The Science of Strengthening Glass

Strengthen Glass

[Ben Krasnow] is at it again. This time he’s explaining a simple method for strengthening glass. As usual, he does a fantastic job of first demonstrating and explaining the problem and then following it up with a solution.

[Ben] first uses a simple rig to place a controlled amount of force against a glass microscope slide. His experiment shows that the slide shatters once about 30psi of force has been applied to the center of the slide.

[Ben] then goes on to explain that current methods for producing glass leave many tiny impurities, or cracks, in the glass. As the glass slide flexes, the inside edge is placed into a compression force while the outside edge is under tension. The glass is more easily able to handle the compression force. The tension is where things start to break down. The tension force eventually causes those tiny impurities to spread, resulting in the shattering glass.

One possible solution to this problem is to find a way to fill in those tiny impurities. According to [Ben], most glass has sodium added to it in order to lower the melting temperature. [Ben] explains that if you could replace some of these smaller sodium atoms with larger atoms, you could essentially “fill” many of the tiny impurities in the glass.

[Ben] does this himself by heating up a small vat of potassium nitrate. Once the powder becomes molten, he submerges the glass slides in the solution for several hours. During this time, some of the sodium atoms are replaced by potassium atoms due to the natural process of diffusion.

Once the slides have cooled down, [Ben] demonstrates that they become much stronger. When placed in the testing rig, the stronger slides do not break until the pressure gets between 60psi and 70psi. That’s twice as strong as the original glass. All that extra strength from such a simple process. Be sure to watch the full video below. Continue reading “The Science of Strengthening Glass”

Homemade Ball Mill Tumbles Along Like a Champ

[Mike] enjoys doing all kinds of things with glass. He likes to melt it and fuse it into new things, so it’s perfectly understandable that he wanted to make his own glass. Doing so requires finely ground chemicals, so [Mike] put together this awesome homemade ball mill.

The design is wonderfully simple. The mill is powered by a robust 12VDC motor from a printer that he’s running from a variable power supply in order to fine tune the speed. [Mike] built a scrap wood platform and attached four casters for the drum to spin against. The drum is rotated by a round belt he had lying around from various other projects. [Mike] already had a couple of those blue containers, which formerly held abrasive grit for use in vibratory tumblers.

[Mike] had some trouble with the drum walking off the casters so he attached scrap piece of aluminum to form an end stop. All he had to buy for this project were the 5/8″ steel balls and the casters. The mill can also be used as a rock tumbler, though the bottle isn’t quite water tight as-is. He does not recommend this type of setup for milling gunpowder or other explosives, and neither do we.

Make the jump to see the mill in action and get the grand tour. If you need more tumbling power, use a dryer motor!

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Building a Crystal Clear Whiteboard

[Michael Peshkin] teaches mechanical engineering at Northwestern University. He likes to use diagrams to illustrate his point, but he also likes to face his students when doing so. His solution was to develop this clear whiteboard which ends up unlocking a lot more than just some hand-drawn schematics.

It’s a bit hard to see what he’s written on the board in the image above but squint and see if you can figure out what’s wrong with this style of teaching? Everything he’s writing is backwards. That’s not actually a problem in this case as [Michael] uses flip teaching. He records and posts all of his lectures online. Classroom time is then used for question and answer on the lecture subjects. In order to get the text to read the correct way he just bounces the camera off of a mirror.

The board itself is a huge sheet of tempered glass attached to the metal frame using bolts through holes in the pane. This leave the edges free. He added extruded rail to the top and bottom to embed strips of LEDs. They light the inside of the glass, and excite the fluorescent dry erase marker ink making it much more visible. [Michael] didn’t stop with the board, he  also rigged up a lighting system that gives him a lot of options, and uses a monitor for dealing with digital overlays. He can put up a diagram on the computer, watching the monitor to see where his marker is making annotations. All this happens in real-time which means no post production! See a demo of these features after the break.

This could all be done without the glass at all, but that would make it quite a bit more difficult for the person doing the writing.

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Signmaking in glass and gold

glass

 

Signmaking today isn’t what it once was. Where today a few vinyl letters stuck to a piece of plate glass is good enough for any storefront, there was a time when the signs in front of businesses were works of art involving many skills and dozens of tradesmen to create. [David Smith] is one of the last remaining old-school signmakers, and his creations are just as beautiful as the finely crafted signs of a century ago.

The techniques [David] uses to create his signs are as varied as the finished products are elegant. He cuts patterned grooves into glass with wheels made of diamond or ceramic and bends shaped glass over forms in a very large kiln.

Aside from cutting, shaping, and grinding glass, [David] also paints his signs – on the back side in reverse, building up his design layer by layer. The very first layer in some of his designs are gold leaf, a difficult material but [David] invented his own leaf applicator that makes the job much easier.

Truly amazing works of art, and certainly much more elegant than whatever plastic nonsense goes as proper signmaking these days.

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Trimethyl Borate lantern built from garbage

scratch-build-lantern

This lantern was built from recyclable goods. It’s a bit dangerous when used like the image above, but [The Green Gentleman] does give you a few other options in his build instructions which make for much safer operation.

The lantern enclosure is made from old cans and a glass jar. He screwed a couple of boards together at a right angle to act as a jig for cutting the glass. The V-shape created by the boards holds the jar on its side, giving his glass cutting tool something to rest upon. He then turns the jar to score it around the top, and then bottom. He alternated pouring boiling and chilled water on the score mark to shock the glass into breaking along the line.

This makes up the clear part of the enclosure which is later mated with metal top and bottom pieces. From there he adds either an LED, an alcohol lamp, or the Trimethyl Borate lamp seen above. The first two are relatively safe, but the latter burns at around 1500 degrees F. We have reservations about using a plain old glass jar as the enclosure for something burning this hot. It really should be heat resistant glass.

21st century light bulbs using 3D printer and chemistry equipment

lab-equipment-light-bulbs

[Andreas Hölldorfer] brings his light fixtures into this century by using a couple of modern technologies. The fixtures combine LED modules, 3D printed pieces, and laboratory glassware to give his room a unique look.

The glass enclosure is something he’s had on hand for quite some time but they never actually got used. There is an opening at one end which is meant to receive a stopper. He modeled one including holes for the wires and printed the piece with a 3D printer. Also fabricated in the same way is a bracket that is used for mounting the fixture to the wall. The blossom of components inside the glass are each made up of five LED modules. There’s no word on what he’s using for a power supply or how he managed the cable runs, but he did post an image of two of the fixtures installed in his living room.

A concrete table with a little blinky built in

concrete-table-with-led-inlay

Members of the Warp Zone hackerspace wanted a coffee table that was beyond ordinary. They ended up pouring a concrete base for the glass top (translated). There were several things to address during the design. First off, they wanted to integrate LEDs in the concrete sides. Some consideration had to be made for portability as concrete is very heavy. The final piece of the puzzle was deciding what kind of hardware to place beneath the frosted glass.

The legs were designed with a large cut-out area to keep them as light weight as possible. The cross piece has a set of voids spelling out the name of the hackerspace with some green LEDs. This was accomplished by placing foam cut-outs of each letter in the forms before for concrete was poured. They sealed around each letter with silicone, but still had some seepage most likely caused when jostling the form to help remove air bubbles. Straws were placed in the foam to allow a cable pass through for the electronics. After everything was in place they filled the voids with hot glue to act as a diffuser.

There aren’t a lot of details about the RGB LEDs under the frosted glass. But you can see the light show they produce in the clip after the break.

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