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My Home Built CFL Fixture (pics)

Posted by somegeek 8b Wash (My Page) on
Thu, Apr 30, 09 at 14:18

After doing a bunch of research and not seeing stellar results with my 2' T12 2400 lumen 40W setup, I decided to build a CFL lamp. My growing space is cramped on a bookshelf so I have ~26" of width to deal with. Otherwise I would have just gone with a 4' 4 x T8 lamp setup.

My materials list:
(6) sockets - $1.50 each at Home Depot
(3) 2-pack - 26W 6500K CFLs for ~$21.00 at WalMart
Piece of aluminum duct from True Value - $3.50
Some wire from an old extension cable to wire stuff up
Small piece of pegboard - 1/4" wood material minimum to support bolts
Old PC power cable with end cut-off
Electrical Tape
Solder and solder iron
Some nuts, bolts, washers from True Value
Aluminum tape
Coroplast shroud (built previously)

Pics show the general assembly.

Got started by cutting the board to size which the reflector and sockets would mount to.

Put a towel in my shroud so the bulbs wouldn't roll around while I figured out what kind of layout I wanted.

Drilled the board and reflector and mounted using the screws.

Drilled holes for the AC wiring.

Bent the socket tabs and drilled the holes in the tabs so the bolts would fit. Pre-bent pic of socket...

Taped the sockets for some extra reflectivity.

Mounted the sockets with two nuts(jammed) and wired them in(black wire(hot) to center pin and white to shell(neutral)).

Put hot glue over the terminations on the back of the sockets to prevent any shock risk.

Installed wire loops on the board for the hanging chains through the shroud.

Pressed the board/reflector assembly down to the bottom of the shroud (reflector is a bit springy) and taped in place at the edge of the reflector using 2" foil tape(very solid adhesive on this stuff).

Screwed in lamps - voila.

I put up some mylar ($3 emergency blanket from the camping section at Walmart) and the amount of light reflected back in
is insane.

9600 rated lumens at 156watts. I'd read a lot of places that the CFLs run cool but I imagine that's only when they're single. With these six running, there's a little bit of heat in the reflector housing so I installed two 80mm PC fans(one pushing, one pulling). You can run PC fans using a wall wart with enough power.

Will pick up a 6-pack of 2700K bulbs ($13.88 at WalMart) for when I try to get stuff to flower.

I run this about 3-5" above my seedlings. Any lower and the radiant heat starts to dry foliage out. You want to get as close as you can without damaging your seedlings/plants. Light intensity(lumen count) drops significantly as you are further from your subject.

A quick light solution would be to pick up a Clamp Light and a large CFL. You could go one step further and install a Y-socket adapter in one of the larger clamp lights and run two CFLs there. Most hardware or big box(Home Depot) stores have this stuff. Certainly makes a difference. :)

Follow-Up Postings:

RE: My Home Built CFL Fixture (pics)

A very professional look to it. Clever use of ducting there. Out of curiosity, why did you decide to use CFLs rather than tubes?

RE: My Home Built CFL Fixture (pics)

Thanks for the kind words. :)

Fluorescent tubes have a little bit of a dead spot at their ends. Approximately 6" on each end. With a 2' tube I had about 1' of good lighting and the tubes were 1200 lumen each for a total of 2400. Without swapping the ballast, I was stuck at that given the 20W max per bulb position. With a 4' tube, you have 3' of good light but my space is quite confined so I went the CFL route.

Tried to save a few $ too - this was the best bang for the buck setup for me.

RE: My Home Built CFL Fixture (pics)

Wow, nice! I see you took my advice from the privious thread, and then some. This should get your seedlings going for sure! Dampening off should be a thing of the past with this setup.

Just remember to put you hand under the lights to until it feels just warm. That's the distance that the top of the plants should be to the lights. You'll find that you can put them a little closer to the lights if you have a fan blowing on the plants.

Again, nice work, and good growing!

Here is a link that might be useful: somegeek's old setup

RE: My Home Built CFL Fixture (pics)

That's a damn fine fixture. Every bit as good as one they'd charge you $80 for without all the needless expense and the added benefit of pride in workmanship.

You can't beat that with a stick. I'm tempted to copy this design.

RE: My Home Built CFL Fixture (pics)

Man! that is a power house. Good workmanship too.
I have a simple one I made with the same Aluminum duct, but a two bulb socket that points opposite each other. Two 40 watt 6400K bulbs. Realy makes those seedlings get up and grow.
My thoughts on CFLs is that they are great with reflectors but too hot or too far away when used without a reflector. I burned some branches of my container tomatoes with bare bulbs that way.

RE: My Home Built CFL Fixture (pics)

Thanks guys. :)

Here is the result so far with some new seedlings...

Night and day compared to my previous setup. Looking forward to trying peppers and basil this coming winter.

I've had to rearrange the seedlings by height so I can evenly keep the lamp as close to them as possible.

RE: My Home Built CFL Fixture (pics)

I'm sure I don't have to tell you, but you can fight the height problems by pruning them back. In fact, even if I have plenty of room I cut back basil in particular as frequently as I can just to keep it in check. Also, it grows a lot bushier if you do.

RE: My Home Built CFL Fixture (pics)

Besides harvesting, I cut my basil back in the garden to get it to get the shoots to multiply... curious though - how soon can you start cutting back to force multiple shoots? I've been eye balling my starters and wondering this. I read three sets of leaves.

RE: My Home Built CFL Fixture (pics)

I'm in the early stages (wandering around HD, pricing things) of my first DIY grow light for my peppers. I could go either way, CFL or T8s, it's the shroud I'm curious about. I was thinking of making it purely out of sheet metal / ducting but I like the coroplast+peg board idea as it seems easier / lighter.

I pretty much failed arts and crafts, any tips on creation of the shroud?

Thanks for the inspiration.

RE: My Home Built CFL Fixture (pics)

Measure three times and cut once. :-) As long as you have a metal reflector, you should be good with whatever direction you go to build yours.


RE: My Home Built CFL Fixture (pics)

Metal reflector... check. I'm even leaning towards the easier / cheaper / less professional draping of reflective material from the fixture or using white foam-core around the entire seed table, creating one big "light box".

We'll see how it turns out...

RE: My Home Built CFL Fixture (pics)

  • Posted by t-bird Chicago 5/6 (My Page) on
    Sat, Mar 31, 12 at 10:18

This looks great! Kudos to you! You are quite handy. Me, not so stuff is basic and looks weird....luckily - the plants are taking over so their verdure is hiding the ugly...

RE: My Home Built CFL Fixture (pics)

I made one similar, I guess you saw my video. That was 4 years ago and people are still using the vents. I'd say the vent industry owes me, lol. Anyway I have more info now that it's 4 years later.

Here is a link that might be useful: Build CFL Grow Light Info Link

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