Make Your Underwater Aquarium Light With Hot Glue!

About: Just a Small Tinkerer ;)

Hello Friends,
Today We will be Making An Underwater Led Light With Hot Glue!!
Who Ever Thought we could use Hot Glue to Make a underwater Light?

It uses 6-3Watt Leds ,1 (100Ohm)Resistor [Not Necessary] , Only Half Hot Glue Stick !

I am Participating in Budget Contest too as It uses Minimal Parts to make a Thing which is useable in many types like BathTube ,Showers , Fountains ,Aquariums,Outdoor Garden Light and many more.

Step 1: Get the Parts & Tools


(1) 6--3Watt Led's

(2) Half/Full(doesn't Matters much) Hot Glue Stick

(3)100 Ohm Resistor

(4) A smooth & clean Surface [ i used back side of f2 pcb ]

(5) Wire (of your desired Length)

Tools:- (1) Soldering Iron

(2) Solderwire

(3) General Purpose PCB

(4) Hot Glue Gun

(5) Mini Screw Driver

(6) Small Scissors

Step 2: Soldering First Led

First Take the General Purpose Pcb and Solder 1 Led End on it.

By doing this Leds will not move while making Shape

Step 3: Think of the Shape You Want

Think the shape you want. In my case i am making a Circle Type with 3-3 parallel Led's

[Note:- I am using a 12v Power supply , Therefore I am giving like 4 v to each of led which will trigger there max Brightness.]

Step 4: Soldering the Desired Shape

Solder the Desired Shape, the only reason to make a Circle is to make the next hot glueing work easier.

Step 5: Plucking the Light

Now we will Take our Screwdriver and pluck the light .

[By this i doesn't mean that breaking the joints]

By plucking the light i mean that the cooper traces on which light is solder , that should be detached from pcb. Therefore it could be easily done by bending light up with screwdriver.

Step 6: Adding the Resistor Parallel

This Resistor doesn't Actually Do anything as it is installed in parallel and is just for supporting melted glue [In Step 8].

Step 7: Attaching the Wire

It is Obvious That we will use an insulated Wire . For this. [Be Very Sure that there are no cracks in insulation]

Step 8: Insulating the Full Light

In this Step the only work left has to be done by the hot glue gun.

1) Start by placing a huge dot in middle of any smooth surface [ Wait a little bit and dot should start making a circle]

2) make sure that the hot glue circle made is atleast 2mm thick and exactly of the light size.

3) Now, Put the Light on cooled Circle ( which would become the base of light)

4) Again , put a large sum of Hot Glue on Top of it and make sure all electrical path ways are covered.

5) immediately put it into a freezer and let it cool down.

Step 9: Again Plucking the Light

Again pluck the light by our mighty :p Screwdriver from one end.

No problem if it is not a perfect circle as we will cut the edges to make it a perfect circle.

Step 10: Make It a Perfect Circle

Now take your Scissors and cut the edges to make it a perfect circle.

Step 11: Test It!

Now take an 12v Led Strip Adapter and hook it with the light! And dip it in the water

And Here we Go ! We have made our own underwater light ! Only for 2-3 dollars!

If you liked this instructable then please Vote For me in Budget Contest!



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    14 Discussions

    I can confirm this. While plants cutting, i accidentally cut a probe wire of my digital temperature gauge before many years and sealed the patched part, which is under water, with hot glue. Works well since then.

    Btw, could you post a picture from this nice light in action? I wonder how it looks like and in which position you use it in the tank?


    4 years ago

    I did some more research on hot glue. It is safe for your fish, but it hardens too much. Hot and cold cycles will lead to cracking. 100% silicone stays flexible but might not tolerate the heat of your light. Super Glue Gel is what most pros use for gluing aquarium decorations. Not sure if that would work for your light.

    1 reply
    Mr AbAk

    4 years ago

    Cool Ible....


    4 years ago on Introduction

    If you put 6 3W LEDs inside the hot melt without a way to dissipate the heat, the LEDs will quickly get very hot and soften the hot melt and/or burn and die. You need some way for heat to get out. Also: it is not quite right to simply hook a voltage source to the LEDs, normally a current limiting part is also needed.

    4 replies

    Have you read all the steps first??

    I should simply say that NO

    Because I first tested 1 Led with my 60watt Hot Glue Gun and it went safe!

    And for second. Have you read Step 3?? It is already said that it runs on 12v !

    And on the last step too there is a 12v power led hooked up!

    Please just read all the steps before Commenting.


    Unfortunately your comments indicates you have not really read what I have written. You can't push 3W of power through an LED unless you provide some way for the heat to dissipate. That you had a 60W glue gun is completely irrelevant. Second, you need CURRENT regulation, not VOLTAGE regulation for LEDs to operate safely. Please read the comments before replying.


    4 years ago on Introduction

    I like it!
    However, I would recommend using clear silicone instead of hot glue.
    EVA is a common material used in hot glue, there are two characteristics that make EVA less than ideal for encapsulation of a submersible electrical object, the first is that EVA is somewhat porous (technically it has a high diffusivity for water) and secondly the EVA will eventually release acetic acid which can corrode the electrical systems. Even for all that, almost every solar panel is manufactured with EVA as the binding agent. Although, it's normally sandwiched between PVA and Glass. My info comes from some science journal articles I was reading last year for my senior research project.
    but again, I do like your project, I even voted for you ;)

    1 reply