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

Punched Card Production
For reasons I cannot divulge at the moment, I have undertaken a project requiring Old School punched cards, although they will never be fed through a card reader. Because we live in the future, punched cards are no longer a cheap and readily available resource; I will always deeply regret trashing an entire box back in the day.

However, living in the future does confer some advantages:

Punched cards – Apollo 11 CM

The process involves a vast number of moving parts, not all of which I fully understand, but I can (generally) produce consistent results and that must suffice. This post is an overview; I will go into the moving parts in more detail so I can remember why I did what I did.

A Python program converts a line of text into an SVG file that contains either the card’s printable contents or the paths required to cut its holes & perimeter. A handful of command-line switches determines the outcome, so you run the program twice with different switches for each line of text to get a matched pair of SVG files.

A Bash script read a text file and hands each line to the Python program, producing two SVG files for each card. It then invokes Inkscape to convert the printable SVG into a PNG image, uses Imagemagic to composite the logo behind the card contents & scale the result to make my printer’s output match the laser’s dead-on positioning, then properly position the card image in a Letter-size PNG image that’s apparently the only way to print it accurately on a punched card:

Composited Letter layout – exvb-00000710-lt

That’s not full size.

N.B.: there’s no such thing as a blank card that will be punched later, because the printed card includes the text across the top. The program also suppresses the row digits where a punch will appear, thus making slight misalignments less painful and mismatched SVG files more obvious.

Print all the card images on precut 1/3 Letter size sheets of heavy cardstock:

Ext Verb cards – 0280 skewed print

Yes, the printing on the middle card is slightly skewed with respect to the precut card blank. The overall process must handle about two millimeters of positioning inaccuracy and whatever angular skew comes from the printer’s paper feed rollers / guides.

A ~~DOS~~ Windows BAT file feeds the SVG files with the holes & outline paths to LightBurn, one by one. No lie.

Put each printed card in a fixture and align its targets, whereupon LightBurn evaporates the holes and cuts the outline:

Punched cards – laser fixture overview

In my somewhat biased opinion, the results look good:

Ext Verb cards – 0270-0290 punched

The Python program also produces cards with test patterns useful for wringing out the process:

Punched cards – character tests

“Punching” a lace card is no problem and, given an all-blank text line, the result looks like a blank card:

Punched cards – lace and blank tests

If you happen to have a card punch, be my guest.

The source text for the cards comes from the Apollo Guidance Computer in the Apollo 11 Command Module, via an amazing GitHub repository. You can run a virtual AGC in the privacy & comfort of your own home.

Useful links:
- The KEYPUNCH029 dot font: thank you scruss!
- Punched card codes, of which I used EBCDIC, from a heroic collection of punched card information
- Baffling Inkscape command line doc
- Imagemagick command line options doc
- SVG doc from Mozilla
- svg.py library for making SVG files
- Python library doc
- Another punched card generator
2026-02-02
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

The poor thing went all potato chip:

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
Smashed Glass Coaster: Rivers of Crack

Looking at that big smashed-glass coaster from a different angle showed interesting patterns:

Printed Fragment Coaster – 165mm – long cracks

Although the larger fragments were still holding together when I laid them in their recesses, they apparently consist of several sub-fragments with larger continuous cracks letting the epoxy flow / ooze inside.

Now that I know what to look for, the original picture also shows them, albeit less distinctly:

Printed Fragment Coaster 165mm – overview

They’re not obvious in the scanned image of the fragments, although I could convince myself I see some:

Fragments 165mm square – scan sample

The many smaller fragments I’ve been turning into coasters probably separated from similar large chunks along such cracks, which is why I’ve never seen rivers of crack before.

