure it had happened. I think larger shapes would be much easier and might give off a confirming squish as they meet their sockets.

Gotta try that again without the benefit of beginner’s luck.

2025-11-26
Large Smashed Glass Coaster
Those of long memory will recall our vermiculture setup in the basement that turns kitchen scraps into plant food. We accumulate scraps in plastic milk jugs, which jugs get recycled after they become grody.

I finally made a decorative coaster to keep the sometimes-wet jug off the counter:

Printed Fragment Coaster 165mm – in use

This used several of the larger smashed glass fragments from the collection:

Fragments 165mm square – scan sample

They all fit inside a 165 mm square, with the conformal perimeter disguising the outline:

Printed Fragment Coaster 165mm – overview

I printed the frame with the same blue PETG-CF that leaked epoxy the last time around. Using the correct filament setting (Extrusion Multiplier = 1.0) produced an epoxy-tight frame:

Printed Fragment Coaster 165mm – epoxy filling

The overall process:
- Run a bead of epoxy around the edge of each recess
- Fill in the center with a thin layer
- Squish the metallized paper reflector in place starting from one end to ease the bubbles out
- Cover the reflector with another layer of epoxy
- Lay the glass fragment down starting at one end
- Press gently down to get all the bubbles out
- Cover the glass with more epoxy
I dripped enough epoxy on each fragment to form a meniscus without having it go over the rim:

Printed Fragment Coaster 165mm – epoxy meniscus

The Basement Shop temperature is just over 60 °F, so I put a heating pad in a huge ziplock bag, laid an aluminum sheet atop it as a heat spreader, put some waxed paper on the aluminum just in case, then did the filling described above:

Printed Fragment Coaster 165mm – warming setup

A cardboard box on top helped the heating pad keep the coaster at a uniform 85 °F, slightly warmer than the epoxy instructions recommend, but it cured overnight with a wonderfully shiny surface.

Now that I have the process down, making glittery coasters is surprisingly easy.
2025-11-25
PolyDryer Humidity: White PETG

The white PETG filament started out at 39 %RH and 50 g of silica gel dragged it down to 23 %RH after a three days: still unusually high.

The beads weighed 54.6 g, a weight gain of 9 %, which is about as much as they’ll take. I replaced them with 50 g of new-from-the-bottle beads and the meter dropped to 14 %RH overnight.

Running the tiny fan for another day made no difference:

Polydryer Box desiccant tray – fan

Thereby confirming my suspicion that air circulation inside the box isn’t nearly as much of a problem as I expected.

So filament need not arrive bone-dry and, with enough surface area exposed to the air, silica gel beads can adsorb their limit of water vapor in a day or two.

2025-11-24

Bird Feeder Tray Mount

The mixed flock attending the bird feeder in the back yard scatters enough seeds to attract the deer, so I added a tray underneath to catch the overspray:

Well, two trays, because it took a couple of iterations to make the solid model match reality:

Bird Feeder Tray Mount - show layout — Bird Feeder Tray Mount – show layout

The n-1 iteration was Close Enough™ and two trays are obviously better than one.

The “trays” are stray lids from the six gallon buckets we use for many purposes, including root-cellaring the vegetable garden harvest. The lid’s solid model was straightforward:

Bird Feeder Tray Mount - lid model — Bird Feeder Tray Mount – lid model

Removing the lid from a solid block produces the most complex part of the mount:

Bird Feeder Tray Mount - mount layout — Bird Feeder Tray Mount – mount layout

An aluminum plate on the outside (the gray slab in the overall view above) distributes the strain from the two M6 screws across the block.

A smaller block on the inside of the lid has a pair of square nuts:

Bird Feeder Tray Mount - segment layout — Bird Feeder Tray Mount – segment layout

All three parts build from their flattest side:

Bird Feeder Tray Mount - build layout — Bird Feeder Tray Mount – build layout

The downward facing clamp arch in the main block didn’t need support, but the square nut sockets in the segment definitely came out better with little support blocks inside; PrusaSlicer does a good job with most support structures.

The n-1 iteration used M6 rivnuts that were slightly too long after making the lid model match reality, so I switched to square nuts. The OpenSCAD code calculates the segment block length to match the actual screws, but 75 mm M6 screws and square nuts are barely long enough.

