Soldering copper braid to aluminum... Success!

Hello everyone!

I just wanted to share that I was able to solder a piece of copper braid to the aluminum tail cap of a TX25C2 to reduce the resistance from the spring, it was not difficult at all! I think this can help in high amperage lights to reduce resistance and get more amps flowing.

I basically followed this guy’s video but made a small change

What I did is just replace the motor oil with soldering flux, lots of soldering flux! I first cleaned the aluminum of all oils using acetone, then alcohol, then I used a small sanding pad to make a semi rough surface, then used about a dime size of soldering flux, melted it with the soldering iron and while it was liquid i scraped with a metal owl the surface making sure that the aluminum surface is covered with the flux and has no contact with air.

then I heated some solder using the iron and rubbed it against the aluminum surface, at first it seemed that it was not working but after a few seconds rubbing the tail cap with the solder I noticed that a small black cloud began to form on the surface of the flux and the solder adhered to the aluminum, I tested by trying to scrape it off the aluminum and it doesn’t move at all.

I then proceeded to solder the braid,

I tested that the solder was still holding by pulling on the braid but the solder held nicely, that braid is going nowhere!

I then put just a tiny bit of solder in the tip of the spring

Then inserted the spring and compressed it a little before soldering, soldered the braid to the end of the spring, cut any excess braid and you are done.

Hope it helps anyone who wants to try it!


…you possess the power…of the GLOW! :bigsmile:

I love reading posts like this… Always great to have another tool in the toolbox. Thanks!

thanks ,i’ll try tomorrow.

Orsm. I have trouble getting solder to stick to what its supposed to let alone what its not supposed to.

Nice to know, very useful! Thanks for trying and sharing.

cool, very usefull techniqe, how strong is the bond? if you pull it will the brade come off, or it is stock there firm? i have tried soldering to AL. before, i got the wire soldered, but a light pull and it came off.

This could be quite useful.

Biggest problem I’ve had soldering to aluminum has been with floating drivers in small zoomies. A Sipik 58 or Cree 3W might not have enough room for a replacement driver inside the pill, but this can be solved by floating a driver below the pill.

The downside is how to get a reliable negative connection between the driver and pill. Currently I solder a wire to the driver, then drill a small whole through the side of the pill, stuff the wire through, then solder around the wire. Enough to get an electrical connection from tension, even though the wire isn’t actually soldered to the pill.

Being able to actually solder the wire would make for a better connection.

I tried to scrape off the blob of solder on the tail cap using my fingernail and a wooden toothpick and it will not come off, in the third pic the tailcap is hanging by the braid, I pulled on it hard and it did not come off either. I think that is good enough for what I need it to do.

LEAD-tin solder is getting harder to come by. Heck, in the good old days thats all there was, lol… i still have a little stash here SOMEwhere, dont know where but there SHOULD be…

everything today brags how “lead free” it is? and it makes me wanna puke, lol…

whats LEAD resistance? they might use it for battery terminals in all cars for a reason, lol… man you can get hot lead to stick to almost ANYthing.

plumbers poured floors with it, car repair guys that could do the lead repairs on the steel cars,it made the solder easy to work with.

naturally they had to do away with lead, it was far too useful…

Thanks for this AlexGT :slight_smile:

I had been meaning to research if this was possible somehow, for a similar reason you did it, i want to improve the connection in the switch, by not only pressing the - tab of the switch against the body, but solder it on maybe by wire to lower the resistance. Just like we lower the resistance by wire bypassing the springs.

I think it may be possible to reflow a copper mcpcb onto a aluminum pill/shelf, if we pre solder a layer of solder by removing as much as the aluminum oxide & pre threat it with motor oil like he does in the video & then reflow the mcpcb on to that solder.

After reading the reviews I ordered one to try.

It’s looks very goot!

I've been thinking about this for a while now too and thought about drilling a hole in the side of the pill ...Adding a small pin of copper or brass like a rivet ... and then hammering it to squish it ...making it squeeze tighter in the hole . then cutting a slit(hacksaw or a dremmel cutting wheel)from the top of the pill down to the pin in the side of the pill . then filling the slot with wire,flux,solder to the top ....>>>>> 0=l

That might be worth trying.

Couple other things I do after stuffing the wire through the hole and applying a blob of solder to the outside so it can’t fall out:

  • I sand it flat if necessary. Can’t have it getting in the way of the screw threads when the pill is screwed in.
  • I anchor the wire in place using conductive silver epoxy. I’m sure the epoxy I use has more resistance than solder so I try to maximize actual solder contact, but this technique seems to do the job. The epoxy I use is stuff I got from Fry’s. Wasn’t cheap, but works well. It’s also great for connecting the wire from an e-switch to the body tube (necessary step in converting a tailcap clicky into an electronic sideswitch).

I wonder if this technique is worth trying:

Copper plating aluminum

Was this the one?

Sorry that’s what happens when I get bored.

Seriously though awesome info. I will give this a try.

Nope! It was this one :smiley:

You sir have earned free 12 pack the next I am in Texas. Well played.


Necroing this a bit…

Recently goot this:

And so far, neither is super nor is soldering, though it seems to flux.

0K, enough with such a cheap joke. So far, I've applied it with the tip of the solder wire and I've also blowtorch heated up the whole stuff with the solder inmersed in the flux, to no avail. Seems I'll have to try leaving the flux working over the aluminium oxide layer for a certain while, doesn't it?

Soldering alu seems really bitchy…

Cheers ^:)