Stuck with Non Electrically Isolated slug LEDs, Kindly HELP!

[bhvm]

Dear all,I have about 45 pieces of Seoul P4 LEDs that have their Slugs as Anode! They've been sitting around for a while because i could'nt figure out how to wire them. I usually use Aluminium bars for heatsinks, but putting these leds cause an short !
suggest me how can i put these to good use?I was planning to make an 40 LED Light for my hall.BTW, I am going through these threads but AA is not available here. http://www.candlepowerforums.com/vb...ad.php?297236-Non-electrically-isolated-slugs

 

[RoGuE_StreaK]

What about the "heatsink plaster" sold on dealextreme for $2.15? Reviews indicate it is (electrically) non-conductive.
SKU 37514 (not sure if it's OK to link when suggesting a product as a solution?)

 

[uk_caver]

I have in the past glued P4 emitters to Al plates with thermal epoxy and hardly ever got electrical contact, though that was in a case where contact wouldn't have been a problem since I was using single emitters

I've also used a very thin coat of clear nail polish as an insulator on P4 bases before sticking them down with Arctic Alumina or JB Weld without any obvious thermal problems running at up to ~500mA.
Gives a fairly thin layer if used fresh rather than letting it dry out and thicken on the brush.

Currently I'm using LEDs where there's no issue with unisolated slugs, but when I stick driver boards base-down onto metal panels, I use a sandwich of a piece of lightweight cigarette paper between JB Weld either side to ensure there's no contact however hard I press things together.
Thin paper can get down to 20 microns thick, and as long as the epoxy wets it, it seems to work fine.
Normally I put a thin layer of epoxy on the baseplate, press the paper into it and smooth it down flat, and then push the epoxied driver down onto it.

 

[WeLight]

Most p4 MCPCB stars have no issue with slug base

 

[bshanahan14rulz]

You could buy a sheet of something like silpads or mica insulators, maybe the thermal properties aren't too bad for use with LEDs?

 

[PapaLumen]

If you can anodise the aluminium it will insulate.

 

[mds82]

Ya i was just going to mention, buy a piece of anodized aluminum. McMaster.com has a lot of it in stock for Very reasonable prices as well . That might be the easiest thing for you to do.

 

[mahoney]

I've used heat sink tape or a tiny piece of mica with artic aluminia heat sink compound on both sides to isolate Seoul LEDs with good results

 

[Norm]

Positive LED slug epoxy trick

Norm

 

[bhvm]

What about the "heatsink plaster" sold on dealextreme for $2.15? Reviews indicate it is (electrically) non-conductive.SKU 37514 (not sure if it's OK to link when suggesting a product as a solution?)

Thanks dude!Suggesting product helps, however, for $2.15.. thats more money than LED emmiter itself! Anyways I'm in India where this stuff is not available or not shipped to. I found an solution anyways, please read on to know more.

 

[bhvm]

I have in the past glued P4 emitters to Al plates with thermal epoxy and hardly ever got electrical contact, though that was in a case where contact wouldn't have been a problem since I was using single emittersI've also used a very thin coat of clear nail polish as an insulator on P4 bases before sticking them down with Arctic Alumina or JB Weld without any obvious thermal problems running at up to ~500mA.Gives a fairly thin layer if used fresh rather than letting it dry out and thicken on the brush.Currently I'm using LEDs where there's no issue with unisolated slugs, but when I stick driver boards base-down onto metal panels, I use a sandwich of a piece of lightweight cigarette paper between JB Weld either side to ensure there's no contact however hard I press things together.Thin paper can get down to 20 microns thick, and as long as the epoxy wets it, it seems to work fine.Normally I put a thin layer of epoxy on the baseplate, press the paper into it and smooth it down flat, and then push the epoxied driver down onto it.

Thats Terrific Mr caver.I used the nail polish trick yesterday and have been testing 4 LEDs on a single piece metal. No problems yet. Your Cigar paper method looks interesting as well, will try it out someday.

 

[bhvm]

Most p4 MCPCB stars have no issue with slug base

Thats right, But what i have now are bare emmiters. The nail polish method seems working for me.Now i am keen on getting future purchases with MCPCB stars only. Bare emmiters are also too hard to work with!

 

[bhvm]

You could buy a sheet of something like silpads or mica insulators, maybe the thermal properties aren't too bad for use with LEDs?

yep, My wife suggested the same. However i feel we are putting two extra layers of glue this way. First Glue Mica to heatsink, then Glue emmiters on it. Now I am using a coat of nail polish. One coat and it seems that's all it will ever need.

 

[bhvm]

PapaLumen and MDS, will try that. However my plans are to build the lights on an existing structure at my house. That's an interesting project, I'll post pics and instructables soon.

 

[bhvm]

Positive LED slug epoxy trick

Norm

Mentioned that in my first post.
However, i don;t know what went wrong with those GIF things... they're messy!. Can someone guide?

 

[RoGuE_StreaK]

Thanks dude!Suggesting product helps, however, for $2.15.. thats more money than LED emmiter itself!

More than 45x emitters? That tube will do a looooot of emitters, so spread the cost over how many it will do.
Not that it's of any help if the don't ship to India.

RE: Smileys, just click on the smiley you want and it should auto-insert? No need for trying to insert the code?

 

[bhvm]

:mecry:
The nail Polish Aint working. After a few hours of use, Perhaps the heat or Ionization darkens the coat and eventually kills it off, Shorting the LED slugs to base :(

I finally used masking tape and PVC glue to fix the LEDs. Sure, the thermal path will suffer, but its better to have Hotter, Working LEDs than Burnt/ Short LEDs.