need quick awnser on soldering

can aluminium wires be solder toghetter size 16 gages and with what type of solder
Thank you in advance.

Under well-controlled conditions with ideal solder and flux, aluminum wires can be soldered (in theory). As a practical matter, I think it is a waste of time to try it.

I have purchased a number of "aluminum solder" kits of special flux and solder over the years and have NEVER gotten the stuff to work! Some of the kits were "dime store" or hardware store kits and some were from welding suppliers and made by very reputable manufacturers. I have been soldering for about 60 years under all kinds of conditions with all kinds of materials, having started out with soldering "coppers" heated in a small furnace on the workbench in metal shop in junior high school. I have done a lot of brazing and silver soldering. I know how vital cleaning of the metals is and how important temperature control is. I have never successfully soft soldered aluminum. I'm sure others out there have done it successfully. Do not attempt to solder aluminum wires with conventional electrical solder and flux. It is a waste of time.

One foolproof way to do it is to use an ultrasonically excited soldering iron. This is a conventionally heated iron with the addition of ultrasonic excitation. The ultrasonic energy cleans the aluminum oxide off the surface to be soldered while the joint is under hot solder and flux. Under those conditions, solder bonds very well to the clean aluminum. Without the ultrasonic energy, the oxide forms almost instantly after cleaning the metal and the aluminum is very resistant to attack by flux and has a very high melting temperature.

Why do you want to solder aluminum WIRES? I doubt that a solder joint on aluminum wires is legal for any application subject to the electrical code, although that's just a guess. If you are joining aluminum wires in house wiring, you must use connectors specifically rated for joining aluminum wires and you should use anti-oxidant goop on the joint before making the connection.

awright

I have an idea which I have never tried because I have not got the need to yet.

It involves soldering a copper wire to a thin aluminium soft drink can so that it can be use as a shield of some sort.

I have tried in the past to do so using a simple soldering iron but the solder won't stick, for the very reasons mentioned clearly by awright.

My idea is to use a solder stick shaped like a rod so that I can clamp it to a hand drill with about 20mm extending outside of the jaw. After I clean the spot on the soft drink can using some abrasive material, I then smear a thin coat of flux paste over it. With the can well supported, next I would start the hand drill and press the tip of the soldering rod against the very spot. The heat generated from the rotation of the end of rod rubbing against the surface would eventually melt some of the solder and hopefully some of it would stick to some part of the aluminium surface. Then I can solder a wire to it afterwards.

Idea not tested and might not work. Any comment?

musthave said:

can aluminium wires be solder toghetter size 16 gages and with what type of solder
Thank you in advance.

Click to expand...

As already suggested, it's perfectly possible, but you need specific aluminium solder (which is freely available) - but it's NOT as easy as soldering copper wires together. You also need fairly substantial heat to make it work!.

A TIG welder will certainly join aluminum..... problem is, we are talking many amperes instead of wattage!

Minor typo in my post above: I meant to say that aluminum OXIDE is very resistant to flux...

Nigel, have you ever had any luck actually getting a bond with aluminum solder and flux? Is is possible that none of this stuff actually works and there is a whole industry feeding off our wishful thinking that it is possible, like free energy?

Well, one of the books out of my library that has not composted yet is, "Soldering Alcoa Aluminum," by, coincidentally, Alcoa. They make it seem like a slam dunk, but with a few cautionary notes. They recommend 95Zn-5Al solder or pure zinc solder and Alcoa flux #66A, which they describe as a high zinc-chloride flux. They emphasize the importance of not overheating the flux, either with a flame or an iron, both of which they say can be used. Overheating the flux produces reaction products that block solder bonding. If a flame is used, it must be a reducing flame, i.e., a slight excess of fuel relative to oxygen. This is easy to obtain with an oxy-fuel torch, but I don't know how you would obtain it with a standard propane torch without separate oxygen control. Maybe by blocking off some of the air intake ports.

They say conventional soldering irons and guns can be used with low-temperature solder #408 and Alcoa #64 flux, with the precaution that the iron should be kept out of contact with the flux to avoid charring the flux. The iron can be tinned with tin-lead solder, so I guess there is no problem with "lead poisoning" of aluminum solder.

Hi eblc1388: Method #10 in their "Methods.." chapter is "Rub soldering or solder coating." They say the solder "easily" (Hah!) wets the fresh metal surface that has been rubbed with a solder stick or iron or wire brush or glass fiber brush or scraper. This is using heat from a torch, iron, or hot plate, not froction alone. I think you might have difficulty doing it without some external heat. (On the other hand, I think you will have difficulty doing it with ANY technique or materials. Do I sound bitter?)

Good luck.

awright

awright said:

Nigel, have you ever had any luck actually getting a bond with aluminum solder and flux?

Click to expand...

Yes, I've used Multicore Aluminium solder on a number of occasions over the years, it also works on stainless steel.

As with any soldering (but even more so) you need to ensure the surfaces are completely clean, and then do the soldering immediately.

Just tried a google search and I see that Multicore forwards to Loctite - and I couldn't find any suitable solder listed there? - perhaps the lead free requirements have killed it off?.

Tank’s guys for the input very appreciated. its not for me, a friend of mine got a GM car with an aluminum wiring harness for the rear lights a wire broke he tried a crimp but splice and it doesn’t last dissimilar metal, I told him to replace that wiring with copper as a winter project but its to involve for him that’s why I was inquiring about soldering it and sealing the joint.

The crimp may have lasted if you had used anti-oxidant goop on the joint before crimping, even with copper connectors. Also, you may be able to find a crimp ferrule compatible with aluminum wire, but I've never seen them (or looked for them). I'm amazed that an auto manufacturer would use aluminum wire because it is far more subject to fatigue failure than copper.

Go to a contractor's electrical supply house and ask for wire connectors compatible with aluminum wire. And use goop. And use tape to support the wires together outboard of the actual connector to avoid fatigue failure at the point of gripping of the wire.

awright

By the way, a lot of random discussion and time could have been saved if you had revealed what the application was at the outset, rather than making us guess.