Working 1-Watt 50mm LED
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Hello fellow makers,
Have you ever worked with a 5MM LED and wished it had just a little more light output?
Introducing the 50MM LED!
10 times BIGGER...
10 times MORE OUTPUT...
And they said bigger isn't always better!
Let's start making your own...
What You Will Need:
To make this project you will need the following:
- 2 part deep casting epoxy resin
- Access to a 3D printer for the mold
You can also make the mold by hand if you don't have access to a 3D printer eg. Carving it out of polystyrene.
- 1W White LED
- 4mm Brass/bronze rods
- 1mm Brass/bronze plate
- Solder
- 4mm Wire
For the finished LED leads
- ~6mm Heat shrink
- Sanding paper
- Butane torch
-2 Part fast cure epoxy glue
Optional:
- Release agent
I used PVA release agent but this can be whatever is recommended by the epoxy manufacturer or even wax.
- Plating solution
- Power supply
- USB male connector
- Resistor
*As an Amazon Associate I receive a small percentage from sales made through provided links at no cost to you, this helps fund future projects.
Updates:
A big shout out to robertslassiter for showing me these DIY water globes that look pretty dang close to a 5mm LED, you could replace the entire resin lens with this or use them instead of the 3d printed mold and fill these up with resin to skip all the prep work, sanding and spraying.
Get these over at > Amazon - DIY Water globe kit 4pcs
Design the Mold:
First we will need to design the mold that will be used to cast the lens of the LED.
I used Fusion 360 for this, the design is really simple and consists only of two circles that I extruded and then finished with a 25mm fillet.
Next I created a shell around the design to form our mold.
I later design a peg type holder that keeps the leads of the LED together whilst assembling.
Print the Mold:
After exporting the files to stl's I printed both parts in PLA.
If you can I would recommend rather printing the mold in either PETG or ABS filament as the heat generated by some resin when curing might cause the PLA to deform.
My print settings used were:
Material: Sunlu Grey standard PLA
Speed: 60mm/s
Layer height: 0.2mm
Temp: 230 deg C
Cooling: 100%
Nozzle: 0.6mm
No supports needed
Make the LED Components: the Reflector Cup
I had a couple of goes at making the reflector cup and this is the method that turned out the best.
I started with a 15mm brass pipe (but copper pipe would work the same and is easier to get hold of) cut to about 10mm in length.
Grab the pipe with some pliers and heat it up with a butane torch until it is glowing red then quench it in water, this will anneal it making it easier to shape.
Next I placed it onto the head of a ball point hammer and started shaping it around the ball point using another small hammer.
I repeated the annealing process when the metal got harder to shape, this also prevents it from cracking.
I continued until I had a cup that was nice and smooth.
Make the LED Components: the Posts
Now for the posts.
I started by cutting a 450mm 4mm brass rod in half for the two legs of the LED.
Next we need the anode and cathode plates that will be cast inside of the lens.
I also cut a small round piece out of the plate to create a bottom for the reflector cup.
For this I used a piece of 1mm thick brass plate that I cut a 30mm by 15mm rectangle from using a diamond Dremel cutting blade.
Then cut the rectangle in half diagonally about 2/3rd of the way as pictured.
Soldering:
Now with everything cut out we can start assembling the leads.
I first took some wet 220 grit sandpaper and just refined all of the edges and sanded away any obvious imperfections in the metal.
Next I started by soldering the bottom of the cup into place and sanding it flush, then solder the rest of the pieces together like in the picture.
Note that because it is such a large piece of metal you will need to keep the soldering iron on the piece quite a while until it absorbed enough heat for the solder to start flowing.
Optional: Plating
This is optional but does make it look like the real thing.
I plated mine using an old long out of production tin plating kit and had no luck in finding a similar kit on Amazon but they do stock the nickel plating solution that works just as well or you could even have a go at creating your own nickel plating solution.
Before plating I sanded both pieces and went over it with a rubber polishing bit just to get a smooth finish.
Make sure that the pieces are free from any oil residue before trying to plate them.
The Light Source:
Now for the most important part... The light!
I'm using a 1 watt cool white LED for mine.
I start by placing a small blob of solder on the inside of the reflector cup near the positive terminal, next making sure of the polarity of my LED chip I placed a drop of CA glue onto the underside of the LED and soldered it to the inside of the cup(the body of the cup is the positive connection).
Now for the negative connection I took a piece of nickel plated copper wire (but you could also use a single strand of wire from a stripped cable) soldered it to the LED's negative leg and then to the negative lead of our 50mm led.
To simulate the phosphor layer that is present in a white LED I used some clear fast set 2 part epoxy mixed with a drop of lime yellow paint and filled the cup with it.
Prepping the Mold:
To get a better end result I decided to smooth out the mold a little.
Start with a coarse 220 grit sandpaper and smooth out the inside of the mold then move to a 400 grit and get rid of the scratches left by the 220 grit.
Next I aligned the two parts of the mold and stuck them together with some painters tape.
I used play-doh to fill in the seam in-between the two halves to prevent the epoxy resin from leaking out.
Now we need to give our mold a good coat of release agent and leave it to dry.
Casting the Lens:
It's time to cast the lens!
With the lead holder attached position the cup in the centre of the mold, I used a drop of glue on the holder to prevent the leads from moving.
Now mix up approximately 150 grams of resin according to the manufacturers instructions and let it stand to let the air bubbles introduced into the mixture while mixing rise to the top.
When your resin is clear slowly start pouring it into the mold until it is full, I tilted my mold slightly so that trapped air in the cup could escape.
You can pop any air bubbles on the surface using a butane torch.
Set aside to cure completely.
Sand and Paint:
After 24 hours curing it's time to pop it out of the mold.
Unfortunately mine had a bubble on the top of the lens due to a small leak, luckily this was an easy fix with some quick set epoxy.
Time to grab some 220 grit sandpaper and soapy water and sand away those pesky layer lines, after the 220 we can move to 400 grit to smooth it out and get rid of any scratches.
Next we need to apply a layer of clear lacquer, this will give you a crystal clear lens and protect the resin from UV rays that will eventually turn it yellow.
I mixed up a small amount of clear coat in my airbrush but a can will work just as well.
Spray a few layers until you have a nice even layer over the lens.
Leave to dry completely.
Adding the Finishing Touches:
Next I soldered some 4mm red and black wires to the legs and covered the joint with heat shrink.
To the ends of the wire I connected a male USB connector and current limiting resistor so that I have can just plug my new lil' LED lamp in anywhere.
Enjoy!
