I plan on reflowing my xp-g2 from AL to a Sinkpad I got. On youtube, people use solder paste… Do I need solder paste? The only thing I have is rosin core solder. I plan on driving my xpg2(Dedomed S2 B2) with 4A and burst 5A on C8 reflector. I want to build a flashlight with maximum throw, so c8 reflector or a 50mm asperic lens would do the best? Any suggestions on soldering procedures for Xpg2 on Sinpad on End of copper pipe cap On 15 (already soldered pre 1980 pennies), then I would solder the cap to a copper pipe. I hear people say the build up heat would destroy my Led before the solder even cools. I am not sure what to do here. I can post pictures(kinda annoying everytime I post pictures becuase my phone has no usb o.o) if my explanation is not good enough.
Addicted to building flashlights. 0 money left lol
Well you might get away without using any at all. If you are lucky there will be enough solder left on the old one to do the trick. If not you can take a very tiny bit of solder and put it on the sinkpad and put that on a pan on the stove top use a medium temp not too high and wait for the solder to melt and then place your emitter on it. I use a set of hemo’s. I can’t say for sure this will work as I use solder paste but I don’t see why it wouldn’t. Just don’t get your sinkpad too hot or the plastic on top will burn. But I think you should be able to get the solder to melt before the plastic. You will know that the plastic is getting too hot because it will start to turn brown. (Don’t ask me how I know this, lol)
A lot of people put the solder paste on and then the emitter and heat it together and wait until the emitter kind of settle into place. I don’t do that. I put the solder paste on the emitter and only after it’s melted do I place the emitter on top of the sinkpad.
If it looks like you have too much solder on you can pick the sinkpad up and turn it horizontal and tap it. The solder will bead up and roll off, leaving the right amount. If it doesn’t work on the first attempt, try it again until it does. One of the biggest things is to make sure you have the same thickness of solder on the center and both sides. If the center has too much and the sides too little it won’t make good contact.
Good luck and if you have any trouble you can PM me and I’ll be glad to help if I can.
To he honest, I have no idea what a “C8” is. I think it is the size of a flashlight? The reflector I got is sold by itself. I dont have any flashlight hosts at all. I build my own.
So when i get sinkpad, I plan to solder the Sinkpad on top of that copper Cap, solder the penny hunk underneath it, add globs of cheap thermal stuff I got real cheap, add driver, then finally solder the pipe to the cap. I have a soldering gun, iron (25W), and that torch in the picture. I soldered my pennies together with that torch (was really easy since I just blasted those pennies with heat and everything melted nicely). The problem here is that I dont know what order I should do these in. If I do Sinkpad on Cap on Penny on driver on pipe, then if I put the LED on last, would there be too much heat before everything cooled down and my LED would fry? I heard somewhere that my LED would fry if it is left at soldering temps for too long.
Aucutally, all this can be avoided if I just used arctic silver, but people say soldering is 10x better and if I plan to run at 5A, arctic silver might not be good enough.
That is a tough questions really. I haven’t lost any emitters to high heat in the reflow process but I don’t let them get hot out of caution. Also I know that I have ran 5amps with thermal epoxy but I use better stuff than arctic stuff. However, I believe that as long as you do a good job lapping the star to the copper and use a thin even layer of arctic you will be good to go.
Air is your biggest problem because it’s such a good insulator. What I would do is make sure to lap them together really well. Sand the bottom of the star and the top of the copper until both are perfect matches and shiny. Use very fine sandpaper. You can make sure they are matching by taking some marker or something like that and putting it on the star. Put the star in place. If the marker doesn’t come off onto the pipe evenly then you know you will have an air pocket. If they are perfectly lapped together and you use a thin coat of toothpaste it will be fine. I’m joking about the toothpaste but only kind of. It would work until it dries up and cracks.
Like I said the biggest enemy is air, remove the air and use as this a layer as possible and 5amps will be no problem at all. I drive them beyond that without solder all the time.
thank you so much for your insight. I got fine grit sand paper, I think it is 2000 or 3000 used for cars lol. But do you think drilling 2 holes and using screws will work? how about 4 holes? X; SO HARD TO DRILL. Do you have any ideas of getting that led to stick on? I am not sure how AS works. Is it true that if i let it sit for long time, it hardens is there any kind of material where it sticks even when running high heat? thanks. Oh yeah, I remember arctic alumina, I might use that but it will be permanent >.<
Tapping holes is actually great if you can do it. Two should be fine. I have not used arctic stuff at all actually. I use some really great epoxy that will hold about anything down, but it’s $40 for the two tubes. I’m sure that someone will come along with a tip. I also know a few people have used good old JB Weld but I don’t know if you can get it thin enough. Also if the reflector is going to be pushing down hard enough, the Arctic stuff will be ok too. What I notice is that when they are lapped together good and a think coat is applied they kind of stick together anyway even if you are just using something like Fujik it’s almost like suction in a way.
Good luck by the way, it sounds like a fun project.
I will tell you I have soldered nichia, xp-g2, xm-l, and xm-l2 on cheap and sinkpad mcpcb's using regular rosin core solder many times. Hardest thing is doing the sinkpad, as they are very thick, and have to hold my solder iron underneath them a lot longer than the cheap mcpcb to heat up the solder on the other side.
Regular 60/40 solder works fine but if you have any emitters you’re not overly fond of practice on one of those first. You can reuse stars as long as they don’t get so hot they delaminate. Slight darkening of the solder mask isn’t a problem. While you’re at it pretin the +/- pads with a small bump of solder. A pan on the stove (low heat but cooktops vary) or a good iron held against the bottom of the star will do the trick. Even a small pencil torch will work but it’s easy to burn something with one.
