Category: Home Ec

Things around the home & hearth

Monthly Science: Bottled Water Evaporation

These emerged from a hidden corner of a basement shelf, where they’ve been sitting undisturbed for far too long:

Bottled Water Evaporation

I’ve known for a while that the PETE plastic used for nearly all bottles isn’t completely waterproof, but never had occasion to measure the results.

The laser-etched date code on the bottles says they “expired” in late August 2012, so, assuming one year of shelf life, they’ve been quietly evaporating for five years.

Sampling a few bottles shows a nearly uniform weight of 459 g. A drained bottles weighs 13 g, so let’s say the bottles now contain 445 g of water. They should start out with 500 g, although I’d be mildly surprised if it wasn’t a bit over that to prevent some dork from complaining about getting only 498 g.

Rounding in all the right directions, losing 60 g during five years works out to a tidy 1 g/month in a basement room at 60% RH.

The surface area of those wonderfully convoluted bottles might be 300 cm², so they lose 3 mg/cm²·month.

They’re near enough to 0.10 mm thick, which I’m sure is a compromise between reducing weight (and, thus, plastic cost) and incurring messy failures during normal handling. The evaporation rate surely varies as an inverse exponential of thickness, but I’m not going there.

I’m certain water bottlers know those numbers to several decimal places and can plot them versus all the interesting variables.

Memo to Self: don’t lose track of the water bottles!

2016-12-01
Amazon Packaging: Lack Thereof, Redux

Fortunately, it’s hard to damage an aluminum-body “tactical” flashlight:

J5-V2 Flashlight – Amazon packaging

A keyboard and cylindrical cell charger arrived intact, with absolutely no credit due to Amazon’s careful packaging:

Keyboard and charger – Amazon packaging

Sometimes, a box does arrive with a token scrap of padding dropped inside, but, as nearly as I can tell, it’s cheaper for Amazon to replace the occasional damaged item than to waste time and material stuffing the boxes with air pillows, eco-foam peanuts, or, heaven forfend, space-filling foam.

2016-11-30

Kenmore Progressive Vacuum Tool Adapters: Second Failure

Pretty much as expected, the dust brush nozzle failed again, adjacent to the epoxy repair:

Dust brush adapter - second break — Dust brush adapter – second break

A bit of rummaging turned up some ¾ inch Schedule 40 PVC pipe which, despite the fact that no plumbing measurement corresponds to any physical attribute, had about the right OD to fit inside the adapter’s ID:

Dust brush - PVC reinforcement — Dust brush – PVC reinforcement

The enlarged bore leaves just barely enough space for a few threads around the circumference. Fortunately, the pipe OD is a controlled dimension, because it must fit inside all the molded PVC elbows / tees / caps / whatever.

The pipe ID isn’t a controlled dimension and, given that the walls seemed far too thick for this purpose, I deployed the boring bar:

Dust brush adapter - reinforced tube - boring — Dust brush adapter – reinforced tube – boring

That’s probably too much sticking out of the chuck, but sissy cuts saved the day. The carriage stop keeps the boring bar 1 mm away from the whirling chuck.

Bandsaw it to length and face the ends:

Dust brush adapter - reinforcement — Dust brush adapter – reinforcement

The PVC tube extends from about halfway along the steep taper from the handle fitting out to the end, with the section closest to the handle making the most difference.

Ram it flush with the end:

Dust brush adapter - reinforced tube - detail — Dust brush adapter – reinforced tube – detail

I thought about gluing it in place, but it’s a sufficiently snug press fit that I’m sure it won’t go anywhere.

