Cordage - Palm fibre twine

I made string today out of the fibres that my very tall palm tree makes leaves out of.

It looks like this, and is surprisingly strong.

Not strong like really thin 80lb fishing line is strong, but strong like brown string is strong.

I think the natural brown string is made from hemp. And I would say this home made version is about a quarter of the strength of store bought brown string.

A quick search tells me the Japanese make palm fibre twine, and you might have seen it used for Japanese themed bamboo fencing to lash different lengths of bamboo together. It's dyed black in Adelaide's Japanese garden. .

The fibres look like this when in their natural state, and come from the flared out section where the frond meets the trunk.

The dead leaves stay hung up in the tree until a windy day deposits them all onto the BMW next door.

I still haven't made more than a foot long length of the stuff, so what I've made has no real value for tying stuff up, but as soon as I can arrange a lesson from my brother, I'll post up a how to.

When I was a kid in Papua New Guinea, my family owned a fishing net shop. Some of the locals would buy our green string (as seen in this post on making a blow dart), because it had great fibres, but they didn't like the string for some other reason. They would pick it apart and then rebuild it into string to make string bags known as Bilum.

Their string was substantially better than my string.

I'm going to get better at it until I can make some useful string, and then make that into useful rope.

120 Things in 20 years might take a while at getting better at this, because some of my favourite people gave me a Ukulele for my birthday.

Epic adventurer - Solar boat trolling motor

I got one step closer to setting out on my zillion mile epic adventure on the mighty Murray river, on my little solar powered boat.

That step included testing just how much juice I was going to need to run the trolling motor, and seeing if the solar panel I have will provide enough.

My boat is a displacement hulled catamaran. That means it doesn't do the skimming across the top of the water thing that most other racing cats do, so it's very outdated for racing, but it floats well, and the hulls are very low drag.  At their widest, they measure only 20cm or so. They are 4.2m in length, so they slide through the water without a lot of effort. Probably even slicker than a kayak.

The result of all this is that I can tick along at walking pace with an electric trolling motor on it's slowest setting.

I like walking pace.

In fact, aside from jet aircraft pace, and insane motor bike pace, walking pace is my favourite pace.

So I think, the result of all that is that I should be able to power my little boat with my single solar panel. That question has been nagging at me for ages. My solar panel says it delivers a maximum of 230w at 37v and also mentions 7.5 amps or so.  I think that means that at 12 volts after an MMPT solar charge controller, it will offer the battery a maximum of 19 amps. Probably much less.


I just put my trolling motor in a bucket of water (large bucket) and ran it through my multimeter. As far as I can tell, it draws around 12 amps on the lowest speed setting. I'll be taking a 120 amp hour deep cycle lead acid battery. From memory, before I had the solar panel, that battery gave around 5 hours cruising when I ran it down to 11v. But my memory is terrible for stuff like that.

Also as far as I can tell, I think that means I should be able to cruise for a reasonable amount of time each day. There's also the option of running a bit faster during the middle of the day, when my solar panel is generating the most power. It would be nice to leave the battery with a healthy amount of charge at the end of each day so that I could use some for light, charge my phone and UHF radio, and to power a laptop so I can get some blog posts out.

I'll probably want to set up camp each afternoon when there is still plenty of light, and get up early each morning to pack up camp and get under way when the river is at it's best. If I leave a full battery at the end of each day, I should be able to set off at first light, and then make up the charge by the end of the afternoon.

Or something.

But I have no idea how this will all pan out in the real world.

What I need is a 36v to 12v MMPT solar charge controller that actually works, and wasn't sold to me fraudulently by that trader on E-Bay.

Now I don't trust the world any more.

But I'll probably get over it.

But on the up side I now know how much current my little trolling motor draws, and I've also found a brand new way to inject a lot of oxygen into my fish tank very quickly, and perhaps mince fish.

Which is nice.

This is the trolling motor on it's highest speed setting.

Excited water.

