Reviving Old Recipe For Faraday Wax Keeps Vacuum Experiments Going

Science today seems to be dominated by big budgets and exotics supplies and materials, the likes of which the home gamer has trouble procuring. But back in the day, science was once done very much by the seats of the pants, using whatever was available for the job. And as it turns out, some of the materials the old-timers used are actually still pretty useful.

An example of this is a homemade version of “Faraday Wax”, which [ChristofferB] is using for his high vacuum experiments. As you can imagine, getting a tight seal on fittings is critical to maintaining a vacuum, a job that’s usually left to expensive synthetic epoxy compounds. Realizing that a lot of scientific progress was made well before these compounds were commercially available, [ChristofferB] trolled through old scientific literature to find out how it used to be done.

This led to a recipe for “Faraday Wax”, first described by the great scientist himself in 1827. The ingredients seem a little archaic, but are actually pretty easy to source. Beeswax is easy to come by; the primary ingredient, “colophony”, is really just rosin, pretty much the same kind used as solder flux; and “Venetian red” is a natural pigment made from clay and iron oxide that can be had from art suppliers. Melted and blended together, [ChristofferB] poured it out onto wax paper to make thin strips that are easily melted onto joints in vacuum systems, and reports are that the stuff works well, even down to 10-7 mbar.

We love this one — it’s the perfect example of the hacker credo, which has been driving progress for centuries. It also reminds us of some of the work by [Simplifier], who looks for similar old-time recipes to push his work in DIY semiconductors and backyard inductors forward.

[David Gustafik] dropped us the tip on this one. Thanks!

Cocktail Of Chemicals Makes This Blueprint Camera Unique

When you’re looking at blueprints today, chances are pretty good that what you’re seeing is anything but blue. Most building plans, diagrams of civil engineering projects, and even design documents for consumer products never even make it to paper, let alone get rendered in old-fashioned blue-and-white like large-format prints used to produced. And we think that’s a bit of a shame.

Luckily, [Brian Haidet] longs for those days as well, so much so that he built this large-format cyanotype camera to create photographs the old-fashioned way. Naturally, this is one of those projects where expectations must be properly scaled before starting; after all, there’s a reason we don’t go around taking pictures with paper soaked in a brew of toxic chemicals. Undaunted by the chemistry, [Brian] began his journey with simple contact prints, with Sharpie-marked transparency film masking the photosensitive paper, made from potassium ferricyanide, ammonium dichromate, and ammonium iron (III) oxalate, from the UV rays of the sun. The reaction creates the deep, rich pigment Prussian Blue, contrasting nicely with the white paper once the unexposed solution is washed away.

[Brian] wanted to go beyond simple contact prints, though, and the ridiculously large camera seen in the video below is the result. It’s just a more-or-less-lightproof box with a lens on one end and a sheet of sensitized paper at the other. The effective ISO of the “film” is incredibly slow, leading to problematically long exposure times. Coupled with the distortion caused by the lens, the images are — well, let’s just say unique. They’ve got a ghostly quality for sure, and there’s a lot to be said for that Prussian Blue color.

We’ve seen cyanotype chemistry used with UV lasers before, and large-format cameras using the collodion process. And we wonder if [Brian]’s long-exposure process might be better suited to solargraphy.

Continue reading “Cocktail Of Chemicals Makes This Blueprint Camera Unique”

Acrylic Mold Makes For Professional-Looking Silicone Keyboards

The border between consumer electronics and DIY projects is getting harder and harder to define. First it was PCBs, which quickly went from homemade to professional with quick-turn services. Then low-cost CAD/CAM packages and high-end fabrication services gave us access to enclosures that were more than black plastic boxes with aluminum covers. Where will it end?

That’s a question [arturo182] begins to answer with this custom-molded silicone keyboard for a handheld device. There’s no formal writeup, but the Twitter thread goes into some detail about the process he used to make the tiny qwerty keypad. The build started by milling a two-part mold from acrylic. Silicone rubber was tinted and degassed before injecting into the mold with a baster. The keys are connected by a thin membrane of silicone, and each has a small nub on the back for actuating a switch.

There’s clearly room for improvement in this proof of concept – tool marks from the milling process mar the finish of the keys slightly, for instance. There may be tips to be had from this article on silicone keyboard refurbishment to improve the process, but overall, we’d say [arturo182] is well on his way here.

The Blackest Black, Now In Handy Pocket Size

If you thought “carbon nanotubes” were just some near-future unobtainium used in space elevators, don’t worry, you certainly aren’t alone. In reality, while the technology still has a way to go, carbon nanotube production has already exceeded several thousand tons per year and there are products you can buy today that are using this decidedly futuristic wonder material. Now there’s even one you can put in your pocket.

