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.
Who’d’a thunk it?
Even though cicadas are completely harmless, Mary was quite startled to discover one crawling up the back of her garden pants:
It seems the cicada mistook her for a tree.
They’re handsome creatures:
They’re very conspicuous on fabric:
I teleported it to a maple tree, where it was better camouflaged:
When last seen, it was headed upward at a pretty good pace. We wished it well on its adventures …
Mary found this gadget gnawing holes in a bean:
The lump on the right is frass, not a mini-me tagging along behind.
We had no clue what it might be when it grew up, but Google Lens suggested a Striped Hairstreak Butterfly caterpillar and, later that day (and for the first time ever!), we saw an adult Hairstreak fluttering on a goldenrod in the corner of the garden.
As with all caterpillars, you’d never imagine the adult butterfly. It seems they move their hind wings to make predators aim at the south end of a northbound butterfly …
The toad population has apparently been spending more time near the Mighty Wappinger Creek, rather than around the house, during this very dry summer, so this small toad at the garage door came as a surprise:
A few days later, Mary spotted a larger toad tucked into the spice garden:
Small tree frogs sound off in the darkness around the house, but we’ve never seen any of them.
We wish them great success in their future bug hunts!
For whatever reason, a two-outlet junction box stands outside the Credit Union:
The slanted conduit certainly looks in need of an elbow to line it up, doesn’t it?
It seems whoever installed it, many years ago, simply forced the conduit to line up, no matter the consequences:
The threaded entries on the die-cast outlet box were never intended to cope with that much misalignment; half the bottom has vanished. I think the round box on the top originally held a floodlight to wash the (uninspired) building facade at night, but those days are long gone.
If the conduit has horizontal underground runs, both are certainly full of water by now. The white(-ish) “Romex” cable insulation looks like ordinary indoor wiring, not the grayish direct-burial sheath, but it may be sun-bleached after years of exposure.
Surely there’s a tripped GFI on that circuit …
We exchanged waves as he rode by Vassar Farms:
Although I can rarely hang with real roadies, I can put the fear in ’em for a while, so the chase is on.
About 25 seconds later, I’m southbound on Rt 376, accelerating past 20 mph = 30 feet/s. The overtaking pickup, which I haven’t noticed yet, is signaling a right turn at Zach’s Way, 350 feet ahead:
The pickup enters my field of view, but I can’t see the turn signals:
Two seconds later, the driver is braking:
During the next three seconds, the driver realizes I’m going much much faster than your usual cyclist and is braking hard:
My startled shout (“Don’t even think about it!“) may be misinterpreted, but I try to be friendly,
Alas, the cyclist turned into Boardman Road and all that adrenaline went to waste.
Elapsed time since the fender appeared: six seconds.
Being the type of guy who uses metal bits & pieces, I thought this might be a useful aluminum rod:
It turns out to be an aluminum tube holding a lithium cell and a reservoir of oily brown juice:
The black plastic cap read “EonSmoke”, which led to a defunct website at the obvious URL. Apparently, EonSmoke went toes-up earlier this year after ten years of poisoning their customers, most likely due to “competitor litigation”.
The black cap held what looks like a pressure switch:
Suck on the icky end of the tube to activate the switch, pull air past the battery (?), pick up some toxic vapor around the heater, and carry it into your lungs:
Maybe there’s a missing mouthpiece letting you suck on the icky end, activate the switch, pull vapor through the heater, and plate your lungs with toxic compounds. I admit certain aspects of my education have been sadly neglected.
The lithium cell was down to 1.0 V, with no overdischarge protection and no provision for charging, so it’s a single-use item. I’m sure the instructions tell you to recycle the lithium cell according to local and state regulations, not toss it out the window of your car.
I had to wash my hands so hard …
The test pieces for the Mesh Screen Frame came out a bit short:
Which turned out to be the M2’s first extruder clog in a long, long time. The printer shut down normally, with no error messages, and the objects look fine as far as they go, making the diagnosis fairly simple.
Just to be sure, I verified:
It’s worth noting I use only PETG plastic from a single supplier, so Slic3r uses set-and-forget temperature and speed values, and I manually change colors only on those rare occasions when color matters. Most clogs occur after switching from a higher- to a lower-temperature plastic (PETG to PLA), where a chunk of soft-but-not-molten plastic jams in the nozzle; not the situation here.
Unscrew the clamp screw enough to release the spring pressure on the idler bearing:
Undo the various screws holding the block to the drive gear housing and pull it off. The drive block looked fine, with a clear round hole along the entire filament path, so that’s not the problem.
The filament snippet sticking up out of the hot end also looked fine, apart from the expected drive gear gouge, with nice serrations below that point into the hot end. It’s the third filament from the top in this group photo:
Although it’s called a “cold pull“, you can’t yank a solid hunk of plastic out of the hot end. Warming the PETG to around 200 °C and pulling the snippet out produced the long tapered end shown above.
I rammed another snippet into the hot end to bond with whatever was inside:
Which produced the top snippet above, with no particular trouble found.
Repeating the process with some nylon (?) cleaning filament:
In need of more traction, I sank a #60 twist drill into the molten plastic:
Let things cool a bit, haul it out (it’s halfway in the picture above), and we’re making progress:
I warmed the PETG-encrusted bit over a butane flame, wiped it on a shop rag to get most of the plastic off, then drilled a few holes in a hardwood block.
Note that a #60 drill (40 mil = 1 mm) is much much much larger than the nozzle hole:
The vertiginous view looks downward into a small hand-held mirror.
Although some folks swear by 0.3 mm carbide drills for nozzle cleaning, I doubt I could avoid wrecking that nice round 0.35 mm hole. The new red silicone coat has chipped from around the nozzle over the last few sessions, so it’s no longer wiping the top layer.
During all this flailing, something that might have been a glass fiber emerged from the nozzle while shoving one of those PETG snippets into the hot end. Of course, when I pried it out of the goo with tweezers, it snapped away into the clutter, never to be seen again. Despite being covered in PETG, it was a rigid sliver, rather than the gooey extruded thread. Perhaps the whisker extending from the PETG surrounding the drill bit was a similar fiber, but I didn’t notice it at the time.
One of the PETG cold warm pulls contained two brownish lumps:
This chunk doesn’t appear in the group portrait. It’s obviously been melted, measures a bit under 1.75 mm diameter, and the drive gear tooth marks show it passed through the filament drive block under motor control, most likely retraction.
Passing the Xacto Knife of Inquiry through the leftmost lump split it neatly in two. The left section:
And the right section:
In person, the sections look like granular / burned residue surrounded by clear PETG. I’d expect anything burned to come from inside the hot end, but I don’t know how those lumps would get surrounded by nice, clear PETG inside a reasonably cylindrical section with drive gear notches.
Anyhow, the clog has now Gone Away™ and the M2 extrudes just fine. I’ll declare victory and move on …
The Smell of Molten Projects in the Morning 