Sometimes you just want some really big LEDs! It's no problem to go out and buy some that are slightly larger than your standard 5mm LED, but if it's something larger that you desire for a project then the quick and easy solution is, as always, hot glue. It's a fairly straightforward and inexpensive process, with the possible exception of finding an appropriately-shaped ice cube tray for the casting process. The LEDs look quite cool when lit up and add personality to any projects that have exposed lighting.
I made this project over at TechShop (http://techshop.ws/).
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Step 1: Materials
This is a pretty cheap process, which is great because these giant LEDs can be easily mass produced.
List of materials:
1 5mm (or larger) LED
1 ice cube tray- I used this one specifically because of its shape and the rubber bottom that allows you to easily poke the LED out, but any old ice cube tray will work if you're willing to use a knife or similarly small object to pry the glue out.
Hot glue/hot glue gun
1 X-Acto knife
1 paper towel
Step 2: Preparing the Ice Cube Tray
The obvious problem that comes up with any sort of hot glue casting is that, being an adhesive, once it grabs onto something it will let go only begrudgingly. If you just dump a bunch of hot glue into the tray you'll have a heck of a time trying to retrieve it- believe me. That's why it's necessary to lubricate the surface with something slick- corn oil in this case, as it's easy to wash off- so that removing the final product is as painless as possible. Just dampen a paper towel in the oil and go to town!
I make sure to use an extremely liberal amount of corn oil; too little and you might find yourself in trouble. Again, speaking from experience.
Step 3: Unleash the Glue
Now begins the gluing. Let's start with the hot glue gun: if you have a larger gun with a Low/High heat setting, set it to Low. That way the bond won't be as strong and it'll be easier to remove. If you have a miniature gun with one setting then it's probably equivalent to the Low setting and you're good to go.
You're going to fill one of the ice cube... holes(?) almost entirely full with hot glue, at which point you'll dip in an LED until the plastic tip is fully covered. The glue will still be a liquid so you'll have to hold the LED in place as it dries so that it doesn't sink to the bottom.
Step 4: Clean Up and Test!
After the glue has dried it's time to remove it. If you used enough corn/vegetable oil then it should pop right out, either by pushing on the bottom if your ice tray has rubber bottoms or by using a slim object to pry it out. It's likely that there'll be some thin and thick strands of glue along the bottom where it may have overflowed; best to trim this off with a small blade.
After that, just plug it in as you would any other LED and let it shine! It lights up surprisingly well given how much material there is over the starter LED. Rinse the oil out of the ice tray, unplug your glue gun and that's about all there is to it!