"Modding 101" questions

OK, I'm a soldering noobie, but I have a light I need to repair. I need to attach a new driver to an XM-L for my trustfire F15. The driver (from shiningbeam) has the wires already attached to it.

My question is this; On the emitter, there are 6 shiny pads that look like soldering points. Do I have to attach the new wires to the same pads where the old wires were? Or can I use the ones next to them?

I ask because since my soldering skills are basically non-existent, my de-soldering skill rank roughly the same. Maybe others can use this thread for noobie soldering questions as well...

The other pads are also conductive so it will be ok. just follow the + & - markers.

That is what I was hoping the answer is, thanks. Also, should I mess with that blob of solder on the side of the emitter, or just leave it alone? Don't know how fragile that dome is.

I have knocked off the domes before on XR-E by mishandling them. You may just be able to wipe off the solder with a light cloth, try not to move the dome sideways....

it should actually be easier to remove the old wire and solder the new wire on the same pad.

if you're having trouble removing the old wire, you really should practice soldering on something non-critical first, because removing the wire should be the easiest thing to do. all it involves is getting enough heat on the pad to melt the solder. if you can't do that, then something is wrong, and it won't be any easier soldering on the other pads.

I haven't tried any of it yet. Waiting for my solder, and flux from DX, and ordered a desoldering wick as well, since they were cheap. Just trying to prepare for the day when it arrives.

If you have a half decent meter (even the free ones from Harbor freight work), the diode setting should light up the emitter a bit so you can check to be sure.

I highly recommend this stuff:


It's also available from DX. It has the flux mixed with the solder and makes soldering and tinning wires extremely easy. You can use a toothpick to apply small quantities directly onto the pads of an emitter. I use this extensively with great results.

Can you explain how solder paste works? It sounds like a thick but fluid paste that you just put where you want to solder and it hardens once heat is applied and allowed to cool like normal solder?

If thats the case i could see me buying it and at least trying it.

sounds like its a powdered solder, mixed into a flux paste. add a dab, heat and let cool. if thats what it is, then i need some. im bad at adding too much solder to the joint

EDIT: http://en.wikipedia.org/wiki/Solder_paste

sounds like i was right, gotta get some. plus it would save a hand from feeding the solder

Definitely get some. I am somewhat experienced with soldering, from tinkering with electronics almost my entire life, and even had to take a college electronics class where soldering was taught. Even so, I still keep a pot of the paste handy because it is so easy to use. The deal from DX/MF is really good; I bought a tube about 1/10 the size from a local electronics store and it cost $8 IIRC. I try to keep the tub in the refrigerator (it has a warning on the side to keep it cool), otherwise, it tends to harden in the tub after a year or so.

Also, I want to try this with reflow-type soldering emitters on a bare star board. Put tiny dots where the contacts will be, then heat on a flat stove-top to melt the solder...

I'm quite experienced in soldering and I've learned NOT to use solder paste with a soldering iron. Yes, you can make it work but it spatters everywhere and the flux doesn't work the way it was designed. If you have good luck doing this, then by all means continue, at the end of the day a good solder joint is a good solder joint, regardless how you do it.

Solder paste is little uniform sized balls of solder mixed with a paste flux. It is designed to be screen printed onto a PCB (think of a silk screened tee-shirt), and reflow soldered in a reflow oven (either forced hot air or infra-red). This way the flux melts first, cleaning oxides from the solder joint, then the solder melts - on all the joints at once.

One thing I've noticed that makes soldering difficult is the switch to lead-free solder. We in USA may still use Tin/Lead solder which melts at a lower temperature and leaves a very shiny joint. Lead-free solder requires higher temperatures (which can cause problems for the parts your soldering if they get too hot) and tends to go through a "paste" phase as it cools leaving a grainy surface.

But enough theory, if paste works for you, use it. I use 0.015" diameter wire solder for hand soldering, solder paste for reflow soldering (in a toaster-oven!), and I use lead-free for the blobs of solder on the battery contact area of driver boards. It is harder than Tin/Lead solder and doesn't deform as much.

Troop do yourself a favor and take your time to much heat will dedome the emitter and then you are done.

1. Definitely clean the pads with alcohol, any of them will work as long as you use one + and one -.

2. Solder one at a time, let it cool for a while than do the other. This is very important when you first start out so you don't overheat the emitter and dedome it.

3. If you have a shaky hand try to rest it on the table while soldering so you don't slip and hit the dome and burn it.

4. Bend the wires so they rest on the pad exactly were you want to solder to, this is important so you can be quick and avoid overheating the emitter.

5. Drip a small amount of solder on the pad you are going to use to make sure it sticks. Let it cool then pick at it with your finger and make sure you have good adhesion. That way when you solder the wire on the blob of solder encapsulating the wire has something to stick to besides the smooth pad surface.

6. Take a break after one wire is soldered on and let the emitter cool down. Scrape at the attached wire and make sure it has good adhesion. Once the emitters is cooled off solder the other wire and you should be good.

7. Good luck soldering is not easy for everyone, I had a very hard time and it took me quite some time before I became proficient at it.

8.Avoid lead free solder like the plague.

Great tips, thank you.

Update. OK, this did not start off well. The first part of this project is to get the driver firmly adhered to the brass pill. Trustfire's failure to do this is what caused the original problem. Trying to solder to brass I'm guessing is not easy or takes some special components? I end up with little 'balls' of solder that don't want to adhere to either the driver or the brass pill

The brass is glued into the SS tube, so I have to work on this inside of the stainless steel tube. I also had to use a dremel took to grind out some of the brass so the shiningbeam driver would seat in it...

I can grab the solder balls with needlenose pliers and pull them off the brass, so I'm not getting a good joint there.

Try roughing up the brass with some sandpaper or a file to create more surface area than clean it with IPA to create some surface tension than try it again.

I use Radio shack rosin soldering paste flux than paint a little on the brass were you want the solder to stick let it dry a little than heat the brass than hopefully the solder will stick. This can be quite aggravating.

I usually prefit the driver so it is slightly over sized and needs to be press fit into the pill to hold it in place while soldering. If it fits loose put a small glob of solder on the edge of the driver so it fits tightly in the pill to hold it in place that might help a little.

Make the brass hotter and it should stick.

Trooplewis , I am watching this thread .

If you succeed in this adventure , I am going to try the exact same mod .

So good luck .

Good news...sort of. The F15 is working again. I did a rather indelicate job of soldering the driver to the brass pill, but it is in there solid. Got the wires soldered to the + and - pads of the emitter, added some Artic Silver between the emitter and pill, and voila', the light works again.

The bad news is that in the process of wiring the driver to the emitter, I got distracted by something and the soldering iron tip made contact with the emitter dome. Emitter still works, but not as bright as it used to be...oops. Doubt it will last long in that condition, but who knows?

At any rate, with about $25 invested in mediocre soldering equipemt, my $25 light is somewhat functional.

It is NOT the light I would trust in that life/death situation mentioned in another thread!

LOL, even with the SMO reflector in my F15, I think I now have the widest hotspot ever to come out of an XM-L. My 1.0A V-shark out-throws it, but wow, the F15 now puts out a wall of light.