I clamped the outer block to the lid as a drill guide for the first hole, then pinned the block with a screw to ensure it didn’t slip while drilling the second hole:

Bird Feeder Tray Mount - drilling setup — Bird Feeder Tray Mount – drilling setup

Those were freehanded in the drill press at low speed with serious concentration; some things you just gotta do that way.

The mixed flock overwhelmingly approves the trays, to the extent a dozen birds clamor to use them: definitely a crowd-pleaser!

I’m certain you can buy pole-mounted trays, but what’s the fun in that?

The OpenSCAD source code as a GitHub Gist:

	// Bird feeder tray mount
	// Ed Nisley – KE4ZNU
	// 2025-11-06

	include <BOSL2/std.scad>

	Layout = "Show"; // [Build,Show,Lid,Mount,Segment,Nut]

	/* [Hidden] */

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

	HoleWindage = [0.2,0.2,0.2];
	Protrusion = 0.1;

	NumRibs = 12; // stiffening ribs
	NumSides = 8*NumRibs;

	$fn=NumSides;

	Gap = 5.0;

	WallThick = 9.0; // robust walls
	Kerf = 1.0; // clamp cut
	TapeThick = 0.5; // wrap around pole

	LidOD = 12; // main diameter in inches

	PoleOD = 1*INCH;

	PlateThick = 2.0; // backing plate for clamp

	Screw = [6.0,12.0,6.0]; // thread OD, washerOD, head
	ScrewLength = 75.0;

	ScrewOC = 60.0; // chosen to clear stiffening ribs in lid

	LidLayers = [ // bottom to top, ID = 0 means solid disk, LENGTH = exterior measurement
	[0,(LidOD-2(3/8))INCH,Protrusion], // 0 – below zero to prevent Z fighting
	[0,(LidOD-2(3/8))INCH,(3/8)*INCH], // 1 – base inside bucket
	[0,(LidOD+2(1/8))INCH,(1/8)*INCH], // 2 – flange
	[(LidOD-2(1/2))INCH,LidODINCH,(7/8)INCH], // 3 – sealing ring
	];

	LidOAH = LidLayers[1][LENGTH] + LidLayers[2][LENGTH] + LidLayers[3][LENGTH];
	LidTopDepth = (3/4)*INCH; // from highest part of interior

	MountBlockWidth = ScrewOC + 2*WallThick;

	BaseSagitta = LidLayers[1][OD]/2 – sqrt((LidLayers[1][OD]/2)^2 – (MountBlockWidth^2)/4);
	echo(BaseSagitta=BaseSagitta);

	PoleOffset = BaseSagitta + ((LidLayers[2][OD] – LidLayers[1][OD])/2) + WallThick + PoleOD/2;

	MountBlock = [PoleOffset + PoleOD/2 + WallThick – PlateThick,MountBlockWidth,LidOAH];
	echo(MountBlock=MountBlock);

	SegBlockOffset = ScrewLength – MountBlock.x – PlateThick; // assumes recessed
	SegmentBlock = [2*SegBlockOffset,MountBlock.y,LidTopDepth];

	Rib = [2*6.0,5.0,LidTopDepth]; // lid stiffening ribs
	RibAlign = 0 * 180/NumRibs; // position ribs wrt mount

	EdgeRadius = 3.0;

	//—–
	// Rivnut
	// The model collects all the magic numbers right here

	/*
	RivnutOAL = 15.0;

	module Rivnut() {

	union() {
	cyl(1.6,d=13.0,circum=true,anchor=BOTTOM);
	cyl(RivnutOAL,d=9.0,circum=true,anchor=BOTTOM);
	}

	}

	*/

	//—–
	// Square nut
	// The model collects all the magic numbers right here

	NutOAL = 5.0;

	module SquareNut() {

	cuboid([10.0,10.0,5.0],anchor=BOTTOM);