120 Things in 20 years thinks it's found the worlds fastest way to empty a large bucket of water all over itself and it's shed, without actually picking it up and tipping it over itself.

Projectiles - Dart cannon

I thought I'd make a cannon, and use the little dart I made when I built my blow dart gun with a laser sight as the projectile.

Making projectile launching things that shoot projectiles can be fun.

And stupid.

This project was both.

I started with a jumbo bag of party poppers.

They might be called something different where you live, but they are a little explosive device designed to deliver a quantity of litter into the environment.

They do it surprisingly effectively.

I pulled all the streamers and other junk out to reveal the small firework.
Then it was a simple matter of finding a tube that would fit over the bit that goes bang.

I found a bic pen worked a treat, and the tapered end meant it was easy to create the required seal by just forcing it into the handle of the popper, to surround the firework.

Like this.

Before jamming the pen into place I put the dart in at the firework end.

And this is where the stupid bit comes to the fore...

Then I pulled the string.

Luckily I had taken the precaution of wearing a scratched pair of sunglasses, and aiming in the general direction of the back wall of my shed (garage/iron clad building full of junk in my backyard).

The result was that I no longer own my little hand made blow gun dart.

It's gone now.

It's definitely still in the shed, but it really could be anywhere.

It went away really, really fast, and obviously didn't want to be found.

I think it must hate me.

The pen/cannon has a new fracture as well. You can see it in the milky burnt picture in the pic before last.

I put the inky bit of the pen loosely into the little cannon and re-loaded it to see how much power it had, and was a little surprised to see it actually shift it ... perhaps....6 feet.

That could come in handy if you ever needed to project a full stop to the far wall of whatever room you were in.

Very handy.

According to my calculations, all this means I could shoot a 44 magnum slug nearly a thousandth of an inch.

Which is nice.

Generally I prefer to blog about things that are kid friendly, but this time I guess I have to say...

Don't try this at home...

Unless you really, really want to.

But please, please, put on an old pair of sunglasses or some safety goggles, or wrap your kids in a mattress or something. And maybe just launch a polystyrene ball from a bean bag or a pug of potato or something. It's always embarrassing to rock up to emergency with a little dart poking into your kid's brain through one of the soft, squidgy, eye portals that the gods built into heads as a sick party joke to make you look silly when you rock up to emergency with a little dart poking into your brain.

Don't encourage them.

Besides, wearing safety goggles shows you and your kids that you at least have a certain confidence in your ability to create mayhem.

I count the cannonic loss of my little home made blow gun dart a total success.

120 Things in 20 years thinks it might be a good time to quit while I'm ahead. I can see making cannons is a thing I could rapidly get addicted to. Like crack and cross-stitch, some things are (apparently) too addictive to mess with.

Just say no.


Projectiles - Building a blow gun with laser sight

I thought I'd build a blow dart gun with a laser sight.

It turned out to be a total success.

It works well, and is much more fun than regular darts of the non-blown variety.

I started with a couple of pins, some string, some cotton, and a thin pipe. A broken car aerial works well, so does a pen casing. Even a drinking straw works at a pinch. The longer the better, and it's best to avoid flexible things as your pipe. Drinking straws tend to be a little less accurate.
I started by piercing the string so I had four strings stuck to my pin.

 I taped up the strings so they wouldn't move when I started to wrap them.

This next bit is really important.

Add a loop of cotton running the length of the pin.
Take some cotton and wrap it tightly to make a binding along about a third of the length of the pin.

I also made one where I used electrical heat shrink instead of cotton binding. It worked well, and was much faster to make, but didn't look as nice as one with binding.

Trying to tie off  the end of a binding is difficult unless you have that loop we added.

To finish your binding, pass the loose end through the loop.

Then pull the back of the loop all the way back. This will draw in the lose end, and secure it by tucking it under itself... under the binding.

That's really important string tech. As long as you plan it beforehand and add that loop it's easy, but without the loop, it's next to impossible.
 The end result looks something like this.
Next I took another pin and frayed the string.

