DIY LEDs - The write-up

[kcress]

DFason; That is f a b u l o u s!! Spectacular sheet metal. You own a sheetmetal fab shop right?

One concern.. I see the fan hole in the top. I see the vent holes on the sides. Due to the vulgarities of air molecules those vent holes are only going to allow 1/20th the air thru that can go out that top hole. Tell me air can go in all the light holes?

 

[akindbro4u]

is everyone still getting there heatsinks from heatsinkusa, or is there a cheaper place you have found?

 

[Reef_Matrix29]

That's where I got mines from and I got two 8 x 11 inch heat sinks for under $50 shipped.

 

[der_wille_zur_macht]

I am thinking of trying self tapping screws for mounting LEDs. Anyone have any experience with them? Also what size screws work best?

Thanks

Self tapping are fine, I've used them on many builds. I'd have to look the size up on the packaging, but IIRC they're #6 screws.

is everyone still getting there heatsinks from heatsinkusa, or is there a cheaper place you have found?

Many people are now using extruded channel or L, which can be much cheaper depending on the size of your build.

 

[akindbro4u]

at 48x20 it will run me about 250 for heatsinks. Don't think I could get channel, or l brackets thick enough with all attachment hardware for under that. Just checking to see if any heatsinks places were cheaper. Thought it was fairly reasonable myself.

 

[TheFishMan65]

Depending on what current you are planning on running you may not need them thick. I am still waiting for my LEDs, when I get them I am going to measure the temperature ate different currents. I am hoping to get to 500 with only channels.

 

[akindbro4u]

I would be interested to see how well heat transfer is on just channel.

 

[Reef_Matrix29]

akindbro4u, are you looking for one "solid" heat sink or dual half-sized ones...perhaps even 4 quarter length modules? This may make it easier during construction and purchasing, just a thought.

 

[perikaruppan]

thinking of using a small 2.5" X 4 feet long heat sink for each row of LEDs.. i think there will be 20 nos per heat sink..

will this heatsink be alirght?

planning 5 such heat sinks... with 3 fans on top of them all.

to run all the leds at 700ma.

 

[akindbro4u]

I was still deciding on how I wanted to have them cut. I was leaning towards two 48x8.5, but I was also thinking of doing six 16x7.28.

 

[The Grim Reefer]

If you are looking for aluminum bar stock check Lowes. They have flat, angled and channel but the channel isn't that thick. I thought about buying 1 or 1 1/2" bar then riveting the 3/4" channel to the top. About 30 bucks to get 8 feet of both.

 

[widmer]

For my setup, I was originally going to go with U-channel aluminum from Lowes. But after I had purchased enough of the U-channel so that the LEDs could be adequately spaced for proper heat dissipation, it ended up being more expensive than the appropriate amount of heat sink material from heatsinkusa.com.

FWIW I highly recommend heatsinkusa, you can buy any given length and have him cut it into one-inch wide strips for no extra fee, as long as you are OK to relinquish 0.25" per cut due to his enormous saw which he described over the phone to me (ie purchase 5" of material if you want to end up with 4 one-inch strips). It's key to remember that every time you have an interface of two pieces (ie to make a pseudo-finned heatsink from one U-channel on top of another), there is a loss of effective heat transfer at the interface.

 

[kcress]

thinking of using a small 2.5" X 4 feet long heat sink for each row of LEDs.. i think there will be 20 nos per heat sink..

will this heatsink be alirght?

planning 5 such heat sinks... with 3 fans on top of them all.

to run all the leds at 700ma.

If the air moves enough with your fan then that will work.

 

[The Grim Reefer]

For my setup, I was originally going to go with U-channel aluminum from Lowes. But after I had purchased enough of the U-channel so that the LEDs could be adequately spaced for proper heat dissipation, it ended up being more expensive than the appropriate amount of heat sink material from heatsinkusa.com.

FWIW I highly recommend heatsinkusa, you can buy any given length and have him cut it into one-inch wide strips for no extra fee, as long as you are OK to relinquish 0.25" per cut due to his enormous saw which he described over the phone to me (ie purchase 5" of material if you want to end up with 4 one-inch strips). It's key to remember that every time you have an interface of two pieces (ie to make a pseudo-finned heatsink from one U-channel on top of another), there is a loss of effective heat transfer at the interface.

Yeah, Might just go with angle aluminum. I am looking at lighting a 2x4 foot space, thats a lot of heat sink. I am going to space the LEDs out at 2.5 or 3" so I am hoping I wont need a lot of cooling. I dunno, still kicking around ideas.

 

[widmer]

(in reference to perikaruppan's plan)

Based on my experience with my LED sump light, that heat sink will be perfectly fine without any fan whatsoever if the LEDs are placed 2.4 inches a part from each other as described (20 LEDs per 48 inches), even if driven at 1000 mA. That heatsink is almost 3 inches wide...

 

[widmer]

double post why don't I have the privilege of deleting my post..

 

[The Grim Reefer]

double post why don't I have the privilege of deleting my post..

You have to know the secret handshake.

 

[The Grim Reefer]

I tried to delete the previous post, they must have changed the handshake

I think only the mods can delete posts.

 

[der_wille_zur_macht]

at 48x20 it will run me about 250 for heatsinks. Don't think I could get channel, or l brackets thick enough with all attachment hardware for under that. Just checking to see if any heatsinks places were cheaper. Thought it was fairly reasonable myself.

FWIW Heatsinkusa heatsinks for my 360g would approach $600. I'm thinking I can get by with ~$150 of extruded angle. On smaller tanks the difference definitely won't be as great!

 

[HeneryH]

FWIW Heatsinkusa heatsinks for my 360g would approach $600. I'm thinking I can get by with ~$150 of extruded angle. On smaller tanks the difference definitely won't be as great!

What is the length of the 360? I am still considering going with the following type of heat sink since I am leaning towards a hanging fixture.

They run about $67/ft for the 14.5" width. They can be anodized (sp?) for color as well but I'm not sure about the pricing for that.