mylar

8 Articles

Mylar Space Blankets As RF Reflectors

May 15, 2025 by 11 Comments

Metalized Mylar “space blankets” are sold as a survivalist’s accessory, primarily due to their propensity for reflecting heat. They’re pretty cheap, and [HamJazz] has performed some experiments on their RF properties. Do they reflect radio waves as well as they reflect heat? As it turns out, yes they do.

Any antenna system that’s more than a simple radiator relies on using conductive components as reflectors. These can either be antenna elements, or the surrounding ground acting as an approximation to a conductor. Radio amateurs will often use wires laid on the ground or buried within it to improve its RF conductivity, and it’s in this function that he’s using the Mylar sheet. Connection to the metalized layer is made with a magnet and some aluminium tape, and the sheet is strung up from a line at an angle. It’s a solution for higher frequencies only due to the restricted size of the thing, but it’s certainly interesting enough to merit further experimentation.

As you can see in the video below, his results are derived in a rough and ready manner with a field strength meter. But they certainly show a much stronger field on one side resulting from the Mylar, and also in an antenna that tunes well. We would be interested to conduct a received signal strength test over a much greater distance rather than a high-level field strength test so close to the antenna, but it’s interesting to have a use for a space blanket that’s more than just keeping the sun away from your tent at a hacker camp. Perhaps it could even form a parabolic antenna.

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Solar Cell Fabric Makes Anything Solar

December 18, 2022 by 16 Comments

MIT has been working on very thin solar cells made of a film just a few microns thick. The problem? The cells are so thin that they’re hard to work with. You could make a small solar cell on top of, say, a glass slide, but that’s not all that interesting since you can make perfectly good solar cells that are as fragile as glass using conventional techniques. But in a new paper, MIT researchers describe creating 50-micron-thin fabrics that can generate electricity from solar.

The process still involves using chemical vapor deposition to produce the solar cell on glass. However, the cells are removed from the glass, prepared with electrodes, and then transferred to a piece of fabric which acts as a new substrate.

The fabric used in the paper is a composite fabric known as Dyneema composite fabric. It uses ultra-high molecular weight polyethylene fibers and sheets of Mylar. This material has low weight but a very high strength. A UV cure adhesive bonds the fabric and solar cells.

Honestly, we doubt anyone will be making these in their garages anytime soon. But we would love to see what you could do with a roll of this fabric. Wearables, self-charging laptop bags, or solar-powered instruments in an airborne drone could all take advantage of the material’s flexibility and low weight.

Fixing A Hot Shop, With Science

September 2, 2022 by 42 Comments

We know that pretty much everybody in the Northern hemisphere has had a hellish summer, and there’s little room for sympathy when someone busts out with, “Oh yeah? You think THAT’s hot? Well, lemme tell you…” But you’ve got to pity someone who lives in north Texas and has a steel Quonset hut for a shop. That’s got to be just stupidly hot.

But stupid hot can be solved — or at least mitigated — with a little smarts, which is what [Wesley Treat] brought to bear with this cleverly designed shop door heat shield. When it pushes past 42°C — sorry, that sounds nowhere near as apocalyptic as 108°F — the south-facing roll-up door of his shop becomes a giant frying pan, radiating heat into his shop that the air conditioner has trouble handling. His idea was to block that radiant heat with a folding barrier, but to make sure it would be worth the effort, he mocked up a few potential designs and took measurements of the performance of each. His experiments showed him that a layer of extruded polystyrene (XPS) foam insulation covered with reflective Mylar did better than just the foam or Mylar alone.

The finished heat shield is an enormous tri-fold plywood beast that snugs up against the door when things get toasty in the shop. There’s a huge difference in temperature between the metal door and the inside surface of the shield, which will hopefully keep the shop more comfortable. We imagine that the air between the door and the shield will still heat up, and convection could still distribute all that hot air into the shop. But at least he’s giving the AC a fighting chance.

In addition to great shop tips like this and his custom storage bins, [Wesley] is a talented signmaker. He’s pretty funny too — or maybe that’s just the heat talking.

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ElectriPop Turns Cut Mylar Into Custom 3D Structures

May 6, 2022 by 14 Comments

Mylar has a lot of useful properties, and as such as see it pop up pretty often, not just in DIY projects but in our day-to-day lives. But until today, we’ve never seen a piece of Mylar jump up and try to get our attention. But that’s precisely the promise offered by ElectriPop, a fascinating project from Carnegie Mellon University’s Future Interfaces Group.

