I have recently seen stores decorating their fronts with old ‘Edison-style’ light bulbs like this one:
And so I tried to persue it but it was very hard to find and all I could find in the end was 110V antique bulbs and those only available online.
So, I set out on a project to make the most perfect looking incandescent element from scratch with easy-to-find stuff by hand.
With my understanding of Physics, I sourced the material to be used as the element, constructed it by hand and applied current to the element I made.
The results were spectacular. Not only did it light up quite brightly and looked more vintage than modern antique light bulbs, it also gave me a unique feeling of seeing my own craft work.
After the success, I did some trial and failure experiments and finally came to one optimal recipe — one that glows brightly and still is awesome to look at. So in this article, I am going to share with you how to make your own incandescent element (a coil that is made into a filament) and make it look awesome. At the same time, I will also share with you somethings based upon my past experiments so you do not have to do the hard work yourself.
Unlike a light bulb, I will not cover how to make an evacuated glass tube as it is pretty complicated to do in my region and will instead expose the element to oxygen (an oxidant) which will wear out the element and rendering it short-lived. To be honest, I have never seen mine break due to old age even with exposures to oxygen. However, it is best to contain the element in an evacuated glass tube to make it look even more awesome for a longer period of time and to reduce the chance of burning oneself with by touching the element directly or to reduce the chance of a fire that the element can cause, unless you want to use it for fire-starting or heating purposes.
The following project uses high current but low voltage electricity but those factors contribute to a considerably high power consumption. It also presents a fire hazard and can pose servere burns to tissues, so please treat it like a campfire — don’t leave it unattended, and children and immature individuals MUST be supervised and assisted by mature individuals while performing this experiment.
This guide assumes you have knowledge in Physics. To continue, you must agree that you are responsible for any losses, failures, damages and fatalities caused by performing this experiment and is thus not my fault — you probably did something wrong.
This guide is what I did for my project, you can change things at your own risk. But if you did everything right, then the result will be spectacular.
What you need
A high-current 24 volt power source (e.g. 2 car batteries that you took from your grandma’s mobility scooter. Your two batteries must have a large enough capacity to supply electricity to the coil during the switch-on surge and still keep delivering constant power afterwards — A23 cells won’t stand a chance.).
33 inches of the thinnest and finest iron wire you can find (Physics dictates how wire thickness, length, heat applied and electric current are proportional and how those factors can affect the amount of black-body radiation emitted. Please refer to that yourself if you want to understand the mechanics or want to use a different specification of wire. Safety remark: The wire must be long enough to offer a decent amount of electrical resistance to ultimately protect you from over-current. It must be thinner than any/the thinnest of all other circuit components (cables and batteries) to avoid any fatalities; thinnest in your hardware shop is best.).
Two heavy-duty copper cables (not including the cable that is used to connect two batteries together in series which must also be heavy duty. They must withstand high amounts of electrical current.).
Two fastening iron nails.
A hard cylindrical object of reasonable size to shape the iron wire into a coil (e.g. a cylindrical earth ground rod, a long fastening iron nail).
A high-current SPST switch (e.g. a 20A fused safety breaker; insisted for safety).
A fuse (e.g. a 10A slow-blow fuse; insisted for safety. May vary with different specifications.)
Take 33 inches of your iron wire (thick wires need to be longer) and wrap it around your cylindrical object neatly from the beginning of the wire to the end. Make sure that each round of the coil is spaced slightly and is spaced evenly to allow equal heat transfer between the rounds for greater and equal radiation output.
Insert each fastening nail on each end of the coil. Let the furthest round hold the nail.
Prepare your power source. Expect an 18A switch-on surge and a 6A continuous current draw (a slow-blow fuse will glow during the switch-on surge; this is to be expected). This amounts to a power draw of 432 watts surge peak and 144 watts continously.
Hook up the pole of your SPST switch to one terminal of your power source. Make sure it is in the open/off position.
Hook up your 10A fuse to the throw of your switch.
Hook up one end of one of the two of your heavy-duty cables to the 10A fuse which is hooked up to the throw of your switch. Hook up the other end of the same wire to one of the two of your fastening nail which is connected to your coil.
Hook up one end of the other of the two of your heavy-duty cables to the other terminal of your power source. Hook up the other end of the same wire to the other one of the two of your fastening nails which is connected to your coil.
Make sure you did everything correctly and neatly. Make sure you have a special space for your coil to rest upon. Make sure safety is priority. If anything looks wrong, you should correct it now.
If all looks right, flick the SPST switch to turn on the current and behold! Never leave it on unattended and never touch the incandescent element while it is hot. Use responsibly and with care for the environment.
Tips & Notes
- It is normal to observe a brief moment of arc discharges and a glowing fuse during the switch-on surge on a cold coil.
- Leave the coil, the fastening nail and the wires for at least 5 minutes before touching them so that they cool down enough to touch.
- Best viewed at night.
Wire length chart
My uncle wasn’t around, so I wrote that for my reference infront of his garage. 😛
I haven’t tested the life span of my coil, but I’d give it about 30 minutes without an evacuated glass tube. I think it could last 500 hours with a properly evacuated glass tube.