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

HQ Sixteen: Improved Anchor

The original anchor / weight keeping the HQ Sixteen from rolling away suffered a disastrous fall, so I conjured a much better-looking replacement from the vasty digital deep:

The handle and fancy nut came from the deceased pepper mill, sitting on laser-cut acrylic in a 3D printed base, with a drawer liner disk peeking out from underneath.

The orange disk in the solid model represents the steel slug harvested from the old anchor:

HQ Sixteen Anchor - solid model - Show view — HQ Sixteen Anchor – solid model – Show view

A ring of hot-melt glue under the weight keeps it from rattling around in there, with the snug-fitting central post encouraging good positioning. I made the acrylic lid sit flush with the top of the base by the simple expedient of running another ring of glue around it, plunking the base + weight atop it on a flat surface, then taking a deep breath while the glue solidified. The nut & screw thus compress a solid stack of acrylic + glue + steel + glue + PETG-CF, rather than just parts flying in formation.

The OpenSCAD source code also produces a pair of outlines for laser-cutting the adhesive sheet and acrylic, suitable for export to an SVG file:

HQ Sixteen Anchor - solid model - cuts — HQ Sixteen Anchor – solid model – cuts

They’re offset inward by amounts appropriate for my CO₂ laser:

if (Layout == "Cuts") {
  left(BaseOD/2 + Gap)
    offset(r=-1.0)
      circle(d=BaseOD);
  right(Cap[OD]/2 + Gap)
    offset(r=-0.2/2)
      projection()
        tube(1.0,id=Cap[ID],od=Cap[OD],anchor=BOTTOM);
}

It might be prudent to apply those offsets to the original outlines in LightBurn or whatever you use for lasering.

The OpenSCAD source code as a GitHub Gist:

	// Anchor block for HQ Sixteen
	// Ed Nisley – KE4ZNU
	// 2026-09-29

	include <BOSL2/std.scad>

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

	/* [Hidden] */

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

	Gap = 10.0/2; // build platform minimum spacing
	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 832*4;

	$fn=NumSides;

	// Sizes

	Screw = [5.5,25.5,5.0]; // 10-24 screw + washer holding it together

	Weight = [11.0,80.0,11.5]; // stamped steel slug

	Cap = [26.0,Weight[OD],5.5]; // acrylic disk with handle hole

	BaseFloor = 10.0;
	BaseOD = 90.0; // printed anchor

	Spacing = 25.0; // Show view separation

	//———-
	// Model things

	module Housing() {

	tube(Screw[LENGTH],id=Screw[OD],od=BaseOD,anchor=BOTTOM) position(TOP) {
	tube(Weight[LENGTH],id=Screw[ID],od=Weight[ID],anchor=BOTTOM); // weight bushing
	tube(BaseFloor – Screw[LENGTH],id=Screw[ID],od=BaseOD,anchor=BOTTOM) position(TOP)
	tube(Cap[LENGTH] + Weight[LENGTH],id=Cap[OD],od=BaseOD,anchor=BOTTOM);
	}

	}


	//———-
	// Build things

	if (Layout == "Show") {
	Housing();
	color("Orange",0.7)
	up(BaseFloor + Spacing)
	tube(Weight[LENGTH],id=Weight[ID],od=Weight[OD],anchor=BOTTOM);
	color("Gray",0.8)
	up(BaseFloor + 2*Weight[LENGTH] + Spacing)
	tube(Cap[LENGTH],id=Cap[ID],od=Cap[OD],anchor=BOTTOM);
	}

	if (Layout == "Cuts") {
	left(BaseOD/2 + Gap)
	offset(r=-1.0)
	circle(d=BaseOD);
	right(Cap[OD]/2 + Gap)
	offset(r=0.2/2)
	projection()
	tube(1.0,id=Cap[ID],od=Cap[OD],anchor=BOTTOM);
	}

	if (Layout == "Build") {
	Housing();
	}

view raw HQ Sixteen Anchor.scad hosted with ❤ by GitHub

2026-10-01

Furnace Zone Shutoff Valve

The upstairs baseboard heating loop collected enough air to frustrate the circulator pump, so I had to close the zone shutoff valve and open the drain valve to flush enough water through the plumbing to get the bubbles out:

Furnace zone drain and shutoff valves

Except: turning that little slotted stem required more torque than I was willing to apply. It may have last been turned a decade ago, during the final furnace servicing on record, but we’ll never know its story.