The core principle at work here is fairly simple. When electrostatically charged, a strip of Mylar can be made to lift up vertically into the air. Cut that strip down the center, and the two sides will repel each other and produce a “Y” shape. By expanding on that concept with enough carefully placed cuts, it’s possible to create surprisingly complex three dimensional shapes that pop up once a charge is applied. A certain degree of motion can even be introduced by adjusting the input power. The video after the break offers several examples of this principle in action: such as a 3D flower that either stands up tall or wilts in relation to an external source of data, or an avatar that flails its arms wildly to get the user’s attention.

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Easy Parabolic Mirror From A Trash Can Lid

November 1, 2016 by 34 Comments

Parabolic reflectors for solar applications are nice stuff, and making your own is a great project in itself. One of the easiest ways we have seen is that of [GREENPOWERSCIENCE], who uses nothing more than a trash can lid, mylar film, and tape. You need a way to make a partial vacuum though.

The idea is so simple that it´s almost like cheating. Cut a circle of mylar slightly larger than the lid, and tape it all around, taking care of stretching the mylar in the process. After you´re done with this, you end up with a nice flat mirror. Here´s where the vacuum is needed to force the film into parabolic shape. Extract the air from a little hole in the lid that was previously drilled, and tape it to prevent the loss of the vacuum. The atmospheric pressure on the mylar film will take care of the job, and magically you get a nearly-parabolic reflector ready for work.

In this other video, you can see the reflector in action burning stuff. One obvious problem with this technique is the loss of the vacuum after some time, about an hour according to the author. Here´s another way to make a more durable mirror also with mylar as the reflecting element, however the quality of the resulting mirror is not as good.

 

Pressure-formed Parabolic Mirror From A Mylar Blanket

July 26, 2016 by 76 Comments

Parabolic reflectors are pretty handy devices. Whether you’re building a microwave antenna or a long-distance directional microphone, suitable commercial dishes aren’t that hard to come by. But a big, shiny mirror for your solar death-ray needs is another matter, which is where this pressure-formed space blanket mirror might come in handy.

Pressure-forming was a great choice for [NighthawkInLight]’s mirror. We’ve covered pressure-formed plastic domes before, and this process is similar. A sheet of PVC with a recessed air fitting forms the platen. The metallized Mylar space blanket, stretched across a wooden frame to pull out the wrinkles and folds, is applied to a circle of epoxy on the platen. After curing, a few puffs with a bicycle tire pump forms the curve and stretches the film even smoother. [NighthawkInLight]’s first attempt at supporting the film with spray foam insulation was a bust, but the later attempt with fiberglass mesh worked great. A little edge support for the resulting shiny taco shell and the mirror was capable of the required degree of destructive potential.

We doubt this process can be optimized enough to produce astronomy-grade mirrors for visible light, but it still has a lot of potential applications. Maybe a fiberglass radio astronomy dish could be pressure-formed directly with a rig like this?

Foam And Antistatic Bag Bring Vintage Compaq Keyboard Back To Life

September 26, 2015 by 19 Comments

After winning an online auction for an 1980s vintage Compaq Portable PC, [leadacid44] discovered why it only cost him $5USD – the keyboard was shot. Not willing to accept having forked out $45USD to ship a brick, he tore into the ancient machine and came up with a found-material solution to the wonky keyboard.

[leadacid44]’s very detailed writeup of the fix for his Compaq includes a thorough examination of the guts of the machine. He got it to boot to MS-DOS 5.0 off of a 20MB ISA hard drive card and began probing the keyboard problem. It turns out the Compaq keyboard has much in common with a modern touchscreen, in that it’s a capacitive keyboard. Unfortunately the foam disks used as springs under each key cap had degraded over the last 30 years, so [leadacid44] began a quest to replace them. After much experimentation and a few false starts, he created a sandwich of transparency film, closed-cell polyethylene foam, and a Mylar antistatic bag. Many discs were punched out with a leather punch and tediously placed in the body of each key switch, and the quick brown fox was soon jumping flawlessly over the lazy dog.

We’ve seen some fixes to these lovable luggables before, like this dumpster queen that became a Hackaday Retro submission. At least [leadacid44]s machine didn’t release the Magic Blue Smoke like that one did.