High power LED bike head light with integrated heat sink

Step 7 Install the Lens and Electronics

Once the LED epoxy has cured, epoxy the holes you drilled in the back of the copper cap with JB Weld or similar. Make sure they are well sealed. With the same epoxy, dab some in the cutouts on the front side LED star to hold the legs of the lens. Don't put in too much or it may squeeze out and get on the LEDs or lens. With the epoxy in place, insert the lens. Using masking tape or similar hold the lens tight and flat to the back of the LED housing while the epoxy cures.

Once the lens and wire sealing epoxy is cured we can install the electronics. Coil the extra wire as needed and check your fit. Using silicone RTV (room temperature vulcanizing) sealant or caulk or even epoxy fill the gaps around the Buck Puck in the compartment so that the electronics are both held in place and the cavity made water tight.

One thing, the RTV produces acetic acid during cure (the distinctive smell of curing silicone caulk) which etches copper and can impact the adhesion of the sealant to the copper. Epoxy is a better but messier choice. I went with RTV since I didn't think I was going to use this underwater and because the epoxy would be a permanent, irreversible step.

Similarly, caulk or seal or epoxy around the top edge of the lens to seal the LED side from the elements. I used a silicone RTV again, and if it fails will go to a liquid nails type adhesive/sealant. Be careful to keep whatever you use off of the lens face.