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DIY Building Instructions for Underwater Lighting


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Since I never included such info in my restoration thread I thought I'ld go ahead and share for anybody interested.

So, here's the list of materials and the process of building the underwater lights I built for the  flats boat.



 Smooth On  EpoxAcast 690 resin



Perforated Electronics Board

LED Diodes (10mm) High Output


 Tin Coated Marine Grade Wiring (14 gauge)

 Soldering Gun

Tinned Solder


1/2" MDF Particle Board (Home Improvement Store)

Polyurethane Clear Coat (Home Improvement Store)



I couldn't find the old remnants of the epoxy I used but am almost certain I used the EpoxAcast 690 due to it's UV inhabitant properties.

May sure you weigh the compound and follow the instructions to a "T".





Clear coat your MDF board with 1 coat of clear by spraying method.

Let it cure over night and then lightly sand the surface with 220 grit and an orbital sander.

Spray an additional coat on the surface and let if cure out for a few days until it gets hard.


Cut the board accordingly to your desired specifications.


Glue all the mold pieces together.

Predrill the corners and secure with drywall screws.

Seal the interior joints and wipe smooth.

(If memory serves me correctly, I seem to remember I sealed my interior corners with Elmer's glue and wiped the excess out).


Drill a small hole in the center of the mold slightly smaller than the wiring your going to be using.


Apply multiple coats/layers of mold release to the inside of the form.


Set aside for casting.




Cut your electronics board 1" smaller on the height of the desired finished light panel.

And 2"'s shorter.

This will allow you room for drilling and attachment to your hull.

Space and install your LED diode 3/8" apart from each other.

This is the measurement the actual domed part of the LED diode lens should be from each other once finished off.


Install the diodes one at a time and start soldering the diode legs with tinned solder in a "Series".


Once finished make 1 twist with the wires as close to the back of the LED board as possible and use a small zip tie to chinch the wires together and keep them in place.


There's all kinds of Youtube videos on how to properly solder them in a series.


Solder up a few to make sure you have the proper process figured out.


NOTE: This particular set up won't need any resistors because the max voltage pull will not exceed the maximum voltage they can handle, which I believe is 14.4 volts.


Apply power to make sure your creation lights up as it's suppose to.


Run your panel wires through the small hole in the center of your mold.

Suspend the LED board of the bottom of the mold approximately 1/2" and hot glue around the wires going through the mold to seal.


The LED diode bulbs should be facing upward at this point.


Weigh your epoxy resin and slowly pour into the form from the edges.

This will allow any air trapped under the LED panel to escape.

Best to vacuum chamber any air bubbles out of the resin but not mandatory.

Fill the mold with resin until you still have at least 1/4 to 1/3 of the LED lens still showing and above the epoxy surface level.


Let cure, pre-drill and counter sink 1 hole on each end of the fixture.

Pre-drill holes in the hull o.O where your installing them.

Apply Life Seal or 3M 4200 in and around the holes.

Apply liberally, (lots).

Seal around all outer edges and let cure.

 (Make sure all wax and sealers are stripped from the area of install so the adhesive sealant can bond properly)

Connect to powered switch and your finished.

 Good luck and have fun.

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