Hmm, that makes me think…what if you stripped a wire a little longer than that bridge between the legs, tin it, then hold it to the legs and make that touch to connect the legs. Snip off the remaining wire right above the upper leg. Might be the easiest way yet as you’ve got the wire to hold it in place by with the tinned portion ready to grab the legs as soon as the iron touches. Voila!
Gonna have to try that next time….if I can remember!
Thanks Ouchyfoot! 
I’ve done the wire trick before, works fine.
Were you trying to keep that little secret all to yourself? :quest:
I find it more difficult than just using solder. The wire has to be really thin. I wonder if solder alloy is a factor… 60/40 vs 63/37. I use the former. Maybe I will pick up some of the latter and try it.
I don’t see why the wire would have to be thin. I just soldered 2 together with 20ga silicone covered wire. Like attaching a pillar in front of the legs, lol. Of course, in this application I’m leaving the wire some 3” long and using it for battery contact and emitter contact.
Hey Ouchyfoot, do you attach the top chip before soldering the legs or do you use the ground solder to hold it in place?
I don’t have anything to attach it with first, or the patience to wait for Fujik (if I had some) to dry. So I just hold it in place and solder the wide ground on the back side first then do the other 2.
I just fasten it on top of the bottom chip with a dab of super glue from the dollar store.
On my next attemp, I might pre attach small wires to the legs of the bottom chip, glue down the top chip, bend the wires up, and attach them to the top legs. I’m also finding it to be easier, and neater to link the thermal pads with a bit of narrow copper braid.
Need to get some of that. Handy for a lot of things it would appear, not the least of which is tailspring mods.
Isn’t the internal bond wire encapsulated inside the chip? I mean that inside the black part, is it just a cover, or is it like potted? If it’s potted, then it seems like that internal wire bond should be pretty secure, so I’m kind of surprised that bending the external part of the leg would break or weaken the internal bond. I haven’t worked with 7315s, but I’ve done that (bend legs/pins) many times, especially while prototyping.
I tried bending the legs down. It sounds easy, but its not, unless you are experienced, and have certain dedicated tools you use. I just ended up breaking the legs off, ruining the chip.
I am new to light modding. Added several 7135s to a few drivers. Bending the legs with needle nose pliers has worked fine for me. Def makes soldering easier.
Ouchyfoot, heat em first with your soldering iron if they’re breaking off. Once heated a bit they bend very easy. 
I’m getting peaks on my solder from the iron pulling it up as I take the tip away, what am I doing wrong? Station set at around 300C (350C when soldering a copper star on a copper heat sink)
I’m always worry about heat transfering through the legs destroying the internals of the chip.
I get peaks sometimes too. I think it usually means I’ve got too much solder. When that starts happening, I keep dabbing at it with the iron to remove the excess, and wipe it off the tip. Flux could also help it to flow more evenly.
Flux and a little more heat could help with the peaks. I set mine around 375C.
The bond wire are encapsulated in the package and are bonded to the pin internally. If the act of bending the lead loosens it in the pacage even a little, it could weaken the bond. The risk is probably low. I don’t bother si ce soldering straight leads has always worked for me.
My 2 Convoy C8s and a 10-pack 7135 arrived today from FastTech and I took the plunge of trying to add 2 7135 chips to one of the C8’s drivers.
I destroyed one chip (broke pin 1) but I managed to attach 2 chips to the driver (though it took very long to connect the pins since my soldering skills are very limited). The problem is that when I reassembled the flashlight, it won’t turn on.
I took the pill out again and tried connecting it to the positive (positive terminal of the 18650) and negative (body) of the flashlight and was further confused with the results. It does not turn on when I connect it normally but turns on when the positive of the driver is connected to the body and the ground of the pill to the positive of the 18650. I tried the pill of the other C8 and it functions normally. I also rechecked the wiring using the stock driver as reference and the connections seem the same.
What have I done wrong? Did the long exposure to soldering iron heat damage my driver? I’m contemplating on replacing the 2 pairs of 7135 chips I bonded to each other. I still have 7 chips left.
Help please? :bigsmile:
Here’s the picture of the Convoy C8 driver with 2 7135 chips added. I followed OL’s technique of using hemostats to hold the driver and the chips together.
Sorry for the crappy picture. I have a crappy camera. :8)
Found the problem! |(
I almost lost hope when I took a closer look at the MPCB. The black wire was connected to the ’“+” of the MPCB and the red wire was connected to the “-”.
I don’t know if Convoy made a mistake or its technicians did that on purpose. 
I connected the black wire to the positive of the driver and the red to the negative and my light now works. The light output difference of the two Convoy C8s is not evident but the 10*7135 C8 gets hot a little faster than the stock (8*7135) C8.
You make so easy Ill give a shot!:-)
I cannot stick the blob of solder on my soldering iron tip, probably my tip has been oxidized. How do you guys maintaining the soldering iron tip in healthy condition?
Sal ammoniac (ammonium chloride). Your tip will be shinny as new.