Heating, bending, and gluing to make acrylic enclosures


You can do a lot with acrylic and few tools. If you’re just starting out we’d suggest taking a look at [Michael Colombo’s] guide to heating, bending, and gluing to create custom acrylic enclosures. Chances are you already have most of what you need. The one tool you might be lacking is a heat gun.

The process starts with math. Before cutting the acrylic down to size you need to calculate how much you need. Next [Michael] demonstrates his cutting technique using a Dremel and a cut-off wheel. We prefer to clamp along the cut line, score many times with a razor knife, and snap the stuff. But you can also send it through a table saw if you have the right blade.

The bending technique he uses starts by clamping boards on either side of the bend. The acrylic left sticking out is pushed with a scrap board while the bend is heated with the heat gun. Once all of the corners were made in one piece the sides were glued in place. This last step can be tricky. The acrylic glue is made to work with perfect seams, so make sure your cuts are clean and the bent pieces line up.

The process was documented in the clip found after the jump. If you’re looking for a more targeted heat source check out this dedicated acrylic bender.

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Stocker monitors the markets


If you can’t help but spend the day checking in on your stock prices this ambient device can help you cope. It monitors how the trading is going and illuminates an LED as feedback. Here the Apple stock is trading up so the light is green. The video after the break shows other stocks trading down, causing it to switch to red.

An Arduino interfaces with the custom application via USB. For now it looks like the two colors are all it’s capable of but we think there’s a lot more potential. Some creative coding could use factors like how much the stock has moved, trading volume, volatility, or a plethora of other data to give feedback. We could see a spectrum of colors (like on a temperature map) used to improve the level of feedback. And if the market really tanks there’s always the ability to add flashing!

The diffuser for the project is quite interesting to us. [Ali Reza Kohani] made it from a leftover scrap of acrylic. The bubbled surface was created with a heat gun before bending the sheet into an arc.

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One method of fabricating translucent faceplates


Enclosures are the bane of electronics engineers (or so says [Dave Jones] of the EEVblog and The Amp Hour). But fabricating a case that looks great has been getting easier lately. [Eric Forkosh] produced this professional-looking translucent face plate with a minimum of effort. He found a way to use a laser cutter to etch icons in acrylic.

Admittedly, this is not very involved. But just look at the quality he achieved. The secret to his success (aside from having a quality laser cutter on hand) is to use high-temperature spray paint. The acrylic is coated in paint and allowed to dry before heading to the laser cutter. By using the rasterize setting under low power he kills two birds with one stone; the paint is etched away while the acrylic is left a little bit rough to act as a diffuser for LEDs behind the panel. [Eric] cautions against using regular spray paint. In his write up he shows off the unsightly results of doing so.

This makes a great addition to some of the case options out there. One that we have been keeping our eye on is the Sick of Beige initiative being spearheaded by [Ian Lesnet].

Silent HTPC build is an art piece for the livingroom


This sexy beast is [DeFex’s] new silent home theater PC. To give you an idea of scale, that motherboard is a Mini ITX form factor. Mounted below it is the solid state drive which is an SLC version chosen because they tend to last longer than the MLC variety. This distinction comes with a price tag that is $100 more expensive.

But we digress. It’s the custom case that really caught our eye with this build. The frame is made of a huge aluminum heat sink. It measures about 7″ by 10″ and sets the final foot print for the computer. An aluminum puck was added to transmit heat from the processor to the heat sink. Holes were drilled and tapped into the heat sink to accept the brass stand offs which hold the motherboard in place.

The near side of the case is a sheet of acrylic. It connects to the rest of the case using 3D printed brackets at each corner. There is an additional bracket on the bottom to hold the hard drive in place. The sides of the case are filled in with bicycle spokes which also find a home in the corner brackets. Now the hard part will be figuring out which orientation looks the best for displaying his fine craftsmanship.

[via Reddit]

Edge-lit musical birthday card

[Monirul Pathan] decided to make the card as unique as this gift when getting ready for a birthday. He designed and built his own musical card with LED edge-lit acrylic to display the message.

The electronic design seeks to keep things as flat as possible. The card-shaped acrylic panel has a void to fit the PCB exactly, and the components are relatively flat. One thing we found quite interesting is that the ATtiny85 which drives the device is surface mounted, but it is not a surface mount component. The layout includes though-hole pads, but instead of drilling holes [Monirul] clipped off the excess of the DIP legs and soldered the remainder directly to the copper. We suppose this isn’t going to get a lot of use so it just needs to hold together for one day.

As you can see in the video after the break, the speaker plays ‘Happy Birthday’ followed by ‘Under the Sea’. At the same time, four blue LEDs pulse to the music, lighting up the words that are engraved in the plastic.

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Hybrid rocket engine uses acrylic as fuel

We are fascinated by the hybrid rocket engine which [Ben Krasnow] built and tested in his shop. It is actually using a hollow cylinder of acrylic as the fuel, with gaseous oxygen as an oxidizer. We’re already quite familiar with solid rocket propellant, but this hybrid approach is much different.

When a rocket motor using solid propellant is lit it continues to burn until all of the fuel is consumed. That is not the case with this design. The acrylic is actually burning, but if the flow of oxygen is cut off it will go out and can be ignited later. This also opens up the possibility of adjusting thrust by regulating the pressure of the oxygen feed.

[Ben] milled the test rig in his shop. It’s a fat acrylic rod through which he bored a hole. There are two aluminum plates which complete either end of the chamber. The intake has a fitting for a valve which connects to the oxygen tank. There is a nozzle on the outflow end. Check out the video after the break to see a full description. You’ll also get a look at the toll the combustion heat takes on the rig.

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Make your own magnetic ink

Here [Catarina Mota] is showing off a ring of magnetic ink printed on a piece of paper. It’s strong enough to hold a disc magnet in place when the paper is raised vertically. This strength comes from mixing your own batch of ink.

Magnetic ink has been around a long time and is most often used in banking. The account number and routing number on the bottom left of paper checks are printed in magnetic ink to allow for automated recognition. Iron oxide is charged by the reader as it passes through. In this case, magnetite is used as the doping agent as it has very strong ferromagnetic properties. By mixing it with acrylic medium in a vortex mixer you end up with a homogeneous ink.

There’s a quick demo after the break that shows how well this printed ring holds the magnet. What are some things for which you would use this ink? Leave a comment to let us know.

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