For hackers in the Northern Hemisphere, the seasons of wet and cold are upon us. Staying dry is every bit as important as staying warm, so what better than a hack or two to keep us warm and dry! All you’ll need is a bed sheet, some rope, and a run to the local hardware store, and a bit of knowledge. [NightHawkInLight] has us covered with the excellent video “Recycled Bedsheets Make The Best Waterproof Tarps” as seen below the break.
[NightHawkInLight] brings old traditional methods into the 21st century by turning away from oil, beeswax and canvas in favor of a recycled bed sheet made waterproof with silicone. The video goes into just enough detail so that you can reproduce their results without fear of working with the powerful solvent being used.
Cheap hardware store grade silicone sealant is thinned by naphtha, worked into the old bed sheet, and then hung out to dry overnight. The result? A perfectly waterproof sheet that’s just as pliable as before treatment. But how can you use it like a tarp, when there are no eyelets? If you watch the video for no other reason, check out the neat attachment trick at the end, where traditional technology is brought to the fore once again with nothing more than a rock and a slip knot.
We can imagine that the uses for such inexpensive, durable home made tarps are many. Perhaps one could put it to use when building your own Custom Cycling Camper.
Seasoned Hackaday readers may have noticed over the years, that some of us who toil under the sign of the Jolly Wrencher have a penchant for older tech. After all, what’s not to like in a dirt cheap piece of consumer electronics from decades past that’s just begging for a bit of hardware hacking? For me at the moment this is manifesting itself in a selection of 8mm movie cameras, as I pursue a project that will eventually deliver a decent quality digital film cartridge.
When A Cell Is From West Germany, You Know It’s Old
“Made in West Germany”
The trouble with scouring junk shops for a technology superseded four decades ago is that the cameras I find have in most cases been sitting in a drawer since the early 1980s. They were a valuable item back in the day so of course they were hung on to, then they were forgotten about until one day the grown-ups who were once the kids featured in the home movies are clearing the house, and they start their journey to my bench.
The problem is that very few owners of 8mm cameras had the good sense to remove their batteries before putting them away, so I inevitably end up with a battery compartment full of crusty 1980s Duracells and rusted contacts. This has left me curious, just what has happened here and how can I fix it?
What’s The Leaky Stuff?
Construction of a zinc-manganese “alkaline” cell. Tympanus, Public domain.
Non-rechargeable cells come in a variety of chemistries, but the commercial ones we’re most familiar with are zinc-carbon “dry cells”, and “Alkaline” zinc-manganese dioxide cells. The zinc-carbon variety are becoming less common here in 2022 and have an acidic zinc chloride or ammonium chloride electrolyte, while the alkaline cells have a higher capacity and a basic potassium hydroxide electrolyte. They both have different failure modes that result in the leaky cells, so it’s worth taking a look at each one.
The failure mode of a zinc-carbon cell is a chemical one, the acidic electrolyte reacts with the zinc can anode, and eventually eats through it. The leaking electrolyte then attacks the surrounding circuitry and battery clips. It’s hardly a concentrated acid, but it’s enough to do plenty of damage over the years.
Meanwhile an alkaline cell has a build-up of hydrogen as it degrades. It incorporates a vent which allows the hydrogen to escape, however the hydrogen pressure can instead force the electrolyte out through this vent. The electrolyte will then corrode the battery terminals and any other electronics it touches. A feature of alkaline cell leakage is a white crust, this is potassium carbonate formed from the reaction between the potassium hydroxide electrolyte and carbon dioxide in the air.
The Global Parts Bin To The Rescue
Fresh and new battery clips for AA holders
How much damage has been done is usually a function of how long the leaking batteries have been in the device. Sometimes one is lucky and the battery contacts are salvageable, otherwise they are too far gone and a replacement has to be found. A past me tried all sorts of home-made solutions using stiff copper wire and other materials, but today thanks to the miracle of international commerce it’s usually possible to find a contact the same as or very similar to the old one. A quick AliExpress search on terms such as “AA battery spring” will return numerous options, and it’s simply a case then of paging through to find the one you need on the terms you like.
So those of you who like retro tech will find something familiar in the last few paragraphs, but there’s a lesson to be found in dealing with ancient batteries. Here in 2022 we’re more likely to have lithium polymer cells in our consumer devices and so the need to keep a pile of Duracells at hand is reduced. But the thought of today’s equivalent of a Super 8 camera lying forgotten in a drawer for decades with a cheap li-po pouch cell inside it is far more frightening than something with some crusty manganese cells. Have we just found the root cause of house fires in the 2040s?
Anybody born before the mid 1990s will likely remember film cameras being used to document their early years. Although the convenience of digital cameras took over and were then themselves largely usurped by mobile phones, there is still a surprising variety of photographic film being produced. Despite the long pedigree, how many of us really know what goes into making what is a surprisingly complex and exacting product? [Destin] from SmarterEveryDay has been to Rochester, NY to find out for himself and you can see the second in a series of three hour-long videos shedding light on what is normally the strictly lights-out operation of film-coating.
Kodak’s first attempt at a digital camera in 1975. The form-factor still left something to be desired…
Kodak have been around in one form or another since 1888, and have been producing photographic film since 1889. Around the turn of the Millennium, it looked as though digital photography (which Kodak invented but failed to significantly capitalize on) would kill off film for good, and in 2012 Kodak even went into Chapter 11 bankruptcy, which gave it time to reorganize the business.
They dramatically downsized their film production to meet what they considered to be the future demand, but in a twist of fortunes, sales have surged in the last five years after a long decline. So much so, in fact, that Kodak have gradually grown from running a single shift five days per week a few years ago, to a 24/7 operation now. They recently hired 300 Film Technicians and are still recruiting for more, to meet the double-digit annual growth in demand.
