Published on November 19th, 2014 | by Julie Finn2
How to Hollow an Incandescent Light Bulb
I know, I know… who still has an old incandescent light bulb in their house?
We do, sigh.
Our new house came to us chock-full of incandescent light bulbs, and we decided to let them burn out on their own before replacing them with the LED lights that we prefer. Fortunately, this hasn’t been taking very long–I’d forgotten how quickly an incandescent bulb burns out!
At least this new, limited supply of incandescent light bulbs has reminded me of how much I love to do projects with hollowed out light bulbs, and I’m happily at it again, this time teaching my kiddos, who one day will hardly remember what an incandescent bulb was like, how to craft with them, as well.
Before you can craft a project with a hollowed out incandescent light bulb, however, you first have to hollow the dang thing out!
How to Hollow Out an Incandescent Light Bulb
Gather your safety supplies. This project involves breaking things. Wear protective eye gear, because broken glass does not behave. I also put a giant old towel over my work surface to catch the teensy glass shards that are going to come flying out, and a glove on that hand that’s holding the bulb doesn’t hurt, either. Do you have band-aids nearby? It’s a 50/50 chance that you’re going to cut yourself.
While you’re gathering safety supplies, also gather your tools. You’ll need a wire cutter and a pair of needle nose pliers; both of these are the kind that you’d use in jewelry making, so hopefully you already have them or know someone who does.
1. Pry off the end cap. This is what connects the filament in the bulb to the power in the socket–it’s a very thin metal cap, and it’s easy to get the sharp edge of your wire cutters up under it and pry it off. Be gentle about it, because that black layer underneath it is glass, and it’s brittle.
2. Break off the glass insulation layer. The layer of black glass between the metal cap and the metal screw part of the bulb is easy to break–it’s also sharpy sharp, so be wary! The cleanest way to do this is to put one tip of the needle nose pliers into the hole in the middle of the black glass layer and pry. If you’re lucky, one whole side of the glass layer will break off neatly, and you’ll just have to pry off the other side.
If you’re not so neat about it, however, this is one of the parts of the project that can result in LOTS of tiny airborne glass shards. Just remember–blinding yourself while hollowing out your incandescent light bulb is not one of the stories that you want to have to tell on the lecture circuit.
3. Crack the glass tube inside. The filament is connected to a narrow glass tube that’s part of the bulb and comes all the way down to the metal screw part; you’re going to have to break off this narrow glass tube and pull it out.
To do this, hold the glass bulb gently but firmly in your non-dominant hand (got a glove on?), and use the point of the needle nose pliers in your other hand to tap around the edges of this tube, where it’s connected to the sides of the bulb. Gradually increase the force of your tapping, until you reach that sweet spot where you crack the glass but don’t shatter the entire bulb all over your table.
Crack all the way around the perimeter, then use the needle nose pliers to pull the entire filament fixture out of the bulb. Doesn’t it look super cool?!?
4. Grind down the sharp edges, and clean the glass. If you’ve got a Dremel, use it to grind down the sharp bits of broken glass around the interior edge of the bulb; otherwise, use a metal file.
Clean the glass bulb, inside and out, using the latter half of my cleaning old glass bottles tutorial–skip the boiling, in other words, but complete the steps involving the saltwater slurry.
There are LOADS of great things that you can do with a hollowed-out incandescent light bulb! In later posts I’ll show you my favorites, and show you the easiest way to craft an ornament hanger for all the light bulb ornaments that you’re going to want to make this year.