An excuse to use that spider photo again

Here's yet another Reddit-comment transplant, this time from this thread about scary animals in the USA, in the opinion of...

Huntsman spider


I opined:

1: The house centipede. Perfectly harmless, but practically a prototypical creepy-crawly, and very common.

2: The toe biter. Apart from the egg-carrying creepiness, toe-biters have that name for a reason, and their bite may be the most painful of any insect. Won't kill you. May make you kill yourself.

(Most insect-bite-pain-scales, like the not-entirely-serious but well-researched Schmidt one, don't cover large swathes of the arthropods. The Schmidt scale, for instance, only covers the stinging Hymenoptera - wasps, bees and ants.)

I regret I have been unable to locate a YouTube, or even LiveLeak, video of someone deliberately getting bitten by a toe biter. All those marvellous videos of people eating staggeringly hot peppers (or just straight capsaicin), or volunteering to be tased, or shooting each other with fireworks, or engaging in the various other things that only other drunk 20-year-olds used to get to watch... there are even voluntary Irukandji jellyfish stings! But no toe biters.

If you can't find me video of some idiot being turned into a flowing puddle of agony by a toe biter, I of course welcome your suggestions of even more terrifying American fauna and/or flora.

Dead kids, dead animals, and other such jollity

Here's another post that was about to be a comment on a Reddit thread that no bugger'd read because the thread is five whole hours old.

The thread is about this picture of some Chinese doctors (disrespectfully translated versions here and here) bowing in respect to the body of a terribly young organ donor. She donated pretty much everything, and was only eight years old.

Needless to say, the Reddit conversation immediately wandered as far and fast from the topic as it could, thanks to someone noting the similarity between the doctors' respect for the dead girl and a hunter-gatherer's respect for the animal he's just managed to kill.

(Put like that, it sounds as if it's about half an inch away from turning into 4chan dead-baby jokes. The thread isn't actually like that. Well, no non-deleted comments with a score above minus 50 seem to be, anyway.)

This comment in particular pressed one of my personal Talk Buttons, so now that I've spent a couple of hundred words explaining the background, here's my Canned Rant on the subject of carnivores who never see an animal killed:

I don't think it's bad that people don't see where their meat comes from any more, but I think everybody who eats meat should at least visit an abattoir once. Not watch a documentary, visit one, so you get the full experience - sights, sounds and definitely smells. The smell of blood cooking on the steam pipes, the smell of various useful components of animals that people aren't going to eat, the smell of the hair being burned off the hog bellies by a guy with one of the safest, and least interesting, jobs in the whole awful place...

Talk about your "life leaving the eyes..."; how about seeing a pig screaming, thrashing around, managing to get its back feet off the hook and then flapping on the concrete floor, still fettered but no longer hung, as the blood fountains out of its throat and its dog-level brain may actually realise it's now every bit as fucked as it thought it was going to be if it got shoved up that ramp with all the rest...

(Sheep and cows don't seem to have any idea what's coming, thanks partly to clever feed-ramp design. Pigs figure that shit out, though, and do NOT want to go into the building. Perhaps that problem's been cracked now with even more animal-psychology; I saw all this, including the unexpected Porcine Murder Show, on a school trip more than 25 years ago.)

I still eat ham and bacon. But only occasionally.

(I also don't know whether it was normal, back then, for slaughterhouses here in Australia to hang up very-much-conscious pigs and cut their throats, without stunning them first. The usual reason for hanging and bleeding conscious animals is to comply with kashrut and/or halal rules, but obviously there's no such thing as kosher pork, so that couldn't have been it. If an animal's stunned or brained before being bled, then this sort of drama's only ever going to happen, with or without an audience of rather alarmed Agricultural High School kids, if the stunner-guy manages to miss.)

Like piranhas with a cow

It is possible that you do not, as a matter of course, have at least fifty cockatoos turn up in your back yard for a feed every afternoon.

If you do, I advise you to, as I do, purchase your bird seed in 25-kilo sacks, and not attempt to feed the cockatoos with a supermarket seed bell.

Those don't last.