Furnace zone shutoff valve

Three days of dripping Kroil penetrating oil onto the shutoff valve stems and, just in case, their pipe threads, along with applying the maximum torque I was willing to apply, did the trick, albeit with a distressing amount of squeaking.

A hose from the drain valve to the sump pump pit took care of the outgoing water, flushing proceeded uneventfully, a test firing put hot water into the baseboard, and I could declare victory for the oncoming heating season.

For the record, this was an occasion justifying use of a slotted bit from my Brownell’s Magna-Tip Super Set:

Furnace zone shutoff valve – stem slot

It’s not a perfect fit, but much less sloppy than any other screwdriver in the shop: this is one valve I do not want to abuse.

2026-09-25
Cocoa Powder Shrinkflation

Last year, five pounds of cocoa powder cost $40:

Healthworks Cacao Powder – 2025

This year, five pounds of cocoa powder costs $60:

Healthworks Cacao Powder – 2026

You can reconcile the 1/7.5 reduction in “Serving size” with the 4.7 increase in “Servings per container” by noting the latter matches the 14/3 per-serving weight ratio, not the volume ratio everybody uses. Both bags contain 5 lb of cocoa and have about the same volume; if anything, the newer bag is slightly bulkier.

However, slashing the amount of cocoa in their recipe by a factor of 3 guarantees a truly bland result. Maybe it’s just a missing “b”, a typo that could happen to anyone?

Trust, but verify.

2026-09-24
Shower Squeegee Hanger
Perhaps a 3 mm spacer behind the Command Hook holding the shower squeegee to the stall will let the blade dry out between uses:

Shower Squeegee Hanger – installed

It’s fluorescent green acrylic, because why not?

As with all such things, start with a scan of the base:

Command Hook – base scan

Then:
- Import into LightBurn
- Draw a rectangle fitting the base
- Convert to a path
- Node Edit to put the corner nodes on the perimeter
- Tweak node handles to match curves to perimeter
- Fire The Laser
Contrary to what I expected, the base is not symmetric.

The layout includes another, slightly inset, path to cut a matching shape of 3M 300LSE adhesive to stick the Command Hook onto the acrylic:

Shower Squeegee Hanger – spacer plate

You could stick a rectangle of 300LSE to the acrylic and cut both in one operation, but making the sheet slightly smaller prevents sticky edges, at the cost of aligning the cut sheet on the fly.

The Command Hook’s base is not flat, even after mostly removing the remainder of the previous Hook adhesive, so the 300LSE didn’t bond across the whole thing. If water weakens the bond and it falls off the wall (surely in the middle of the night), the next time around I’ll sand the base flat.
2026-09-22
Printed Fragment Coaster: Delamination and Pinhole

Although “chipboard” is also known as “beer mat”, it’s not intended for long-term use under sweaty mugs. After a few weeks of daily use, this is obviously out of spec:

Printed Fragment Coaster – moisture damage

The aforementioned sweaty mug lifted part of a fragment off the coaster:

Printed Fragment Coaster – delamination

The chipboard is Quickboard from Makerstock, which is basically recycled-fiber chipboard with the advantage of being through-dyed in cheerful colors. It’s described as “2 mm-thick, three-layered board” and it looks like the core delaminated from the bottom layer.

Seeing as how it’s near the end of Sweaty Mug season, I smeared Elmer’s Glue Stick PVA adhesive over the fragment, stuck it back in place, and declared victory.

