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.
If you measure something often enough, it becomes science
On rare occasions I see a small bee or wasp investigating the bamboo tunnel nests at the windows:
Several of the tubes filled & sealed in early June have served their purpose:
Bamboo tubes have a paper-thin liner around the edge, but the mud-sealed tubes have obvious small holes chewed through the end caps:
My assumption that various insects would pick their favorite tube from the assortment seems to be working:
The medium and large tubes haven’t seen much traffic:
We’re glad to help!
An inch-long Praying Mantis stood guard on a carton delivered to the front door:
We hope to see many more of its kind.
Two views of a one-turn snail found on a lettuce leaf from the garden:
Mary has developed a Zero-Tolerance Policy for snails & slugs, so this one must start over again from the bottom of the food chain.
With sparrows excluded, the House Wrens eventually began setting up their second nest of the season, with the male proclaiming both he and his lady’s chosen nest are the best in the land:
Wrens are on our Most Favored Critter list!
Previous encounters with their ancestors and relatives:
Mary wanted less pressure in the spray while watering her plants and I suggested replacing the nozzle’s washer with a flow restrictor:
The 3D-printed TPU base is squishy enough to act as a hose washer:
A 1.5 mm thick acrylic orifice plate snapped into the opening takes advantage of the laser cutter’s precision:
For lack of anything smarter, the holes have areas that are powers-of-two smaller than the nozzle’s 14.2 mm = 158 mm² internal passage: the hole labeled 8 is 158/256 mm² = 0.62 mm² → 0.9 mm diameter.
Rather than figuring each hole’s diameter, just divide the previous diameter by √2 or rescale it by 100%/√2, which LightBurn can evaluate directly in its Numeric Edits fields. The as-cut holes are larger than their nominal size by about 0.1 mm, but any errors that might cause are definitely in the nature of fine tuning while watering the plants.
The nozzle’s Shower pattern (on the left in the picture) has a 6.8 L/minute = 110 ml/s flow through an ordinary garden hose washer. The four smallest aperture plates produced these flows:
The flow should scale with the square of the aperture diameter, which I could bully those points into suggesting, but the measurement accuracy produced by filling a gallon jug while tapping my phone’s stopwatch doesn’t justify anything fancier.
The two smallest apertures reduce the Shower pattern to a very gentle spray requiring far too long to put enough water on the plants. Mary now uses an old plastic sprinkler head with enough holes to produce a dense spray with very little force, with the flow set by fifty feet of PEX pipe running across the width of the house from the town water inlet to the hose bib.
It was a fun exercise and I learned a little more about printing TPU and fitting acrylic parts therein:
I am so glad methanol is a liquid, not a crystalline powder, because this could be totally misinterpreted:
A recent LightBurn forum discussion pointed out methanol is a good solvent for borax to produce dark-brown to black laser engravings in wood. In round numbers, 20% w/w borax will dissolve in methanol at room temperature.
I understand the toxicity warnings and don’t plan to spray it indoors. OK?
Just over a month after mounting bamboo bee tunnel nest bundles here & there around the house & yard, they have occupants!
One of the bundles of small (a few mm ID) stalks on the kitchen window:
Another bundle of small stalks on a window a dozen feet away:
A bundle of medium (five to ten mm ID) stalks lashed to a downspout:
Unlike the mud dauber wasps decorating our previous house, these little bees dart in and out without announcing their presence: we’ve never seen them at work.
Assuming a single bee works on each bundle, she apparently starts with the lowest stalk and moves upward after filling & capping it.
Larger bees have yet to discover the bundles of larger stalks out on the trees, but … so far, so good!
The first layer of a short TPU chain (about which, more later) came out vanishingly thin in the middle and much too thick on the ends:
So: let the platform cool, scrape off the wreckage, set the nozzle for Z=2.0 mm, and measure the actual gap at various spots across the platform.
Those results are the top set of measurements:
The bottom set of measurements came from a similar test a few days later, after pulling the BuildTak plate off, doing nothing other than scrutinizing it, reinstalling it, and successfully printing several TPU chains of varying design, none of which had any first-layer problems. The platform is slightly too high along the +Y and -Y edges (rear and front), with no bow worth mentioning.
My measurements are, perforce, done with a cold platform, for obvious reasons, and the TPU prints at 50 °C. I have the uneasy feeling the heater / BuildTak magnetic base can bow upward in the middle while it heats, then flatten out after a while at a stable temperature. The good news: it’s not permanently bent.
More study is needed, including thinwall boxes after letting the platform soak at 50 °C for varying times.
A friend gave Mary a small-bird birdhouse, which immediately attracted the attention of a pair of House Wrens:
The vertical black bar is a DIY Birdsaver cord.
The entrance hole was 1-½ inch ⌀, a bit larger than the 1 inch ⌀ preferred by wrens and entirely suitable for the pair of House Sparrrows who also took an interest in the property:
This led to considerable discussion and displays of outright hostility:
Sparrows and wrens disagree on nestbuilding materials, with the wrens hauling twigs into the box and sparrows hauling them back out again.
Because wrens have better PR agents than sparrows, I intervened by taking the box apart:
Although I realize that’s a lot of work for a small bird, I dumped the contents off the patio and set about reducing the entrance hole:
Because birds aren’t too fussy about looks, I sawed off half an inch of 1 inch (ID) CPVC pipe and glued it in the hole:
The outside looks marginally better:
The sparrows continued to approach the hole at full throttle, deploying landing gear and speed brakes at the last possible moment:
But they no longer fit through the hole and eventually gave up trying. The wrens resumed hauling twigs, although we’re not certain they’ll finish the project, as birds tend to build several partial nests before selecting the final one.
We hope this will end on a happier note than last year’s Wreath Robins.