(Available in HD!)

The loud scrapey-thud noises happen every time a 900-gram bird uses the microphone on top of the camera as a perch.

Extension of this behaviour brought the video-shooting to a halt when only about half of the seed bell was gone. But, as I said, you get the idea.

(I know it's not good to give them a small source of food so they fight over it. The regular seed I spread on the table, and on the deck itself, which greatly reduces the Skesis act.)

Occupational canine hazards

A reader writes:

I love the Australian expression "blind as a welder's dog". [Meaning blind drunk, not unable to see; example usage here. -Dan]

I don't hang out with a lot of welders, though. Do they actually tend to have blind pets? Has the RSPCA had something to say about this?


Nugget the dog
Nugget, here, is actually a plumber's dog, not a welder's. And he's not blind in either of his mismatched eyes.

Arc welding is the most common kind today (well, if you don't count the resistance welding that I think is now mainly done by robots), and also the worst for the eyes. It produces a lot of light, including very strong ultraviolet light in the dangerous UVB and UVC bands. (UVB is what gives you sunburn; UVC is even worse, but the earth's atmosphere fortunately absorbs functionally all solar UVC. Ordinary "blacklight" ultraviolet lights produce only the close-to-visible UVA light, which is almost entirely harmless.)

You don't just need eye protection when you arc-weld; you need all of your skin covered too, partly to avoid burns from flying bits of hot metal, but mainly to avoid getting severe sunburn surprisingly quickly.

Gas welding is a bit less risky for the eyes, but it's still very bright and it still makes plenty of UV. So you need eye protection for that too, unless you're welding caveman style, where you line everything up and then close your eyes and use the Force to guide you.

And yes, hard-ultraviolet light exposure can blind you. Any light - including invisible infrared - that's bright enough can damage the retina, essentially by simply heating it up (I ramble on about this at some length in this old laser review). UV light can also directly damage tissue, though, which is what causes sunburn.

Invisible light, like UV and infrared, is particularly dangerous. The brain can't tell it's there, and so won't activate the "blink reflex" or contract the pupils.

Usually, however, acute hard-UV exposure doesn't do any readily measurable permanent damage. Instead, it gives you photokeratitis, essentially sunburn of the surface of the eye. Photokeratitis, like regular sunburn, doesn't show its symptoms until some hours after the exposure, so you can give yourself a big old dose of it without noticing. And it's extremely unpleasant; it feels not unlike having sand in your eyes, but that feeling can go on for days.

On the plus side, photokeratitis makes an excellent wake-up call for people who've not been protecting their eyes from hard UV, whether it's from welding or ordinary sunlight (or sunlight plus reflected sunlight from snow; acute "snowblindness" is photokeratitis). Better a day or three of misery than no warning at all until you suddenly notice you can't read any more.

It's quite easy to damage your retinas severely without even knowing you're doing it, because the brain is very good at plastering over holes in retinal response. Normal eyes come from the factory with one built in scotoma, the "physiological blind spot", but you can only detect it indirectly. Your brain will perfectly happily cover over other blind spots, too, and you won't even know until you start, say, running your car into people because you really and truly didn't see them.

So, what of welders' pets, presuming they don't just leave them tied up in the back of the ute?

Well, on balance, I think they're pretty safe. Dogs can get photokeratitis just like humans, and probably won't connect the pain with the light that caused it, or even make it obvious that they're suffering. So if a dog habitually hangs around near its owner and checks out what he or she is doing, and he or she is making dangerously bright light, it's perfectly possible for the dog to end up with severely impaired vision.

But the light from welding isn't deadly pure invisible UV or IR. It's very obviously very bright, not unlike the sun. And dogs are not known for staring at the sun until they go blind.

(Almost nobody voluntarily looks at the weld they're making without some kind of eye protection; the main problem arises when welders use eye protection that isn't good enough, attenuating visible wavelengths well enough to make the weld viewable, but letting through too much UV and IR.)

Distance can also make a big difference. The reason why the light from welding is so very dangerous to the welder is that it is, of necessity, right there at arm's length in front of you. Get even a short distance further away and the inverse-square law will help you out.

