A few questions...Which LED is which color and how to clean the RGrB Tri Cree?

So, I just made my first attempt at soldering my Tri Cree LED. Man, getting the heat to soak into the pads was really tough. I think I may need a new soldering tip as I couldn't get it to pre-tin and couldn't get the solder to easily flow. Maybe it's my solder? Any suggestions here?

Anyway, I finally managed to get the positives wired up and I am ready to do the negatives. The red LED is obvious, but the other two, not so much. Is there a diagram that shows which LED is which?

Also, I tried my best not to touch the dies while soldering, but I was wondering if there is a safe way to clean them to be extra sure everything is good to go.

Thanks in advance for any and all help.

I use a AA or sometimes just my saber battery, tie the pos together and just tap the negative to each and note which color it is. Just do NOT look directly at the LED obviously.

Cleaning, Qtip with a little rubbing alcohol should be fine if you're just cleaning flux. Contact cleaner works great

If you have "eclipse glasses" you can use those to look at the LED. The LEDs will seem as bright as the sun.

Funny you should ask....Just finished soldering my RGB LED and made the exact two same discoveries. The first being "Uh.....which one is the green??" Mid soldering session. The second was the realization that the copper heat sink is almost too good at its job and doesn't make it easy to get the solder to flow cause it can't get hot enough. Madcow and Shameem make it look so easy in their videos.

Unfortunately there was only one way i figured out to tell which was which and it was to very briefly touch my 3.7v battery positive and negative to the pads on the LED to test it. It worked though and I didn't blow anything up.

The solder issue was a little less cut and dry. Being brand new to soldering and wanting to do it "right" I had recently bought some .08 lead-free solder to indulge my wife who wanted me to be "safe". Couldn't get it to flow into those pads for anything.

Then I switched to the leaded 60/40 solder I bought in Amazon with my soldering iron a month or two ago. It was the highly reviewed solder from Alpha Fry and I assumed lots of reviews meant it was the right stuff. However when I got it I realized it was 1/16 diameter and not made for precision electronics. That being said, it was like magic on those LED pads. One drop of solder plopped into the connection and it was a perfect joint

So either it was the thicker diameter of the fact it was leaded solder, but it did the job perfectly and going forward I won't use anything else on an LED ever again

Two tricks I learned about soldering up led stars:
1) Solder them BEFORE attaching them to your heatsink (I’ve never tired to solder after attaching to the heat sink, but I wonder why people would think that was a good idea...)
2) It is really helpful to have a variable temp soldering station. Low-ish heat for extended time can still damage electronic components (and possibly melt the re-flow solder holding the led to the star, once again, not me but I’ve heard of it). I crank my iron up (higher than when working on wires and sound boards, etc), and it works well (and quick) for pre tinnign the star pads, after I can get away with slightly lower to solder the wires on.

The trick I used to test LED color is just use the diode test function on my multimeter. It will usually light up the LED just enough to see the color and not risk going blind.

Oh man, I wish I'd have read this thread before trying to solder my first RRW tri-cree a couple of weeks ago. I had exactly the same problems with lead free solder and led on the heat sink. Luckily, I saved my rgb led for my next build, which I am expecting it to be much easier than the first.

Quote:

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Originally Posted by bigkevin61

Two tricks I learned about soldering up led stars:
1) Solder them BEFORE attaching them to your heatsink (I’ve never tired to solder after attaching to the heat sink, but I wonder why people would think that was a good idea...)
2) It is really helpful to have a variable temp soldering station. Low-ish heat for extended time can still damage electronic components (and possibly melt the re-flow solder holding the led to the star, once again, not me but I’ve heard of it). I crank my iron up (higher than when working on wires and sound boards, etc), and it works well (and quick) for pre tinnign the star pads, after I can get away with slightly lower to solder the wires on.

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The fact that I noticed the issue even without attaching the LED to the actual physical heat sink, just with the copper base of the LED with my variable temp soldering iron turned most of the way up makes me even more convinced that the issue all along was my lead-free solder. Bigkevin01, do you use leaded or lead-free solder?

Use a multimeter. Most will have a diode setting that will push a small amount of current thought the led, and light it just enough to see the colour.

Raven beat me too it.^

Quote:

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Originally Posted by djmehs

The fact that I noticed the issue even without attaching the LED to the actual physical heat sink, just with the copper base of the LED with my variable temp soldering iron turned most of the way up makes me even more convinced that the issue all along was my lead-free solder. Bigkevin01, do you use leaded or lead-free solder?

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I use this solder:
Attachment 16672

Only when I tin the star pads, do I turn my iron up to 800 f.