	}
	//—–
	// Bucket lid
	// Centered at XY=0, Z=0 at top of exterior flange

	module BucketLid(Interior=true,Expand=false) {

	render()
	union() {
	down(LidLayers[2][LENGTH])
	cyl(LidLayers[1][LENGTH],d=LidLayers[1][OD],anchor=TOP);
	cyl(LidLayers[2][LENGTH],d=LidLayers[2][OD],anchor=TOP);
	if (Interior) {
	if (false)
	down(Expand ? Protrusion : 0)
	tube(LidLayers[3][LENGTH] + (Expand ? 2*Protrusion : 0),
	id=LidLayers[3][ID],od=(Expand ? 2 : 1)*LidLayers[3][OD],anchor=BOTTOM);
	else
	difference() {
	cyl(LidLayers[3][LENGTH] + (Expand ? 2*Protrusion : 0),
	d=(Expand ? 2 : 1)*LidLayers[3][OD],anchor=BOTTOM);
	up(LidLayers[3][LENGTH] – LidTopDepth)
	cyl(LidTopDepth + (Expand ? 2*Protrusion : 0),
	d=LidLayers[3][ID],anchor=BOTTOM);
	}
	up(LidLayers[3][LENGTH] – LidTopDepth)
	for (i=[0:(NumRibs – 1)])
	zrot(i*360/NumRibs + RibAlign)
	right(LidLayers[3][ID]/2)
	cuboid(Rib,anchor=BOTTOM,rounding=1,edges="Z");
	}
	else
	down(Expand ? Protrusion : 0)
	cyl(LidLayers[3][LENGTH] + (Expand ? 2*Protrusion : 0),
	d=(Expand ? 2 : 1)*LidLayers[3][OD],anchor=BOTTOM);
	}
	}

	// Mount clamp

	module Mount() {
	render()
	difference() {
	cuboid(MountBlock,anchor=BOTTOM+LEFT,rounding=EdgeRadius,edges="X");
	left(LidLayers[1][OD]/2 – BaseSagitta)
	up(LidLayers[1][LENGTH] + LidLayers[2][LENGTH])
	BucketLid(Interior=false);
	right(PoleOffset) {
	cyl(3MountBlock.z,d=(PoleOD + HoleWindage.x + 2TapeThick),circum=true,anchor=CENTER);
	cuboid([Kerf,2MountBlock.y,3MountBlock.z]);
	}
	if (false)
	right(MountBlock.x – PlateThick)
	cuboid(3*[PlateThick,MountBlock.y,MountBlock.z],anchor=LEFT);
	up(LidOAH – LidLayers[3][LENGTH]/2)
	for (j=[-1,1])
	fwd(j*ScrewOC/2) {
	cyl(ScrewLength,d=Screw[ID] + HoleWindage.x,circum=true,orient=RIGHT,anchor=BOTTOM,$fn=6,spin=180/6);
	if (false)
	right(MountBlock.x + Protrusion)
	cyl(Screw[LENGTH] + Protrusion,d=Screw[OD] + HoleWindage.x,circum=true,
	orient=LEFT,anchor=BOTTOM,$fn=12,spin=180/12);
	}
	}
	}

	// Nut block segment inside lid

	module NutSegment() {

	render()
	difference() {
	cuboid(SegmentBlock,anchor=BOTTOM,rounding=EdgeRadius,edges="X");
	down(LidLayers[3][LENGTH] – LidTopDepth)
	left(LidLayers[1][OD]/2 – BaseSagitta)
	BucketLid(Interior=true,Expand=true);
	up(LidTopDepth – LidLayers[3][LENGTH]/2)
	for (j=[-1,1])
	fwd(j*ScrewOC/2) {
	left(SegmentBlock.x/2)
	cyl(ScrewLength,d=Screw[ID],circum=true,anchor=BOTTOM,$fn=6,spin=180/6,orient=RIGHT);
	left(SegmentBlock.x/2)
	yrot(90)
	SquareNut();
	}
	}

	}

	//—–
	// Build things

	if (Layout == "Lid")
	BucketLid();

	if (Layout == "Mount")
	Mount();

	if (Layout == "Segment")
	NutSegment();

	if (Layout == "Nut")
	Rivnut();

	if (Layout == "Show") {
	down(LidLayers[1][LENGTH] + LidLayers[2][LENGTH]) {
	Mount();
	color("Orange",0.5)
	up(LidOAH – LidLayers[3][LENGTH]/2)
	right(MountBlock.x + PlateThick)
	for (j=[-1,1])
	fwd(j*ScrewOC/2)
	cyl(ScrewLength,d=Screw[ID],circum=true,orient=LEFT,anchor=BOTTOM);
	}
	up(LidLayers[3][LENGTH] – LidTopDepth)
	NutSegment();

