Thursday, June 6, 2013

Gelling a LED Lamp

So I'm a fan of these inexpensive CREE LED bulbs, at amazon.com. At 9 watts. they are as bright as a 35 watt halogen, last essentially forever, and have a warm white color with acceptable CRI (though LEDs will likely never be quite as good as incandescents in that respect).

They are bright enough and wide-spectrum enough that you can add color gels, and it's pretty easy. The faceplate is held on with only 3 small screws:

Taking apart the LED bulb

Take them out, and the faceplace comes off, along with three lenses which sit on top of the three LEDs. Don't lose the tiny screws! You can see the three 3-watt LEDs attached to the heatsink.

LED bulb parts

You can use any gel you want to change the color. I had these in my collection, I think they are Roscolux brand but I'm not sure. The combination of pink and orange gave a color I liked.

Colored gels

So I cut out a triangle from both gels big enough to cover all three LEDs and put them on top of the lenses. Carefully putting the body of the lamp on top sandwiches the gels between the LEDs and the lenses. Even though the lenses are concave to fit over the LED dome lenses, there's room enough to scrunch up the gels.

Gels cut to fit inside lenses

Carefully screw the faceplate back on. You will need some pressure to compress the new gels. Et voila! A color LED lamp, with a gentle tint:

Gelled bulb reassembled

It's too bright to photograph directly, but I put it in a fixture next to an unmodified LED lamp (to the left) and halogen lamps (pointing down) so you can get a little bit of the color effect:

Gelled bulb has warmer color
Since the LEDs are sitting on a metal heatsink, they don't get too hot even with the gels, I've had one running continuously for two weeks with no problems.

If you are keeping track, this is my Lamp of the Month for May (oops!)

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