Wool would work better, but I didn't have any.
When it's fully frayed, it looks like this.

You can us it like this, but it was a little slow, and not very accurate.

I trimmed mine down a bit.

The point of the tail is to create drag so it flies straight, and with the sharp end up the front where it belongs.

If you have even one thin strand longer than the others it can cause trouble.

A long strand will make your dart turn off course a bit, and can also get stuck between your lip and the tube, resulting in a blowing noise but no shooting.

An easy way to trim it is to put it into the blow pipe and cut any excess with scissors.
Next, I found my container full of prototyping plastic. I explain it in this post about it's possible use in making hand made fishing lures, but basically it's stuff that gets soft at 65 degrees centigrade or so, and sets hard once it cools.

Next, I got hold of a laser pointer ($15 or so), then it was a simple matter of heating up some prototyping plastic, and wrapping it around both the tube, and my laser pointer.

I added three screws that sit through the plastic so I can tighten them against the laser to adjust where it points in relation to the tube. That way, it's easy to adjust and make certain everything lines up properly.

I shot some video while I was sighting it. I placed the laser sighted blow dart gun in a clamp, and repeatedly shot it, and adjusted the screws to get it more accurate. A simple matter of firing, then moving the dot to the same spot as the dart hit.

Thinking - Theoretical economic Anthropology and the Gold (star) Standard

One of the problems I see in the western world is it's dependence on reward.

The internet seems a little better than the real world in this respect, but I suspect it's because we don't see the takers doing the taking. We just see the givers being generous. The nature of the stuff up for grabs means that if you take more than you give, there's still exactly the same amount left for everyone else. Open source software is a good example. 

I've taken much, much, more from the net than I can ever give, but all the stuff I've taken is still there. 

Which is nice.

But in the real world you take some stuff, and there's not as much left for the next in line. And sometimes there isn't even a line*.  I've been lucky enough to have spent my formative years living in Papua New Guinea. To say anything about Papua New Guinea is to be wrong about most of it, but I'll say some stuff about it anyway. 

When I was in Papua New Guinea, I was there at a time when the locals were making the transition from the cultures and lifestyles they had been enjoying for the last few dozen centuries, to one that looks and tastes a little more like you might expect in a western city. One of the problems with shifts like this is the clash between the old economic system and the new. From this point is should be noted that when I talk about some attribute of Papua New Guinea's culture, I refer to only the bit's I know. There are something like a third of the worlds languages (or something) don't quote me)). and many more cultural ... things... paradigms? Anyway. every few hundred people are different. They talk different, they look different, they believe different, and they think different. Not just different as compared to me, but different from all the other different groups. I knew a fishing net merchant who could easily pick a persons birthplace to within a hundred kilometres or so, just by meeting them over the counter. Often with much greater accuracy to the point where they could name the village. Anyway...   One of the most interesting things about the culture clash was the gradual decline in the worth of generosity. Or at least my perception of that decline. There seemed to be some kind of social credit that a person could gain by simply giving stuff away. You might get something back from acts of generosity, but it might not come from the person you gave things to. You still see this in the west in small groups, but once you get to a certain population level, one where everybody can no longer know everyone else, the system breaks down. There comes a point where giving stuff away is no longer useful. 

And here I come to my point...

When you're little, you gain respect and trust within your family and friends, you are rewarded with new responsibilities, freedoms, and smiles. 

You don't need gold stars gummed to your work. 

I think gold stars (or points for Hufflepuff) might be encouraging our kids to seek only monetary reward, or perhaps an Oscar. 

I think we should stop it. 

120 things in 20 years thinks the best part about not being an academic, is that I have no need to quote sources, and I get to say whatever I want. 

*A line has just one characteristic. It's endedness. Two** ends, but just one characteristic. A list of people who can make the most noise from lowest volume to highest could be seen as another line, and often making the most noise gets you first grab at whatever's going. (see baby birds in nests, and political lobbyist)

** a circle is a line with no end. I guess that means I mean a "queue".  

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