How I built a 12V LED fixture for the shed. The new shed (replacing the one Hurricane Irene crushed) needed a ceiling light. And since I like with these, and I had some around, figured I'd build ceiling fixture that spanned two of the ceiling joists.
Stats: 2000 lumen, ~ 22W , 6 K color temp , 96 LEDs used
LEDS: SMD 5050 LED strips. These are 60 per meter, cuttable every 3
Although I had used PVC has an LED holder in the past, 96 of these were generating way too much heat. See picture below, noticed the discoloration. That idea , discarded.
Next thought process, is OK make it on aluminum, in this case .090" sheet that I had lying around. Problem, you can't just lay these strips down on aluminum. There are exposed contacts every 3 LED's, just placing it on sheet would produce quite a bit of magic smoke and sparkage when turned on. I still wanted to use the aluminum though, good heat sink. So what I did is drill holes anywhere where there would be a contact. Layed the strips down, then flipped the plate over and filled the holes with epoxy resin. See next pics
This is the backside, with the holes.
The full fixture
Backside of fixture
In the Shed
I would do this again, entire unit is a heatsink and casts a lot of light