DIY LEDs - The write-up

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stugray said:
(Just drilled & tapped ~150 8-32 holes in the last day, so, I have an idea ;-)

Stu
Click to expand...

Hi Stu,

I thought you mentioned in an earlier post that you built some type of jig for tapping. Can you elaborate? I've not had much luck with tapping for small screws - I keep on breaking #4 taps and have reluctantly returned to using epoxy.

Regards,

Hesham
 
JoshuaG said:
Here is my latest build, I would love to hear some opinions on how you guys would cool it. It's going to be in an enclosed fixture, my plan so far was to do something similar to the ATI PM fan setup. 3 fans pulling in air from the top left and exiting out the end cap on the right side.

23b1d1df.jpg


71fddcf0.jpg
Click to expand...

If you want to get extravagant try sealing the channels and using them as cooling ducts. Seal the top of each LED channel and one end. Mount a fan over the other end of the channel blowing in. Then drill holes at the end of the channel you sealed so the air blows out against the T5 tube. The warm air will still cool the T5 fine and you will also keep your LED's cool

Nice build.
 
"I thought you mentioned in an earlier post that you built some type of jig for tapping. Can you elaborate?"

All I did was take a piece of the 1"X1" Aluminum channel that I make my heatsinks out of & drilled a hole through the two sides the same diameter as the Tap I am using ( with a drill press to get it straight ).

Then I hold that tightly against the Al, over the hole, insert tap & turn.

It holds the tap straight while I get it started.

Then I come back later & chase the holes again with the tap to get them cleaned and as deep as I want.

Stu
 
The Grim Reefer said:
If you want to get extravagant try sealing the channels and using them as cooling ducts. Seal the top of each LED channel and one end. Mount a fan over the other end of the channel blowing in. Then drill holes at the end of the channel you sealed so the air blows out against the T5 tube. The warm air will still cool the T5 fine and you will also keep your LED's cool

Nice build.
Click to expand...

I could change to using square tubing instead of the channel, and use a fan for each one like this. This one might not have enough "upmh" though.

http://www.mpja.com/prodinfo.asp?number=16720+FN

Hmmm, that is pretty interesting. I might give it a try, thanks:)
 
King Rich; Your plan is sound. Go with U-channel as then you can re-orient and combine your initial build with additional units in the future.

JoshuaG, Grim. Boxing those or using tubing is not a good idea. Your temps will go way up. Square tubing is a disaster for cooling. Trying to run air down those tubes is hard to do as the restriction is large and no fans correctly mate to the tubes. You then need fans with higher pressure output not available with 'computer' fans. If the tube was 4 inches square or something then maybe..

A great deal of the heat rejection from heatsinks is thru radiation. When you go to a tube you remove almost all radiation cooling from one entire side of the heatsink, (the now inside).


Anyway, you should be trying to cool all that heat rejecting stuff, even the T5s.

The very best would be a full enclosure. All six sides. The enclosure longer than fixture by about six inches on either end. Fans mounted all along one end blowing out. Holes galore on the other end to draw from.

Next best would the holes and fans turned 90 degrees pointing up. This allows the enclosure to be just the length of the fixtures with only a little loss of cooling at the very ends.
 
kcress said:
JoshuaG, Grim. Boxing those or using tubing is not a good idea. Your temps will go way up. Square tubing is a disaster for cooling. Trying to run air down those tubes is hard to do as the restriction is large and no fans correctly mate to the tubes. You then need fans with higher pressure output not available with 'computer' fans. If the tube was 4 inches square or something then maybe..

A great deal of the heat rejection from heatsinks is thru radiation. When you go to a tube you remove almost all radiation cooling from one entire side of the heatsink, (the now inside).

Anyway, you should be trying to cool all that heat rejecting stuff, even the T5s.

The very best would be a full enclosure. All six sides. The enclosure longer than fixture by about six inches on either end. Fans mounted all along one end blowing out. Holes galore on the other end to draw from.

Next best would the holes and fans turned 90 degrees pointing up. This allows the enclosure to be just the length of the fixtures with only a little loss of cooling at the very ends.
Click to expand...

Thanks. My original plan was to copy the ATI PM. 3 fans on the top sucking in cool air and exiting it out one side.

1124992015.jpg


ATI2003.jpg
 
JoshuaG said:
Here is my latest build, I would love to hear some opinions on how you guys would cool it. It's going to be in an enclosed fixture, my plan so far was to do something similar to the ATI PM fan setup. 3 fans pulling in air from the top left and exiting out the end cap on the right side.

23b1d1df.jpg


71fddcf0.jpg
Click to expand...

What kind of bulbs are you going to run and what are the color of the LEDs you are planning on using as well? Looks like a wicked build for sure and I wonder what kind of PAR you are going to get and how close/far you will have to hang it...
 