[Destin] goes to great lengths to explain the process, including making a 3D model of the film factory, to better visualize the facility, and lots of helpful animations. The sheer number of steps is mind-boggling, especially when you consider the precision required at every step and the fact that the factory runs continuously… in the dark, and is around a mile-long from start to finish. It’s astonishing to think that this process (albeit at much lower volumes, and with many fewer layers) was originally developed before the Wright Brothers’ first powered flight.
Pyramid salt crystals can grow naturally, and typically occur in locations where salt pools are undisturbed under the warmth of the sun. However, it’s possible to grow them on purpose, too. As a bonus, their hollow structure means they dissolve very quickly on the tongue, and can taste “saltier” than typical granular salt.
To grow your own, you’ll need a bag of salt, which is mixed with some water. You’ll want to do so in a glass dish, as the salty solution you’ll be making can ruin metal cookware. The dish can then be heated up on an electric hotplate, which is used to heat the solution to between 60 and 70°C.
A small amount of food-grade potassium alum is also added to the solution to calm the convection currents in the heated solution, allowing the crystals to form gently without sticking and clumping together. As the water boils away, the rectangular-pyramidal crystals grow.
Naturally, you must be careful before eating the results of any home-grown lab experiments. However, [Chase] reports having licked some of the crystals and has confirmed they do indeed taste salty. [Chase] also notes several ways in which the parameters can be changed to grow different types of pyramid crystals, too.
SLA 3D printing with resin typically means rinsing parts with IPA (isopropyl alcohol). That process results in cloudy, used IPA containing a high concentration of dissolved resin. The dual goals of cleaning and reusing IPA are important ones, and we have to say, [Jan Mrázek]’s unusual experiment involving a UV source and slowly-rotating paper tube to extract and cure dissolved resin might look odd, but the results are definitely intriguing.
Dissolved resin successfully pulled from IPA and cured onto a cardboard roll. This particular one rotated a bit too quickly, trapping IPA in the curing process and yielding a slightly rubbery wad instead of a hard solid.
The best way to dispose of liquid resin is to cure it into a solid, therefore making it safe to throw away. But what about resin that has been dissolved into a cleaning liquid like IPA? [Jan] felt that there was surely a way to extract the dissolved resin somehow, which would also leave the IPA clean for re-use. His solution? The device shown here, which uses a cardboard tube to pull dissolved resin from an IPA bath and a UV source to cure it onto the tube.
Here’s how it works: the tube’s bottom third sits in dirty IPA, and UV LEDs shine on the top of the tube. The IPA is agitated with a magnetic stirrer for best results. A motor slowly rotates the cardboard tube; dissolved resin gets on the tube at the bottom, UV cures it at the top, and the whole thing repeats. Thin layers of cured resin slowly build up, and after long enough, the roll of cured resin can be thrown away and the IPA should be clean enough for reuse.
So far it’s a pretty successful test of a concept, but [Jan] points out that there are still some rough edges. Results depend on turning the tube at a good rate; turning it too quickly results in IPA trapped with the cured residue. On the plus side, the UV source doesn’t need to be particularly powerful. [Jan] says that Ideally this would be a device one could run in a sealed container, cleaning it over one or two days.
Resin printing is great, but it’s a messy process, so anything that makes it less wasteful is worth checking out. Got any ideas for improving or building on this concept? If so, don’t keep ’em to yourself! Let us know in the comments.
A fountain is a great way of adding a little flair to an otherwise boring pond. All you need is a pump, a filter and some pipes, along with a nozzle to scatter the pressurized water in some aesthetically pleasing way. Fountains are generally quite safe: if any of the parts malfunction, the worst thing that can happen is some minor flooding.
How different this is for [Advanced Tinkering]’s recent project, the NaK Fountain. If this one were to spring a leak, it’s quite likely to take out its surroundings in a huge fireball. That’s because the fluid inside is an alloy of sodium and potassium in about a 1:3 ratio, known as NaK (pronounced like “knack”), which is a liquid at room temperature. Unfortunately, it’s also highly reactive: NaK oxidizes quickly when exposed to air and can even catch fire spontaneously. Contact with water will result in a fiery explosion that scatters corrosive liquids everywhere. Continue reading “A Liquid Metal Fountain That Works At Room Temperature”→
Making fermentation work for us is one of the original hacks that allowed humans to make food last longer, and festivities more interesting. [Mike G] has been experimenting with making his own vinegar, and found the end product to be a delicious addition to his cooking.
The first step is similar to making alcoholic beverages. Take something that contains sugar, like fruit, mix it with water and let stand. Wild yeast will feed on the sugar and create alcohol. Once the alcohol content reaches the 6-12% range, the resulting liquid can be separated from the solids and left exposed to the air. This allows Acetobacter bacteria to convert the alcohol into acetic acid, producing vinegar. The entire process takes around 30 days.
[Mike]’s first round of experiments was mainly with fresh fruit, with the addition of raisins. To prevent white mold from forming the mixtures should be stirred daily, but life got in the way and mold got out of control on all the fruits, except for the raisins. This gave [Mike] the to try another round with dried fruit, which was significantly less prone to mold, and produced deliciously flavored vinegar. [Mike] also demonstrated their use in a couple of mouth-watering dishes.
[NightHawkInLight] brings old traditional methods into the 21st century by turning away from oil, beeswax and canvas in favor of a recycled bed sheet made waterproof with silicone. The video goes into just enough detail so that you can reproduce their results without fear of working with the powerful solvent being used.
