DIY Mini Fridge Is Pure Brilliance In Foam

There’s nothing more pleasing on a hot day than an ice-cold beverage. While the vast majority of us have a fridge in the kitchen, sometimes it’s desirable to have a further fridge in the lab, games room, or workshop. To that end, you may find value in this ultra-cheap, low-cost DIY fridge build from [Handy_Bear].

Like many tiny fridge builds, this design eschews complex gas-cycle refrigeration techniques for simple Peltier modules. These are devices that have one cold side and one hot side, because they move heat when electricity is applied. This build uses a Peltier module fitted with a fan to better shift away heat from the hot side, improving the module’s cooling ability.

The “fridge” itself is assembled out of thick XPS insulation foam. A hot wire cutter was used to cut several slabs which were then assembled using hot glue. The Peltier module is installed on the back, at the top of the fridge. Thus, air which is cooled in this area will then travel down through the rest of the fridge’s cavity. [Handy_Bear] also goes over how to produce a working hinge and a gasket for the door, which helps with ease-of-use and efficiency. As a nice touch, a set of 12V LED lights are also installed inside, which light when the door is open. Just like the real thing!

The final build is noisy, slow to cool down, and it uses 60 watts of power to cool down just two regulation-sized sodas. Notably, you could fit two standard NATO smoke grenades in the same space, as they’re almost-identically sized (ask us how we know). However, smoke grenades don’t usually need to be refrigerated.

None of that means it isn’t fun though! Plus, [Handy_Bear] notes that adding a second Peltier would greatly aid the fridge’s ability to quickly chill your grenades sodas. You might even like to explore the use of special fan designs to make the fridge even quieter! Video after the break.

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Beverage Holder Of Science

The folks at [K&J Magnetics] have access to precise magnetometers, a wealth of knowledge from years of experience but when it comes to playing around with a silly project like a magnetic koozie, they go right to trial and error rather than simulations and calculations. Granted, this is the opposite of mission-critical.

Once the experimentation was over, they got down to explaining their results so we can learn more than just how to hold our beer on the side of a toolbox. They describe three factors related to magnetic holding in clear terms that are the meat and bones of this experiment. The first is that anything which comes between the magnet and surface should be thin. The second factor is that it should be grippy, not slippy. The final element is to account for the leverage of the beverage being suspended. Say that three times fast.

Magnets are so cool for anything from helping visualize gas atoms, machinists’ tools, and circumventing firearm security features.

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I Got 99 Volts And My Anodizing’s Done!

anodizing-titanium-with-coke

[POTUS31] had a need for anodized titanium, but the tried and true “submersion” method was not going to work out well for what he was trying to do. In order to create the look he wanted he had to get creative with some tape, a laser cutter, Coke, and a whole lot of 9v batteries.

His Ring-A-Day project has him creating customized rings based on reader feedback, and lately the requests have had him searching for a good way to color metal. Anodizing titanium was a sure bet, though creating detailed coloring on a small medium is not an easy task.

[POTUS31] figured that he could gradually anodize different areas of the ring by using laser-cut tape masks, allowing him to selectively oxidize different portions of his creations as he went along. Using the phosphoric acid prevalent in Coke as his oxidizing agent along with a constantly growing daisy-chain of 9-volt batteries, he had a firm grasp on the technique in no time. As you can see in the picture above, the anodizing works quite well, producing vivid colors on the titanium bands without the need for any sort of dye.

[POTUS31’s] favorite color thus far? A rich green that comes from oxidizing the metal at you guessed it – 99 volts.

[via Make]