Arrrrrgggghhhhh - stupid is as stupid does.

Arrrrrgggghhhhh - stupid is as stupid does.

Stupid #1 - I mistakenly got Arctic Silver thermal grease rather than thermal apoxy. Yes, I know the difference! ... I didn't realize until the next day when it wasn't drying :)

OK, I might as well go with screwing them all down so off to HomeDepot for a drill/tap set for the 8-32 screws and mail-order 200 5/16 8-32 screws (really bolts I guess) and washers.

Stupid #2 - Seems like the tap is tapered and you need to tap pretty far in to get the tap to its thickest which is the proper threading I assume. I break the fri#*&#$^ tap on the VERY FIRST TAP!!! Right down nearly flush with the heat-sink surface. I am manually using the tap in a hand bit. I can't even easy-out the bit. Zero down, 126 more to go.

God help me!

Anyone else having trouble breaking taps?
 
HeneryH said:
Stupid #1 - I mistakenly got Arctic Silver thermal grease rather than thermal apoxy. Yes, I know the difference! ... I didn't realize until the next day when it wasn't drying :)

OK, I might as well go with screwing them all down so off to HomeDepot for a drill/tap set for the 8-32 screws and mail-order 200 5/16 8-32 screws (really bolts I guess) and washers.

Stupid #2 - Seems like the tap is tapered and you need to tap pretty far in to get the tap to its thickest which is the proper threading I assume. I break the fri#*&#$^ tap on the VERY FIRST TAP!!! Right down nearly flush with the heat-sink surface. I am manually using the tap in a hand bit. I can't even easy-out the bit. Zero down, 126 more to go.

God help me!

Anyone else having trouble breaking taps?
Click to expand...

8-32, that's a big hole, I use 6-32, they fit in the slots on the stars better.
As for the washers, plastic/nylon? I hope, helps from possibly grounding out a LED.

As for the tap, did you put a little oil on the tap, or down the hole before you started? If not, binding and breaking is going to happen.

I hope you're build starts getting better for you.
 
Needed some heatsink to cool my driver and while cutting it I got an idea.
So I think I finally figured how to mount these LEDs so I will be happy.
picture.php

You can't see it but there is a screw on the back side to lock in the desired angle.
Now I need to figure out a good way to make the bar tipable. Got an idea on how to implement that; just not sure if it is in my skill level.
 
Thanks Craig. I will try oil next time. The build has gone well so far. All of the LEDs are wired and tested; I just need to permanently mount them. I used 10mm square MCPCBs so the 8-32 screws with fiber washers should work well.
rcgates said:
8-32, that's a big hole, I use 6-32, they fit in the slots on the stars better.
As for the washers, plastic/nylon? I hope, helps from possibly grounding out a LED.

As for the tap, did you put a little oil on the tap, or down the hole before you started? If not, binding and breaking is going to happen.

I hope you're build starts getting better for you.
Click to expand...
 
HeneryH said:
Thanks Craig. I will try oil next time. The build has gone well so far. All of the LEDs are wired and tested; I just need to permanently mount them. I used 10mm square MCPCBs so the 8-32 screws with fiber washers should work well.
Click to expand...

One other item to note about tapping holes, if you haven't done it before.

Not only do you need oil, but do no try to do the full tap in one pass.

What you do is get about 3/4 to one full turn on the tap into the hole, back the tap up a thread or so and then back into the hole, cutting only about another 3/4 to full turn.

This helps pull the shavings out so they don't bind the tap in the hole and possibly break the tap.

Test your tapping on a test piece of aluminum, get a sheet of 1/8 or so and practice before you go for the heat sink.
 
HeneryH; Since #8s are massive overkill I would suggest you make the holes larger than normal. This would GREATLY ease the tapping. Maybe not to the point of having a giddy stupid grin on your face, but it will be much better going. Like a number 28 drill instead of the 29.
 
Just an option for drilling and tapping. I tried it unsuccessfully, snapping off several taps in the heatsink and which are now permanently part of it. Afterwards, i decided to drill straight through, used a 3/4 inch screw and put a nut on the other side.
 
I have drilled & tapped over 350 8-32 holes in the 1/8" Al channel & the heatsink USA stuff.

I have broken ONE tap, and that is because I bolted the channels together first and hit one of my bolts while tapping.

Oh, and my 12 year old son did about 50 of them.

You guys must be doing something wrong.

After EVERY hole, I clean off the tap, inspect for any Al stuck in the teeth & re-oil.

I did 48 holes in the 2" fin heatsinkusa stuff drilled & tapped ( all the way through ) in less than 2 hours.

Stu
 
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