Maybe it's more of a problem than I think, though. Noticing that your dog is suffering increasing retinal damage is even harder than noticing that it's happening to you. Perhaps the typical welder's dog actually is half-blind or worse, but the only obvious evidence of this is that he now keeps losing the stick he's meant to be fetching.

Alice the dog

Alice, here, isn't any kind of tradesman's dog, but she does have lousy eyesight, even when she's not obscuring it as here depicted.

Alice the dog

Fortunately, this doesn't seem to impact her lifestyle at all.

When cat toys are outlawed, only outlaws will have cat toys

A reader writes:

I've got a couple of cats, had 'em for a couple of years. I have trouble motivating them to chase their toys, ping pong balls, etc - it works once or twice a week, but otherwise they just ignore it. So I've decided to bring out the big guns and get a laser pointer.

It seems they're much harder to get in Australia since all those airplane shenanigans, even though I hardly need a galactic-range pointer.

Was wondering if you had a suggestions for where to nab a laser pointer appropriate for kitteh?


It's still pretty easy to buy your basic button-cell keychain laser pointer from electronics stores here in Australia. I think there might have been a brief drought when the new Think Of The Children Or The Pilots Or the Puppies Or Something OMG JUST BE AFRAID EVERYONE law was passed, while the stores made sure that the humble cat toys they were selling yesterday hadn't suddenly been transmuted into illegal death rays.

But basic laser pointers are easy to find now. Here's one at Altronics, here's one at Jaycar (Jaycar have several other options, too).

[There are cheaper pointers on eBay, from sellers who at least say they're in Australia, which means they shouldn't be sending your purchase through Australian Customs to be confiscated by our ever-vigilant protectors. People may still be selling cheap pointers at the markets, too. If you believe price equals quality, on the other hand, note that the writhing transporter-accident creature that absorbed both Dick Smith Electronics and Tandy (Radio Shack) in Australia will be pleased to sell you a keychain pointer for $36.98 - at "DSE" here and at "Tandy" here!]

Altronics and Jaycar both want $AU14.95 for a bloody keychain pointer, which is of course a frankly insulting price. For little more than twice that much at current exchange rates a nice man in China will sell you a whole non-contact infrared thermometer, that incorporates an aiming laser. But which I'm sure will whistle through Australian Customs, just like all of the "laser-guided" circular saws, ultrasonic distance measurers, scissors, et cetera.

I chose not to choose a $15 keychain laser. I chose something else.

Home-made laser pointer

This prison-shiv of a laser pointer...

Home-made laser pointer

...took a lot longer to photograph than it did to make.

It's pleasingly bright at around 25mA current - much brighter than your standard button-cell cheapie, but not bright enough to pose any real eye hazard. It has an egg-like shape that feels good in the right hand, with a nice clicky steel switch-bar under the thumb. It has adjustable focus, so you can widen the light out into a splodge of quantum speckle at will. And it had a total parts cost about the same as the abovementioned stupidly-expensive keychain lasers. You could easily make something similar for less than $10, including the two AA batteries.

(It's quite hard to find laser pointers that take AA batteries, these days. Those little button-cell pointers are churned out by the zillion, and many pen-shaped pointers use a couple of AAAs - but if you want the substantially higher capacity-per-dollar of AA power, I think you may have to assemble your own pointer. Or, at least, hack bigger batteries onto a smaller pointer.)

The key component in a do-it-yourself laser pointer is a laser diode, lens and heat-sink assembly - commonly referred to as a laser "module", or "package".

Well, that's the key component unless your DIY ethic requires you to build the module from scratch, as well.

(The state of the DIY art has not, to my knowledge, yet reached actual home-made laser diodes. It's surprisingly easy to make your own very dim LED, though!)

There's no financial reason to build your own laser module, because you can buy ready-built modules in various shapes and sizes - even in colours other than red - startlingly inexpensively on eBay, or from dealers like DealExtreme. And no, Australian Customs won't confiscate your laser module, either - or, at least, they didn't confiscate any of mine.