Natural PETG probably isn’t the right color:

Dust brush adapter - reinforced tube - installed — Dust brush adapter – reinforced tube – installed

Now, let’s see how long that repair lasts …

The OpenSCAD source code as a GitHub Gist:

	//——————-
	// eBay horsehair dusting brush
	// Hacked for 3/4" Schedule 40 PVC stiffening tube

	module DustBrush() {

	union() {
	translate([0,0,40.0])
	rotate([180,0,0])
	difference() {
	union() {
	cylinder(d1=EndStop[OD1],d2=31.8,h=10.0);
	translate([0,0,10.0 – Protrusion])
	cylinder(d1=32.0,d2=30.0,h=30.0 + Protrusion);
	}
	translate([0,0,-Protrusion])
	cylinder(d1=26.0,d2=24.0,h=100);
	translate([0,0,-Protrusion]) // 3/4 inch Sch 40 PVC
	PolyCyl(27.0,100);
	}
	translate([0,0,40.0 – Protrusion])
	MaleFitting();
	}
	}

view raw Kenmore Wand Bushings – Reinforced Dust Brush Adapter.scad hosted with ❤ by GitHub

2016-11-29

J5-V2 700 lm Flashlight: QC FAIL

So I picked up a J5-V2 Tactical Flashlight as a possible bike headlight, on the basis of a 750 (“max output”) lumen LED, zoomable beam, and use of standard 18650 lithium cells (rather than USB charging). The geometry required to stick it on the Tour Easy remains a puzzle, but an az-el dingus replacing an upper fairing mount may work well enough.

Anyhow, it seems the LED in this flashlight fell on the floor during assembly, where the (silicone?) LED emitter lens picked up a remarkable amount of dirt:

J5-V2 Flashlight – LED crud

The inside of the front focusing lens carries an array of scratches or, perhaps, a greasy fingerprint that serves the same purpose:

J5-V2 Flashlight – internal lens scratches

All vendors tell you to contact them before posting a critical review, although they often don’t provide much in the way of contact information. I sent a note with photos to J5 through their website’s contact info; having not heard anything after three days, I’ll fire up the Amazon return process …

2016-11-28
Cast Iron Pan Seasoning After Two Weeks of Use

After two weeks of more-or-less daily use, without any further seasoning:

Wagner skillet – two weeks of use

The seasoning in between the scuffs & scrapes remains in fine shape. Running the Scotchbrite pad around the perimeter obviously wears the coating, but, on the whole, nothing sticks anywhere.

I’ve started re-seasoning it after each use, which isn’t a big deal, and we’ll see how the scratches level out.

The lovely gray-black patina on the nubbly outside surface from the original moderate-woo oven seasoning requires no further attention.

2016-11-27
Kitchen Spatula Search: Solved!

A Flint Arrow stainless steel spatula works exactly the way a spatula should:

Flint Arrowhead Stainless Spatula – in action

That is, of course, a used spatula from eBay. It cost slightly more than the various new spatulas we’ve tried, but not by very much, and should last (at least from our perspective) forever.

Thanks to all of you for aiming us in the right direction!

2016-11-26
Gilmour Garden Hose Y Valve: FAIL

Mary couldn’t unscrew either of the two outlet hoses emerging from one of the (many) Y valves in her Vassar Farms plot. After deploying the Lesser Vise-Grip from my bike toolkit to no avail, I brought a Greater Vise-Grip from the shop and applied brute force. During that process, the plastic inlet hose fitting ripped off the valve and sprayed all but one of its latching teeth across the plot:

Gilmour hose Y valve – inlet fitting

As it turns out, the male outlet hose fittings on all the metal-body Gilmour Y valves in the plot have corroded:

Gilmour hose Y valve – thread corrosion

The scarred knurls show the force required to break the brass hose ring loose and unscrew it:

Gilmour hose Y valve – hose interior

Some of that crud may be hard water deposits, but the destruction of the male threads seems like a galvanic reaction among all the various metals in play.

The male fitting began rotating in the valve body, so I crushed it in the bench vise to make more headway. While I had the victim clamped down, I hacksawed a slit through the housing, pried back the edges, and freed the parts for one leg of the Y:

Gilmour hose Y valve – parts

You’d think “not corroding” would be high on the list of attributes for a garden hose valve…

2016-11-25