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.

Tag: Art-ish

They might be Art

Biohazard Earrings

More desk clearing revealed a sketch for another trinket:

Biohazard symbol

That’s built directly from the original specs to get the spacing and symmetries correct. The freebies I could find all suffered from various degrees of bad design & layout.

A chipboard coaster provided some reassurance:

Biohazard coaster

Shrunken down to 25 mm OD, the tips become vanishingly small:

Biohazard earring – vinyl sample

It’s the same laser-safe polyurethane vinyl as the SD card reader, this time applied to 3 mm black acrylic. The “gold” ring is just parked in place, as this one wasn’t presentation-quality.

Contrary to the usual transfer-tape method of applying PSA vinyl, I stuck the sheet to the acrylic before cutting, then weeded it directly off the acrylic:

Biohazard earring – vinyl weeding

Kiss-cutting the vinyl with dot mode ate into the acrylic, but the soon-to-be-weeded areas protected the surroundings and the result came out looking pretty good. To me, anyhow.

Flushed with success, I tried some almost certainly not laser safe glow-in-the-dark tape:

Biohazard earring – GITD weeding fail

The mess in the upper left is the tape’s double-sided adhesive intended to hold the glowy layer in place forever. Of course it weeded poorly!

Seen in its natural environment, however, weeding may not be necessary:

Biohazard earring – GITD tape glow

Engraving the rebated rim leaves quite a bit of debris & scorch marks around the perimeter. A mask layer atop the GITD tape seems like a Good Idea™.

The LightBurn SVG layout as a GitHub Gist:

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2023-05-29
Plant Markers: Craft Stick Edition

Inspired by a LightBurn forum post I ~~can no longer find~~ once again tracked down, I tried my hand at ~~popsicle~~ craft stick plant markers:

Plant Markers – craft stick tests

You’d have only one name on the end of each stick, with the uncut section jammed into the ground: these are test pieces to demonstrate capability.

Wood is better than acrylic because it checks all the eco-friendly attribute boxes. Admittedly, craft sticks don’t exactly grow on trees, but we seem to ignore such externalities in nominally eco-friendly products.

Bonus: a recurring revenue stream from the replacement market!

The design, such as it is, involves subtracting the letters from a rectangle maybe half a millimeter short of their top & bottom extents and a few millimeters longer than their length. Using a chonky font with generous letter spacing may prevent prompt disintegration by weathering:

Plant Marker – craft sticks – LB layout

Engraving the letters marks their uncut sections outside the rectangle, although we know laser char on wood-ish materials fades in sunlight. The two big sticks have Radish engraved with varying density; the darker version looks better against a lighter background never found in an actual garden.

Mary thinks they might be a nice fundraiser for the next Master Gardener Plant Sale.

Outdoor field tests seem appropriate …

2023-04-21
World War II Dog Tag Layout

Quite some time ago, I hammered out G-Code to engrave ersatz dog tags for a Cabin Fever demo:

Cabin Fever Dog Tag

A dozen years later, making a World War II dog tag is a whole lot easier:

John Q Public – WWII dog tag

Well, “easier” if you allow laser engraving in white-on-black Trolase using a font intended to mimic a typewriter.

Close enough, methinks.

Which comes from a simple layout:

John Q Public – WWII dog tag – LB layout

The outline traces a scanned image of my father’s tag, fitting a few hand-laid splines around the curves:

John Q Public – WWII dog tag – spline curves

I generated a random serial number based on my father’s draftee status (he was in his early 30s during his South Sea Island tour) and state of residence; my apologies to anyone carrying it for real. His blood type was A and (I think) the religion code marks him as “Brethren”, a common group in my ancestry.

Given the outline, various plastics, and a laser, other effects become possible:

WWII dog tag outline test

It might come in handy for something, someday.

The LightBurn SVG layout as GitHub Gist:

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2023-02-20
Laser Engraved Fabric

This is more along the lines of searing the fuzz, rather than actual engraving:

Laser Engraved Fabric – cotton knit

The top row is 15% power at 400 mm/s, the bottom is 25% power, and the fabric was a cotton t-shirt from the Box o’ Shop Wipes.

Applying the higher power to the inside of sweatpants fabric, whatever that might be:

Laser Engraved Fabric – sweatpants

Both of those were easier to see in the slanting sunlight of a later winter afternoon.

The best results come from the lowest feasible power applied at the fastest practical speed, with obvious size and complexity limitations.

I think this will most useful on a removable tag labeling a piece (perhaps cut from a larger pattern), rather than branding the piece itself.