Because, like an IR thermometer, a laser module is demonstrably not a laser pointer. And it is laser pointers that are illegal here, don't you know.

(I haven't tried importing a genuinely dangerous high-powered laser module, of the type used in hefty laser "pointers" that were already illegal in Australia before the current ridiculous laws went through. I would make a small wager that you would have no trouble importing such a module at all, though. But don't worry - as we all know, those scary domestic terrorists who we keep being warned about, but who mysteriously never seem to actually commit any acts of terrorism, must be so impotent on account of how they are too dumb to figure out how to connect a multi-watt invisible-beam IR laser module - you know, a laser that's actually dangerous - to a battery.


The question for the non-terroristic cat-toy maker is which of the (very) numerous cheap red laser modules will actually suit your purpose. I am happy to announce that I've done the legwork for you, here, for DealExtreme's range at least. I bought a few of their finest, cheapest red laser modules, and this one, yours for a princely four US dollars and six cents delivered to anywhere in the world, is the one you want.

It's got a nice big sturdy heat-sinking case, it's usefully, though not dangerously, bright from modest power, and it's got the abovementioned adjustable collimating lens, too.

The other components of a DIY laser pointer:

1: Batteries. Two AA alkalines, in this case; feel free to use some other combination if you like. (Three D cells would give you outrageously long run time.)

The batteries you choose determine which...

2: ...resistor you should use in series with the laser module.

Laser diodes, like their older relatives, the LEDs, need some kind of current limiting to prevent them from going into thermal runaway and dying very quickly. Inline resistors are usually the simplest option.

I found that the four-dollar DealExtreme module ran nicely, but not excessively, brightly from two AAs through three 91-ohm resistors in parallel, for an aggregate 30.3 ohms. I couldn't find a roughly-30-ohm resistor for the final assembly, so I used a couple of 16s in series. Small laser diodes draw only tens of milliamps, so little quarter-watt resistors are more than good enough.

If you buy some other laser module, don't just trust the "2-4.5V" or whatever that was listed on the eBay auction, hook it up to two AAs, and kill it. You'll need to put a multimeter in milliamps mode - which, remember, has a little resistance of its own - in series with the module and fiddle with batteries and, initially, larger resistance values, to find a suitable value. (That's how I ended up with three 91s in parallel - I started with one 91-ohm, which gave a very dim beam, then put another one in parallel, et cetera.)

The quick and dirty way to figure this stuff out for a laser module of unknown provenance is by starting with resistor values that're clearly much too high - by themselves, across the power supply, they'll let much less than the module's rated current flow - or by using a bench power supply that lets you limit voltage and current. Then you reduce the resistor value (or gingerly wind up the current knob) until the dot stops getting noticeably brighter. Wind it back a bit from that point and you should have a safe value. Or just stop when the dot's still getting brighter with more current, if it's already bright enough for your purpose.

Or you can, of course, sidestep all of this and just buy that DX module, and run it from two series 1.5-volt cells and about 30 ohms.

3: A battery holder. Little black plastic holders like the one I used are almost free on eBay, or you can bodge something up yourself. (Thumb-tacks make good battery contacts, by the way.)

4: A switch. I used a microswitch I had sitting around, which gives a pleasing tactile feel. Any old switch will do, though. Momentary, like my microswitch, if you want the usual hold-down-the-button kind of laser pointer, or standard "unbiased" if you want a pointer that stays on by itself.

(For about the same almost-free price as a black plastic AA-battery holders, you can get a black plastic AA-battery holder with an unbiased switch built in.)

5: Stuff to hold it all together. Solder and glue, for a more professional result; tape and positive thoughts, for a less professional one.

The weird organic-looking white stuff on my pointer is a couple of blobs of polycaprolactone plastic, about which I must digress, because it's brilliant stuff.

At room temperature, polycaprolactone is a tough white plastic, like nylon. But above about 60°C it becomes a pliable, bouncy, transparent putty-like material.

Polycaprolactone is transparent when it's hot

(This is the laser assembly before the second blob of polycaprolactone had fully cooled. It'd be fun if it stayed like that, but you can't have everything.)

