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Discussion Starter #1
I used a homedepot $10 T8, Had this a couple of years and use it to start my peppers & tomatoes, and it works pretty good for this. Im going to add 12 leds to this in a config to light an 18x18 exo and 2 15g verts, on my rack.

Supplies
48" T8 homedepot
7 XPG 6.5k leds Cutter Electronics/RapidLed
5 XPE royal blue leds Cutter Electronics/RapidLed
MeanWell LPC-35-700 constant current driver RapidLed
heatsink is 1/4" alum diamond plate Junkyard
Thermal Glue from DX
80* Optics RapidLed
DEWALT DW3191 Nail Cutting Saw Blade Amazon
circular saw
alum foil reflective tape
clamps solder drill bit
40 watt iron RatShack
Alcohol 100proof is best

My first step I moved the T8 bulbs down and out 1/4" using a 9/64ths bit, my reasoning here was to better center bulbs for reflective tape. Then I cut aluminum diamond plate 2"x48" I just found out that a circular saw with the right blade and a nice straight edge clamped down works great for this. REMEMBER SAFETY GLASSES HERE, chips were flying everywhere. The blade I used cut through it like plywood. If you know how to cut plywood you can do this, IMPORTANT I set the blade depth just less than a 1/2", you dont want more blade showing than you need.
 

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Discussion Starter #2 (Edited)
On to the leds
Its best to pre tin the tabs, on the leds you will be wiring too, before mounting to heatsink. You dont want to hold the iron on leds to long, it can be damaged this way. It takes me 5 to 6 seconds with a 40watt iron per tab, and about the same amount of time to attach a pretinned wire too a pretinned tab after led is heatsinked.
Too heatsink led, Clean led and heatsink with alcohol thoroughly, apply some thermal goo of your choice and smooth/spread it with razor/card very thin and smooth. It is important to clamp the led to heatsink now. I just made of a jig out of hardwood, with a indent for led and tabs and clamp. I clamp for 6 to 12 hrs to be safe, stuff I use takes abit to dry.
 

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Discussion Starter #3
Mounting and wiring,
I mounted my heatsink to the wiring ballast cover, with 2 #6 nuts an bolts and 1 #6 1/2" bolt fit nicely into existing center mount. Mounted meanwell driver near fluorescent ballast with more #6 hardware, they are about the same size and fit nicely. Then wirered leds in series, ran positive to one end,an negative to other. Pulling 27 watts on meter and at leds 36volts and .700amps thats 25watts good efficiency. Also added some reflective tape, seams to help abit.
 

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Discussion Starter #4
Alright I ran leds thru some tests and some results
watt meter says led driver @27watts running 12leds @2watts

@2hr burnin leds only, measure heatsink at leds with ir therm
room temp 62 degrees
heatsink 1 deg over ambient roomtemp

@2hr all on, leds and 2 t8 32w
heatsink 76deg, 14 deg over ambient
fixture over t8 bulbs 80 deg
top of fixture over ballast 91 deg

I feel that heatsink is very good and would like to try and push
these leds harder @3watts ea. (I dont have a driver yet though)
 
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