Created by [Simon], a designer in the UK, this small carbon nanotube array is described as “A simulated black hole” because the surface absorbs 99.9% of the visible light that hits it. Protected by a clear acrylic case, the sample of the material makes a circle that’s so black it gives the impression you’re looking into deep space. Unfortunately, no time-dilating gravitational forces are included at any of level of support in the ongoing Kickstarter campaign; but considering it was 100% funded in just a few hours, it seems like most people are OK with the trade-off.

[Simon] is well aware of the ongoing war between different methods of creating the “Blackest Black”, and he thinks he’s put his money (and by extension, his backer’s) money on the winner. Singularity is using a similar technology to the exclusively-licensed Vantablack, rather than a super-dark paint like “Black 3.0”. In fact he’s so confident that Singularity will appear darker than Black 3.0 that he mentions a head-to-head comparison is currently in the works.

If there’s a downside to the carbon nanotube array used in Singularity, it’s that you can’t actually touch it. [Simon] warns that while the acrylic case is only held together with magnets and can be opened for more careful inspection, actually touching the surface is absolutely not recommended. He says that even dust getting on the material is going to adversely effect its ability to absorb light, so you should really keep it buttoned up as much as possible.

While the Singularity looks like an interesting way to experience near perfect blackness, the concept itself is far from a novelty. A material that can absorb essentially all the light that hits it has important scientific, military, and of course artistic applications; so figuring out how to pull it off has become a pretty big deal.

Carbon Quantum Dots In Your Favorite Color

Citizen scientist extraordinaire [Thought Emporium] put out a new video about colorful quantum dots which can be seen below the break. Quantum dots are a few nanometers wide and you can tell which size they are by which color they fluoresce. Their optical and electrical properties vary proportionally with size so red will behave differently than purple but we doubt they will taste like “cherry” and  “grape.” Let’s not find out. This makes sense when you realize that a diamond will turn into black powder if you pulverize it. Carbon is funny like that.

[Thought Emporium] uses the video for two purposes. The first is to demonstrate the process he uses to make different size quantum dot in his home lab. The second purpose is to implore the scientific community, in general, to take better care when publishing scientific papers. A flimsy third reason is to show that the show must go on. Partway through, all the batteries for his light were dead so he hastily soldered a connection for his benchtop power supply.

We’ve mentioned [Thought Emporium] a few times before. Another of his carbon-based experiments involved graphene creation. How about magnetic DNA extraction? [Thought Emporium] did that too. If you can’t get enough magnets, how about implanting one?

Continue reading “Carbon Quantum Dots In Your Favorite Color”

Retrotechtacular: Turn On The Magic Of Colored Light

title cardChances are, you take color for granted. Whether or not you give it much thought, color is key to distinguishing your surroundings. It helps you identify fire, brown recluse spiders, and the right resistor for the job.

In the spotlight this week is a 1950s educational film called “This is Color“. It also happens to be a delightful time capsule of consumer packaging from the atomic age. This film was made by the Interchemical Corporation, an industrial research lab and manufacturer of printing inks. As the narrator explains, consistent replication of pigments is an essential part of mass production. In order to conjure a particular pigment in the first place, one must first understand the nature of color and the physical properties of visible light.

electromagnetic spectrumEach color that makes up the spectrum of visible rays has a particular wavelength. The five principal colors—red, yellow, green, blue, and violet—make possible thousands of shades and hues, but are only a small slice of the electromagnetic spectrum.

When light encounters a transparent material more dense than air, such as water or glass, it has to change direction and is bent by the surface. This is known as refraction. A straw placed in a glass of water will appear bent below the surface because the air and the water have different refractive indices. That is, the air and water will bend or refract different percentages of the light that permeates them. Continue reading “Retrotechtacular: Turn On The Magic Of Colored Light”

Direct To PCB Etch Resist Printing

Here’s a step-by-step guide for printing etch resist directly to copper clad boards. Two methods of making printed circuit boards at home have long dominated as the favorites; using photo-resist, and the toner-transfer method. The latter involves printing board artwork on a laser printer and then ironing it onto the copper clad. We’ve seen some efforts to print toner directly to the copper, or to use ink to adhere toner and then heat fuse it, but this hack is the first one we remember seeing that uses an inkjet printer directly.

The best reason inkjet printing isn’t often used is do to the ink’s iability to protect copper from the etchant. This method uses MISPRO ink that is pigment based and will resist the acid. An Epson Stylus Photo R260 printer was chosen because you can get refillable printer cartridges which work with the ink, and they’re fairly easy to modify. In order to feed substrate through the device it needs some physical alteration to make room for the thickness of the material, and an ATtiny13 has been added to trick one of the sensors.

Unfortunately we didn’t find photos of the printed resist. But there is source code available for the tiny13 if you do give this a try.

[Thanks Pavlejo]