You take polycaprolactone granules, and you put them in boiling water, and they turn clear and stick to each other. Just stirring the growing blob around a bit will pick up any loose pellets. Then you fish the spongy blob out and squeeze the hot water out (a slightly painful procedure), and then form the blob to suit your task, usually by just sticking it onto something and squeezing it into shape. Hot polycaprolactone sticks well to all sorts of surfaces, but not so well that you can't peel it off if you make a mistake. And you won't get scalded while doing this, because unlike water, the plastic is lousy at transferring heat to your fingers.

(If you heat polycaprolactone above 100°C, by, for instance, microwaving it instead of putting it in water, it apparently becomes a lot stickier, as well as much more able to burn you. So you might want to leave those higher temperatures to the rapid fabricators. I needed to smooth a little bit of my polycaprolactone blobs, so I wafted a small butane flame past the plastic. But then I smoothed it over with a damp screwdriver, instead of my finger.)

As polycaprolactone cools, it clouds up and stiffens, but does not appreciably shrink. If you haven't gotten your new plastic part shaped right before this happens, just pop it back in the water to re-soften. It's easier to re-shape polycaprolactone than it is to shape it in the first place, because there's less water to squeeze out. You can re-heat the plastic as many times as you like, too, and any excess can go back in the bag for later.

Polycaprolactone in the molecular weights that make it behave in this useful way is manufactured in vast quantities by at least two companies, Solvay and Dow Chemical. Which is great to know if you need a ton of the stuff, but not so much if you just want to replace a missing knob on a radio. (That was my first polycaprolactone project. It worked beautifully.)

Other companies repackage polycaprolactone in smaller quantities at large markups. "Polymorph", "ShapeLock" and "Friendly Plastic" are all polycaprolactone. The first two are very much the same; Friendly Plastic comes in a white-pellets version too, but is also available in a wide range of more-expensive coloured versions. You can colour polycaprolactone yourself, but if you need even, repeatable hues and/or metallic effects, and you don't need a huge amount of the stuff, then you'd probably do better just buying Friendly Plastic.

(The bone-white version is of course preferable, if you want to make creepy biomechanical thingummies.)

If you're in Australia and you just want to see what polycaprolactone is like, get yourself a hundred grams of "Polymorph" from Jaycar for $AU11.50. (Plus delivery, if you buy it online rather than over the counter.) That may go a surprisingly long way; I didn't weigh the Polymorph that went into my laser pointer, but judging by volume it was probably no more than 25 grams.

If you're in the States, there are lots of retail polycaprolactone sources. Try the Maker Shed.

If you're outside the States and want a larger, but not vast, amount of the stuff, many companies stand ready to rip you off.

You can place an international order at and pay for it, with a pleasingly low shipping fee - and then they'll refund your money, because they don't actually ship overseas. And then they'll tell you to order from Jameco instead. Jameco's international shipping fees aren't mentioned on their site; you can place an order and give your payment info and wait for the delightful surprise, or you can e-mail them, whereupon they will inform you that their cheapest price to send a $US24.95 half-kilo of Shapelock to Australia is $US39.

Sorry. Just had to get that out of my system.

OK, here's how people outside the States - and possibly inside, actually, depending on how all the prices shake out - can buy polycaprolactone at a non-stupid price. Go to this eBay dealer in the UK (on, on, who's currently on holiday until the 8th and has invisibilised their auctions, but will actually still let you place an order via this listing. They'll sell you 500 grams of Polymorph-branded polycaprolactone for £9.50 plus quite reasonable delivery, with a microscopic discount for multiple half-kilos.

[UPDATE: As pointed out in the comments below, that eBay dealer has a separate Web site too, from which you can download a great PDF about what you can do with Polymorph.]

To make sure I get my order in before all of y'all, I just ordered a key, man, for a total of £32.75 delivered to Australia. That's about $AU54.20, or $US49.80, as I write this.

A kilogram of polycaprolactone is quite a lot - especially when you consider the near-infinite reuseability of the stuff. Unless I suddenly start building sizeable structures, I don't anticipate having to buy any more for some years.

