So recently I decided to upgrade the lights on my 20L from 3 of those clamp lights using CFL bulbs to LED because there is a shelf over my aquarium and the lights had to be moved out of the way any time I need to do anything with the tank. I decided to get the finnex ray2 since that light gave high light on a 20L and the price was within my reach. I then started reading about some forum members saying that the light is bright but kind of washed out colors in some of the plants. A few members got the finnex monster ray to compensate for this. I was going to do that but since I just bought the ray2, I didn't really want to spend another 100 or so for the monster ray. Then I read hoppy's thread about using the SMD LEDs to make a light and thought I would do something similar. The original plan was to get the RGB SMD lights and just sticking 2 strips on the ray 2. Once I actually got the ray 2 though, I realized that it wouldn't fit. So then I started looking for aluminum heat sinks to use to build a light. Initially I found some aluminum heatsinks that were made specifically for SMD LED lights but the one I found only held 1 strip or 3 strips of lights max and they were kind of pricey. Then I kind of stumbled upon aluminum door thresholds on Home Depot's website and thought that I would be able to make a semi-decent looking light out of the threshold.
Anyway, I bought a 36 inch threshold and cut it down to the size I need. Then hot-glued the strips in place. The threshold comes pre-drilled with a few holes so I cut the threshold in such a way so that the holes look symmetrical on the light and installed 2 eyelets in the light so I can hang the light over the aquarium when I'm doing maintenance on the tank.
I just finished the light this weekend so no idea on the long term durability of the light but the thinking is that the strips are cheap enough and easy to replace if they do go bad. Total cost for all the parts was around $60 I think but I had enough threshold left over that I made another light for my daughters 5 gallon tank.
I was able to cram 6 strips of light on the threshold. 5 strips has 30 LEDs each and 1 strip has only 18 to make room for the controller so there are a total of 168 LEDs. They are all 5050 RGB LEDs. The light compared to the ray2 is much dimmer but I think if I made this with 5630 white LEDs then it could possibly be just as bright as the ray2.
So far the biggest flaw is that the light gets extremely hot if I run it at full power. It gets hot enough that it's uncomfortable to hold for more than a few seconds. Since I built this light for accent colors I'm not too concerned about the heat yet but I will be monitoring it closely and I will disconnect a strip or 2 if necessary.
Her are some pictures in case anyone is interested