Apologies if you arrived here expecting a tirade concerning the drug trade … :grin:

2025-12-08
Monster Restocking

This being the season of monsters, I rebuilt and deployed a few from last year:

Alligator – installed

Real spiders have better camouflage, but cardboard works pretty well:

Spider 1 – camouflaged

I must move them to the driveway on Friday:

Spider 2 – camouflaged

This one stands out in any situation:

Green spider

Tiny T-Rexes are just cute:

Tiny T-Rex with pillar lamp

They need support, because their heavy head bends the spine just above the hips, so they’re snuggled up against pillar lamps or each other:

Mantis and Tiny T-Rexes

The cardboard Mantis turned out entirely too fragile:

Mantis – dismantled

Reassembling the poor thing with a blob of hot-melt glue on each joint held it together.

If I used something other than corrugated cardboard, they’d likely survive longer out there.

A handful of RGBW tea lights provide just enough illumination to make them visible.

2025-10-30
Mantis Durability

A Praying Mantis appeared on the house wall:

Mantis – alert

The next morning found it huddled against the cold:

Mantis – chilled

It had reached operating temperature and gone about its business a few hours later.

I deployed a cardboard Mantis in its honor as a seasonally appropriate yard decoration, but mine didn’t survive the night nearly as well as the real one:

Mantis – dismantled

I doubt a predator was involved …

A site search will reveal previous encounters with their kind.

2025-10-29
3D Printed Smashed Glass Coasters: Being Epoxy-Tight

Each of the glass fragments in a 3D printed coaster sits atop a metallized paper reflector in its own recess and gets covered with epoxy:

Printed Coasters – epoxy fill

That’s an early printed coaster with the epoxy pool covering the entire surface. Putting a rim around each fragment to form separate pools works better.

Assuming I do a tidy job of filling the recesses, this process worked exactly as you’d expect until I printed a coaster with blue PETG-CF filament:

Printed Coaster – Set C – oblique

Other than a slightly ragged cork layer motivating me to make the cork slightly smaller and use a fixture to align it properly, the coaster looks reasonably good. However, a close inspection shows all the epoxy pools are slightly recessed below their rims.

It turns out printing PETG-CF with an extrusion multiplier of 0.8, which I figured based on fitting threaded parts together, doesn’t fuse the threads into an epoxy-tight surface:

Printed Coasters – PETG-CF leakage – footprint

Fortunately, I’d been working on a silicone mat that could take a joke. I managed to move the coaster to a plastic sheet and refill the drained pools, although they continued to drain while curing.

After the epoxy cured to a rubbery texture, I scraped off the meniscus around the perimeter of the coaster, but the bottom shows it cured in a pool of its own making:

Printed Coasters – PETG-CF leakage

The cork conceals the evidence and the result looks good enough for my simple needs:

Smashed Glass 3D Printed Coaster – Set C – in use

Memo to self: Use the correct filament preset for the job!

2025-10-22
3D Printed Smashed Glass Coasters: Cork Alignment Fixture

The printed coaster frame sits on a cork base:

Printed Coaster – inset cork

A sheet of craft adhesive holds them together; stick a generous rectangle of adhesive on the cork, then cut them at the same time. However, given the irregular perimeter, it’s basically impossible (for me, anyway) to align the cork + adhesive with the printed frame.

A single-use fixture made from corrugated cardboard make that task trivially easy:

Printed Coaster – cork alignment fixture – detail

The LightBurn layout shows the cork layer and the two fixture pieces:

The cork shape is offset 0.5 mm inward from the Perimeter shape, but I found offsetting the cardboard cut by only 0.3 mm inward produced a snug fit around the cork. The other piece of cardboard gets cut with the exact Perimeter shape and no offset, with the laser kerf providing just enough clearance for a very snug fit on the printed shape.

Align the two pieces of cardboard by eye to match their inner shapes as shown in the picture, tape them together, and the fixture is ready. In principle, the outer edges should exactly coincide: Trust, but verify.

Peel off the craft adhesive paper and put the cork in the bottom of the fixture. The cork comes off a roll and really wants to roll up again, making the masking tape holding it flat mandatory:

Printed Coasters – cork alignment template

Yes, that’s a different coaster.

Flip the fixture over, drop the coaster in place, press firmly together, peel the tape, and pull out the finished coaster:

Printed Coasters – white PETG finished

The fixture goes in the recycling bin, as those fragments will never pass this way again.

2025-10-21