2023-02-13
Laser-Engraved Bentley Snowflakes

Algorithmic snowflakes make for interesting coasters and decorations:

Snowflake Hangers – frosted

But they lack the complexity of real snowflakes:

Wilson Bentley Photomicrograph of Dendrite Star Snowflake No. 842 – SIA-SIA2013-09114 – rescaled

That’s from the Smithsonian collection of the Wilson Bentley snowflake photos from back in the 1890s, all of which are CC0 = Public Domain images.

So pick a nice image, say #842, clean it up a bit, and isolate the flake from the background:

Snowflake No. 842 – SIA-SIA2013-09114 – isolated

Pick a threshold level to prettify the result:

Snowflake No. 842 – SIA-SIA2013-09114 – Threshold

Then engrave it into the back of an acrylic mirror scrap, so the darkest parts become most transparent:

Bentley 842 – engraved mirror – white background

Which looks better when seen against an illuminated background:

Bentley 842 – engraved mirror – color background A

Well, I think it does:

Bentley 842 – engraved mirror – color background B

Maybe four different snowflakes atop those squares?

Gotta get this ready for the next snow season …

2023-02-08
Holly Coaster: Improved Mirror Setup

Other than demonstrating that it’s possible to laser-engrave a 3 mm deep pocket in a ¼ inch thick piece of scrap paneling, the process didn’t have much to recommend it:

Holly Coaster – mirror flaws

So I re-did the layout to put the 3 mm mirror in 3 mm thick plywood:

Holly Coaster – overview

The coaster has a self-adhesive cork pad on the bottom, which required an intermediate adhesive layer holding the aluminized Mylar reflector on the bottom of the mirror to brighten the colored areas.

The LightBurn layout shows all the pieces:

Holly Mirror Coaster – LB layout

The plywood cuts with the good side down, although “good” is certainly a judgement call with B/BB grade plywood. I cover the good side with blue painter’s tape to reduce scorch marks. In a real application, you’d do some sanding and finishing, probably before cutting; in this case, I want to see what happens to bare wood in coaster duty.

Engrave and cut the mirror with the backing upward:

Holly Coaster – removing mirror layer

The tracer rounds may be burning aluminum.

I colored the engraved areas with fat-tip permanent markers, despite knowing the alcohol will crack the acrylic. In real life, you’d use spray paint, probably with laser-cut tape masks.

The adhesive layer extends 2 mm beyond the mirror perimeter to stick onto the bottom face of the plywood:

Holly Coaster – adhesive placement

Peeling off the paper reveals the adhesive tape stuck to the back side of the mirror:

Holly Coaster – adhesive exposed

Apply the similarly embiggened aluminized Mylar to the adhesive:

Holly Coaster – mylar placed

Cutting the holly shape directly from the original foot-square adhesive sheet lets me tuck smaller shapes into the remaining uncut areas. In a production environment, however, joining the Mylar and adhesive (perhaps using pre-cut squares), then cutting them as one sheet would definitely simplify the process.

Then peel-n-stick a cork disk (thus explaining why the plywood is exactly 4 inch OD) on the bottom:

Holly Coaster – edge view

I’ve been aligning the cork by feel, which explains the half-millimeter overhang along the right side. Inexplicably, I have yet to justify an alignment fixture.

The LightBurn SVG layout as a GitHub Gist:

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2023-01-09
Frosted Snowflakes

After the first two snowflake coasters, it finally penetrated my thick skill that putting a 1 mm hole in the flake cut from the center of the plywood would convert it into a decorative window hanging:

Snowflake Hanger – plywood

Admittedly, I may be using the word “decorative” in a manner you had not previously encountered, but work with me on this.

Cutting a similar flake from transparent acrylic looks better:

Snowflake Hanger – blue acrylic

Transparent acrylic turned out to be, well, too transparent, so I set up a LightBurn layout to “engrave” a light frosting on the flake before cutting it out:

Snowflake Hangers – engraving in situ

That worked for all subsequent flakes, but I had to do something about the first few flakes. After realizing that the time to engrave an object depends only on its width, I set up a rectangle with the proper parameters, snugged two forlorn flakes next to each other, and fired the laser:

Snowflake Hangers – retroactive engraving

I thought using cardboard was a Good Idea™ for a stable backing, but lightly vaporizing the top layer produced an unbelievable amount of filth:

Snowflake Hangers – frosted

I had to scrub those poor flakes with dish detergent and a toothbrush to get them even close to their former pristine state; the blue one may never recover.

Anyhow, frosted flakes look good if you don’t look closely:

Snowflake Hangers – frosted

The grid pattern comes from the window screen in direct sunlight; the vertical bars are DIY BirdSavers.

The LightBurn layout produces 120 mm coasters to fit my 20 ounce mugs:

Snowflake Coaster 120 mm – LB Layout

You get two hanging flakes: one plain plywood and one frosted acrylic!

The LightBurn SVG layout as a GitHub Gist:

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2023-01-06