	color("Gray",0.4)
	right(PoleOffset)
	cylinder(3*MountBlock.z,d=(PoleOD),anchor=CENTER);
	color("Gray",0.4)
	left(LidLayers[1][OD]/2 – BaseSagitta)
	BucketLid();
	color("White",0.7)
	down(LidLayers[1][LENGTH] + LidLayers[2][LENGTH])
	right(MountBlock.x + 2*PlateThick)
	difference() {
	cuboid([PlateThick,MountBlock.y,MountBlock.z],anchor=BOTTOM+LEFT,rounding=EdgeRadius,edges="X");
	up(LidOAH – LidLayers[3][LENGTH]/2)
	for (j=[-1,1])
	fwd(j*ScrewOC/2)
	cyl(ScrewLength,d=Screw[ID],circum=true,orient=RIGHT,anchor=CENTER);
	}
	}

	if (Layout == "Build") {
	render()
	union() {
	difference() {
	left(MountBlock.z + Gap/2)
	up(PoleOffset – Kerf/2)
	yrot(90)
	Mount();
	cuboid([3MountBlock.z,2MountBlock.y,3*MountBlock.x],anchor=TOP);
	}
	render()
	right(Gap/2)
	intersection() {
	up(MountBlock.x)
	yrot(90)
	Mount();
	up(MountBlock.x – PoleOffset)
	right(MountBlock.z/2)
	cuboid([2MountBlock.z,2MountBlock.y,MountBlock.x],anchor=TOP);
	}
	right(2*MountBlock.z – BaseSagitta)
	up(SegmentBlock.x/2)
	yrot(-90)
	NutSegment();
	}
	}

view raw Bird Feeder Tray Mount.scad hosted with ❤ by GitHub

2025-11-19

AC Power / Energy Meter

A surprisingly competent AC power-line voltage / current / energy / power meter fits neatly into a mud ring atop a 4×4 inch square electrical box:

AC Power Meter – assembled

The inside view shows the wiring, such as it is:

AC Power Meter – interior

The square black block is the split-core current transformer around the hot line wire, which sticks up just enough in any orientation to require an extension ring, thus a second trip to the Big Box store.

The mud ring has two tabs with threaded screw holes for the device (switch / GFCI / whatever): grab those with a Vise-Grip, flex until they break off, then file down the stub.

Generous globs of hot-melt glue secure the meter in the mud ring. I added a strip of duct tape under the connections in the hope it might avert disaster should either of the AC wires come loose, but my real hope is in the safety ground to the metal box.

The line cord comes from the Box o’ IEC cords, minus its IEC connector, plus the bright yellow USA-ian connector.

Yes, the three metal box pieces and the Leviton connector cost far more than the meter.

Not to code, but good enough for my purposes.

2025-11-18
PolyDryer Box Desiccant Tray

Having used desiccant in tea bags inside the PolyDryer boxes with some success, I wanted to see what happens with more exposed surface area:

Polydryer Box desiccant tray – installed

The tray (jawbreaker boxes.py URL) is 2 mm chipboard with a quartet of additional notches fitting the protrusions in the bottom of the Polydryer box:

Polydryer Box desiccant tray – assembly

Although you’ll find plenty of printed trays, many with ingenious perforated lids, this was quick & easy:

Polydryer Box desiccant tray – cutting

They’re painfully prone to dumping their contents, despite the dividers which are intended to dissuade the beads from taking collective action and surging over the slightly higher outer walls. Fortunately, the dump occurs inside a sealed box and is entirely survivable.

Distributing 25 g of silica gel neatly fills the sections:

Polydryer Box desiccant tray – top view

Now it’s just a matter of time …

2025-11-17
Dryer Vent Filter Snout: TPU Warp

Making the clothes dryer vent filter snout from TPU did not work nearly as well as I expected:

Clothes Dryer Vent Filter Snout – TPU warp

I think that’s the result of applying heat to a slightly compressed rear wall made of bendy plastic.

Making it from much stiffer white PETG required moving the front mounting tabs to the middle to allow enough bendiness to snap them into the vent:

Clothes Dryer Vent Filter Snout – slicer

Although both pieces barely fit on the MK4’s platform, I made the upper ring first to verify the fit:

Clothes Dryer Vent Filter Snout – slicer

If I ever make another, it’ll print as a single top-side-down unit, because the dimensions are now spot on.

From outside, it looks just like the TPU version:

Clothes Dryer Vent Filter Snout – PETG installed

The snood is a cheesecloth tube with shock cord holding it to the snout.

2025-11-14