WOW!!! That was fast!!! The solder melted in about a minute. It got up to about 150C and things got melty. Cool!!!
As a test, I took my little induction stove (actually it’s a ‘toy’ stove, shaped like a duck). Set the pot on there, put an empty star in the middle with a piece of solder on it. Turned it on high and waited a bit. After about 30 seconds and a few snaps and cracks from the pot, I switched to low. Not very long after, the solder melted into the star pads. I think I have a new way to reflow!
I had heard of the skillet method, but the hassle of going to the kitchen instead of the minute or two right there at the iron… now I don’t have an excuse. 
Well, I probably will still go to the iron… it’s always set up and ready to go.
Thanks for the tip! if I have to reflow a bunch of emitters at once, this will be the way I do it.
I only have an electric element kitchen stove. I use a small heavy aluminum frypan. I place the star in the pan with the LED in place and turn the stove on high. As soon as I see the emitter sink down on the star I pluck it out with tweezers.
I have to be quick, as there is no real heat control with an electric element. I was looking at these small portable single burner propane stoves for woks, at the asian grocery accross the street($12). Quite small, hook up a gas bottle, and I would have more controlled heat. I’m jhust leery about having a gas source in an apartment.
I’m still looking for something small and inexpensive to suit my reflow needs.
Glad to help Relic, I meant to say that our glass topped stove is an induction unit but could’nt think of that term “induction”.
lol
I got the stainless plate when my wife and I were trying to can some plum jelly and found the bottom of our big canning pot had a recess in it and the induction surface wouldn’t stay on. The big ol pot was made in the day of circular heating elements that are usually raised, the recess helps keep the pot centered on the burner. Made it really tough to keep that big pot boiling on a smooth glass induction burner! With this 6” circle of SS on the element, that’s no longer a problem and the heat control works as it’s supposed to. I turn mine up to about 6, then off when the flux shows up. When the solder melts seconds after that I move the plate off that burner to the cool one above it and give it a few more seconds to start cooling before removing stars to the aluminum heat sink. That SS plate stays hot for quite a while!
The plate also keeps me out of trouble concerning the wife’s cook pans and solder with lead in it. 
Ouchyfoot can’t you just not turn the burner on Hi? Use Med heat? Or, heat up the pan first, then lay the star in the pan with the solder paste and emitter already on it. As the pan is cooling down, it’ll heat up the star and reflow the emitter without excess building of heat that might scorch your star or worse, fry your emitter.
Hey Dale, induction is a good heat sourse for this. You get good heat control, and there’s no flame or scorching hot element when you’re done.
I posted this on another thread, but since we're talking about it, I'm reposting it here as well.
Okay. I think I've got it. Just so you know, I have to work on my dining table, so everything has to be small and simple. The last time I tried, I couldn't get the star hot enough because the metal in the "Helping Hands" was stealing my heat. Today I bought a small vise grips style c-clamp, and glued some leather to the "clamps". This worked perfectly, almost too good. It was so fast, you can see where the topside of the star scorched brown...it scorched the leather too. Next time a little less heat. Usually, I can see the LED settle down, but I missed it. I used a flux pen on the contacts before I tinned them. This pen has a felt tip, and it paints on flux like a marker pen. The flux is clear, like water, or clear marker ink. When I dabbed on the tinning, it went on so evenly, that the Led sat so flat, there was no noticable settling for me to see. Anyway, scorched or not, I tested the LED and it works fine.
Looks like smores; take two stars and put a mini marshmallow in between… Nice and toasty!
As long as it works, right? You’ll get the temperature right and now you know to look for a very subtle LED settling.
I didn’t think an alligator clip would steal that much heat, I didn’t notice much and I use helping hands.
The leather is a good idea, insulates well and resists burning for a while.
Actually, this was faster than the frying pan on an electric stove, and I don’t have to be in the kitchen, hunched over with my face close to a hot frying pan, let alone risk dropping the whole thing upside down in the pan while I’m trying to snatch it out with tweezers.
Just tried adding 7135 chips to a Nanjg 105c for the first time. Surprisingly easy with no difficulties and all chips appear to work.
I added 3x 380 mah chips to a 2.8 amp driver. So output should be around 4 amps.
Technique I used:
- Bend all 3 pins on the 7135 to be added so they point straight down.
- Super-glue the new 7135 on top of the old 7135.
- Apply flux to all 3 pins and the ground pad for both the lower and upper 7135.
- Using large soldering iron soldered ground tab using the techniques described in this thead (loaded iron up with generous amount of solder, then placed solder blob at bottom 7135’s tab and then dragged iron upwards towards top tab.
- Using a very fine tip low wattage soldering iron, soldered all 3 pins of the new to the pins of the lower 7135. Because I’d bent down the new 7135’s pins, they were actually touching the pins of the lower 7135 even before I soldered, so soldering was very easy and required very little solder. I kept the driver board in a small vise to keep it immobile while I did the soldering.
- Used a small file to file off excess solder from around the driver tabs so the driver would fit in my light’s pill.
To help make it easier to see what I was doing I held an Olight S10 modded with an XML2 neutral on medium power in my mouth while soldering.
