# DIY Wood Light Fixture



## Consigliere (Jun 11, 2009)

As I posted before, my 20G tank has been running using a 500W halogen spotlight to light it. I'm sure many of you who saw that post had a good laugh. Well, it was justified. I had a huge outbreak of brown hair algae that I'm pretty sure was caused by huge amounts of light and low CO2. I have realized, although I should have known before hand, that this combination won't work. I shut the light down and only ran it for about an hour or so a day until I could get a new light sorted out. I decided to try a DIY fixture using energy efficient spiral lamp bulbs. Total wattage would be about 69W for 20G, or 3.5ish WPG. There will not be reflectors or anything so I figure this is medium light tank and I will be OK with DIY CO2 as long I keep up on them. I think I will supplement the CO2 with some Flourish Excel. The fixture is built from some scrap 2x4 I had around. Outside dimensions are 24 1/8" x 7 1/8". All the frame is secured using 2 1/2" building screws.










Next step was to add some holes for the lights. The back is open so that I can have access to the back and not interfere with the HOB filter and heater currently in the tank. To add the lights, I drilled 2 sizes of holes through the long 2x4. On one side, it will fit the light bulb base, on the other the hole will fit a lamp style light fixture. All of this part was done with a hole saw kit. Here's the fixture with the holes and one light already installed:










The lights are wired in parallel to the a plug with 16-2 lamp wire. Wiring like this is dead simple but if you've never done it before it is worth doing some research and practice since water and electricity are not the greatest mixes. Here's the whole thing wired up and just needing a top:










Last step was just to attach a top to keep most of the light inside the tank. The top is 1/8" melamine coated MDF with the coated side turned in. Also shown are two outside tabs to prevent the fixture from ever falling in the tank. Eventually when I get ambitious I am going to coat the whole thing with marine epoxy to waterproof it but for right now this is going to be OK. Here's the finished product:










I may eventually add a 4th bulb to this fixture but we will see how it goes with these 3. Hopefully it will be enough to at least maintain the current amount of HC in there and have it spread a little bit. All said and done this took about $35 with $14 of that being the epoxy that hasn't been put on yet. I suppose I should have just put the time in to make this earlier instead of trying the spotlight out. Oh well, live and learn. Full details of the build at http://canaquaticgardens.wordpress.com


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## noved (Jul 14, 2009)

nice idea. I think that I might do something like this as well. Are you going to use anything as a reflector.


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## Consigliere (Jun 11, 2009)

Thanks. I may do some reflectors inside depending on how the tank turns out in terms of plant growth etc. If I do reflectors, I am thinking of using some aluminum duct piping and just rolling it flat and cutting it to size. Automatically you may think of tin foil but as a reflector it won't work because of the crinkles.


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## Jonathan (Oct 16, 2009)

Consigliere,

Hats off to an innovative approach to building an energy efficient light fixture with low cost materials. Well done!

I do have a few concerns I would like to share with you since as you say in your post, "Electricity and water don't mix"

Compact flourescent lights or CFL's as they are more commonly called are energy efficient and because of their high surface area to volume ratio, produce a lot of light energy at low electrical consumption rates. The large base of these bulbs contains a ballast which is a device that performs two functions;

1. providing an initial inrush of high voltage (anywhere from 1200 to 9000 VAC) to cause the initial flourescence in the bulb, and

2. A capacitive load to balance the inductive reactance that these devices naturally produce. Under normal operation, the ballast consumes aproximately as much energy as the lamp, and produces heat.

Your fixture has the ballast closely fitted inside a wooden 2 by 4 which insulates the lamp ballast and prevents waste heat from leaving the bulb. There have already been some incidants of CFL's, particularly those imported from the far east overheating at the base and failing under _normal _operation.

My concern is that your design might be a fire risk beacuse you are insulating the CFL base and could cause it to overheat. These lamps are only certified to be used if there is sufficient clearance around the base to allow heat loss through convective air currents.

I recommend that you test the fixture in a non combustible environment (like inside your barbeque) and bring it up to full operating temperature continuously for at least 72 hours to make sure that if won't be a problem in your house.

Also you should include a junction box for your electrical connections rather than taped wire nuts, as required by the _The Canadian Electrical Code_

I hope you don't feel I'm raining on your project, I'm just trying to put safety first...


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## proud2bcanadian (Nov 13, 2006)

Jonathan said:


> Your fixture has the ballast closely fitted inside a wooden 2 by 4 which insulates the lamp ballast and prevents waste heat from leaving the bulb. There have already been some incidants of CFL's, particularly those imported from the far east overheating at the base and failing under _normal _operation.


That was the first thing that I thought of too when i saw this post. It is a great idea, and it looks like it would work. If you want a quick fix, go and get some ceramic light fixtures from Home Depot (a bit bigger than a hockey puck in diameter) and attach them to the underside of the 2x4, then you can screw the bulbs directly into it without having to worry about overheating issues.
Also, remember that whenever you make an electrical connection, make sure that it is not exposed to wood. By that, I mean, put some sort of metal sleeve (conduit) in between the connection and the wood. In a case where the current would arc, it could spark a fire if it was exposed to wood (let's say if there was a power surge/lightning strike).

As with the post above, I don't mean to trash, I just want to make sure that you'll be safe. Years of DIY work and being in the trades right now have/has taught me some things (unfortunately, in some cases).

Regards,
David


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## Zebrapl3co (Mar 29, 2006)

Same here, didn't see this post before, but a very good idea though.
I would've add a mylar reflector to improve on the design.
Heat is a concern, good point. And I agree that the jimmy electrical is pretty dangerous (the stuff you hardwire with the yellow twisting thingy). You will need to box it in.

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## jooony (12 mo ago)

u can buy similar instead doing yourself and pay not much money on Industrial table lamp | Edison light fixture - WoodPresents


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