Jaycar offer discounts for bulk purchase, but a kilogram of Polymorph from them is still $AU89.50 ex delivery. So the eBayer in the UK looks like a good deal.

Hm. This post started out being about making a laser, and ended up about making freeform plastic bones. Eh - it'll do.

Do feel free to discuss either subject in the comments!

They come over 'ere, they take our bird-seed... wait, no they don't

Blue-eyed cockatoo

I originally thought this blue-eyed cockatoo was, in another triumph of creative bird naming, called a Blue-eyed Cockatoo, but as commenters below point out, it's actually a Little Corella.

It showed up all by itself at the feeding table, and grumpily snapped at the sulphur-crested cockatoos when they tried to get some of the seed. The newcomer is significantly smaller than a sulphur-crested, with a much less impressive crest, but it's bigger - and apparently more bad-tempered - than a galah.

The newcomer was very successful at keeping the usually-boisterous mob of bigger birds away for a few minutes, while it filled up on the mound of sunflower seeds. (I am, as regular readers know, engaged in an ongoing experiment to determine whether wild cockatoos can become obese.) Then it flew away.

It took me a few tries to identify this bird [and then, as I've mentioned, I got it wrong...], because I couldn't find anything resembling it in Birds in Backyards' excellent Bird Finder. The Finder usually leads you quite easily to the right Australian bird - it's my first stop whenever I see a new feathered beastie here in Katoomba. But it didn't work this time.

I thought that meant this wasn't an Australian bird; if it actually had been a Blue-eyed Cockatoo, it would have been a slightly endangered native of the Bismarck Archipelago of New Guinea. That's about 3100 kilometres (1926 miles, 558 leagues, 15,410 furlongs) from this house. As the crow, or cockatoo, flies.

So I figured this one was probably an escaped pet. But since it's actually a Little Corella - the bags under the eyes are quite distinctive, if the crest isn't up - the only odd thing is that I've never seen one at the feeder before. I don't know why I didn't find this bird's page on Birds In Backyards. Perhaps someone forgot to tick the "blue" box in the "colours" part of that database entry, or perhaps I insisted it was finch-shaped, or something.

Our fifty outdoor pets

If you like watching large decorative birds eating seed, flapping around and squabbling with each other, this is the blog post for you.

As regular readers know, I shovel ever-increasing quantities of seed down the throats of whatever birds deign to visit the table on our deck. Most of the freeloaders that show up are Sulphur-crested Cockatoos (they even outnumber the pigeons!), and I've shot video of them before. But it only now occured to me that I could clamp the camera onto the table and go away.

So that's what I did.

This is before the full afternoon mob showed up, so it's relatively civilised.

Same table, most of the same cockatoos, a little further away.

And now, the afternoon rush!

It gets a bit samey toward the end, there, but I laughed every time another huge beak filled the screen, so I let it roll.

(I swear one of 'em tries to say "cock a doodle doo" at 5:44.)

God's a bastard, instalment 34827

I just put out some more bird seed, because I noticed that this morning's supply had been depleted by the usual mob of colourful creatures, but also because one of the birds still picking at the few seeds left clearly needs all the help it can get.

It's a cockatoo with a fairly advanced case of "psittacine beak and feather disease". I could have taken a picture of it, but it always makes me so sad to even look at a cockatoo with this disease that I just couldn't stand it.

It also makes me sort of aimlessly angry, wishing God existed so I could ask Him what the bloody hell He thought He was playing at.

Psittacine beak and feather disease is, in brief, a virus which takes one of the most beautiful creatures in the world, and makes it uglier and uglier until it is so ugly that it can no longer eat, whereupon it dies. If opportunistic infections of the bird's devastated feathers and tumorous, necrotic beak and claws haven't killed it already, that is.

There is no cure, or even specific treatment, for psittacine beak and feather disease.

There are hundreds of diseases of humans and animals that're just as horrible. But few are as purely and plainly awful as this one. It's like a metaphor for the unfairness of life.

Right - I'm off to Cute Overload for a while.