While doing that, however, I noticed a pinhole:

Printed Fragment Coaster – delamination detail

You may recall the outline came from hand-tracing a fragment of smashed glass in GIMP to get a path, then 3D printing a base to hold it:

Printed Coaster – Set C – oblique

Going back to the original GIMP tracing (storage being cheap, never delete anything), I missed a pixel:

Printed Fragment Set C – GIMP selection – errant pixel

Surely you can see it, particularly because you know exactly where it is. Right?

The (degenerate) path around that pixel becomes a tiny vector in LightBurn:

Printed Fragment Coaster – Set C – orphan vector

It’s easier to see there. Right?

Whereupon LightBurn dutifully punched a pinhole through the chipboard, because that’s what I asked it to do. It also punched that pinhole into the metallized paper reflector under the smashed glass fragment, but I didn’t notice it then, either.

Shrinking the GIMP selection by one pixel width, then growing it by one pixel would eliminate single-pixel selections: just another item on the to-do list while tracing fragments.

Ya learn something new every day around here …

2026-09-21
Another Snowflake Coaster Reaches EOL

Apparently a year in the bathroom under a cup with constant moisture is enough to ruin untreated wood inlaid in an acrylic coaster:

Mildew on wood snowflake coaster

A small 3D printed chipboard fragment coaster now enters service:

Printed Fragment Coaster – small

I recently ran into an interesting chipboard failure suggesting this one won’t last forever, so the clock is ticking.

About which, more later.

2026-09-18
Dog Paw Coaster
Start with a picture of a dog paw:

Dog Paw Coaster – starting picture

Rescale the paw to about 100 mm vertically to properly fit a normal-size glass / tumbler / mug. This may be considerably larger than life, but dog owners always want more dog, so it’ll work.

Generate an outline mask in GIMP:

Dog Paw Coaster – paw mask

Generate another mask for the pads & toenails:

Dog Paw Coaster – pad mask

Convert those into paths, save them as SVG files, and hand them to OpenSCAD:
```
include <BOSL2/std.scad>

/* [Hidden] */

PadThick = 1.2;
BaseThick = 2.0;

RimHeight = 0.4;
RimWidth = 0.8;
RimOffset = 1.0;

Clearance = 0.1;    // embiggen pad recesses

OutlineFN = "Dog Paw - Outline.svg";
PadFN = "Dog Paw - Pads.svg";

union() {


  linear_extrude(h=BaseThick)
    import(OutlineFN);

  color("Green")
    up(BaseThick)
      linear_extrude(h=PadThick)
        difference() {
          import(OutlineFN);
          offset(r=Clearance)
            import(PadFN);
        }

  
}
```
Which will get you a solid model like this:

Dog Paw Coaster – OpenSCAD model

Should you want decorative raised rims around the perimeter and pads:

Dog Paw Coaster – raised rim – OpenSCAD model

Then turn this on:
```
if (false)
  color("Red")
    up(BaseThick + PadThick)
      linear_extrude(h=RimHeight) {
        difference() {
          offset(r=RimOffset + RimWidth)
            import(PadFN);
          offset(r=RimWidth)
            import(PadFN);
        }
        difference() {
          offset(r=-RimOffset)
            import(OutlineFN);
          offset(r=-(RimOffset + RimWidth))
            import(OutlineFN);
        }
      }
```
Run the solid model through PrusaSlicer, send it to the MK4, and, while the printer is buzzing away, run the pads through an online nesting program to see how well that works:

Dog Paw Coaster – Pads nesting – LightBurn layout

While nesting didn’t save much material, it might come in handy for something more intricate and now I’ll be able to find it again.

Then get busy:
- Stick adhesive sheet to the chipboard
- Mirror the pads to cut adhesive side up
- Cut the pads, rescue a toenail from the chip tray
- Import the paw outline SVG
- Offset 0.75 mm inward
- Stick adhesive sheet on the cork
- Cut paw outline (adhesive up, but not mirrored!)
- Peel & stick
Which turned out pretty good:

Dog Paw Coaster – assembled

I used Concentric infill on the top to resemble the fur pattern, but it came out way too subtle.

The owner liked it, though, which made it all worthwhile.
2026-09-17