Result is pretty nice. I now have a 1xAA sized Sipik 58 with copper heatsink running on the new 4 amp driver and powering a triple Nichia 219. Runs on an AW IMR 14500. At max power this light heats up fast so can’t be run more than a few minutes at a time. Also runtime on a full IMR 14500 should only be around 9 minutes. But for short bursts it gives a wide blast of beautiful Nichia tint light.
I also tried this driver powering a triple XPG2 5,000k neutral. Output was much brighter than with the Nichia, but had a much worse lemon yellow tint. I suspect the XPG2 needs more than 1.3 amps per emitter before it starts outputting a better tint. I think I might buy some cool white XPG2s to try out. Perhaps they will have a whiter tint. Or perhaps I could try a triple with 1-2 coolwhite XPG2s and the rest neutral tint.
What’s the proper way to attach 7350 chips to a bare board. If I had a driver with only five or six chips on it and a couple of spots that are empty.
Firelight2, the XP-G2’s in my EDC+ Triple are a very nice white tint, running all 3 at 2A (1.93A measured at the tail) They probably will change tint driven harder, but the 3 in my drop-in are a perfect white…no tint anywhere.
That’s the easy way. Pre-flux and pre-tin the big PCB pad with a small amount of solder. It should be just enough to cover the pad. Most likely, the pads are already tinned so you can just add a little flux and remelt the pad.
The using tweezers, hold the chip over the pad while applying heat to the edge of the pad and tab with your iron.
Once things melt, the chip will sit in place. Let the solder set
Finish up by soldering the other pins; heat first then touch the point where the iron and the pin meet with solder. It should flow right onto the pin and pad.
Success! Sorta…I got 4 of the chips soldered onto the new driver and everything LOOKS good. But it wouldn’t work. I don’t know if I shorted something or I wasn’t getting a good ground or what. I backed up and redid the pill, cut the recess down so the driver in original form would fit lower and the retaining ring will screw down on it and this one works. I’m getting 2.87A at the tail and have 3 solid reliable modes. I’ll check output and beam tonight.
I’m not experienced at soldering. This was the first time for anything with my new Hakko 888 soldering station. I thought it went pretty good, save for the part where it didn’t work.
Congrats! However, did you add 4 chips to an 8 chip board for 12 total? That should be 4.2A (for 350mA chips). Or is there error in your tailcap measurement (although that's an awful lot)?
-Garry
I did add 4 to 8, but that board didn’t work and the stacked chips were going to cause issues with the retaining ring. I tried soldering it in…used the solder as a threaded ring to hold the board down and it was pretty snug, but it wouldn’t work.
So a stock board is running my light with the original 8 chips. I might see if I can add 2 to the bottom of the board but first want to see how it’s performing here. The supposed 5A driver I had in it was only pulling 2.38A so 2.87A is a marked improvement.
By the way, the chips are binned at 380.
Did you test it by touching the pos and neg with leads from a battery, or with the entire assembled flashlight with a battery in it?
I was wishful and put the light back together. Click, nada.
I’ve now recessed the ledge that the driver sits on in the HD2010 pill and now the retainer ring sets on top of the chips on the spring side of the board. Can’t add chips there. I think I can add 2 chips on the inside, gonna check into that.
For now, success with the new driver! Nice lo, great Hi, no whiny mosquito sounds….none, zilch, silencio! Happiness!
The two military trailers in the beamshot below are pretty dang far back! The second one, where the reflector is shining, is 465 yds! The trees behind the trailers are 550 yds from the hayloft I was in. Not too shabby! The camera settings mimicked what I could see. Canon G1X zoomed to 112mm 0.6 sec f/5.8 at 1250 ISO.
I think the chips could be in the way. Perhaps a longer spring. I've been trying to stay away from adding chips on the contact side, unless the driver is hooked up to a separate larger board from underneath.
To save myself headaches, I now pre-test any driver I worked on. I have an LED that I had swapped out of another light permanently hooked up to alligator tipped leads. I attach the clips to the drivers leads and then touch the pos. and neg. with wires from a battery holder. If the LED comes on...your good to go.
That way you know if your flashlight doesn't work after installation, its something else, like a poor connection somewhere.
I actually did solder a different spring, inverted, onto the board. My 26650 LiNiMnCo cell is more of a flat top so the longer wider spring was used to ensure contact. Only one I had so I had to remove it and put it on the stock board when I went that route.
I actually have a couple of emitters on copper stars sitting right beside me, could use them to check that driver easily enough. Nice suggestion and nice set-up. Thanks.
I cut a set of wires and tried the modified driver. It works! The chip addition is a success! I’m blind!
The XP-G2 on copper star with thermal paste sticking it to a copper bar is very very bright on Hi, Med and Lo modes also work. I will find a use for this driver or figure out how to put it in the HD2010 somehow. Anyone able to make me a copper pill for the HD2010? Anybody?
Edit: Uh, perhaps I should have used 2 AA cells instead of a fully charged 14500. How long does it take for the purple haze to go away? Prince would know….
Yeah! I’m glad the driver is good. It sure is nice to know before installation, isn’t it.