# Working with speaker wire



## Jack N (Oct 7, 2006)

I'm in the process of wiring my home theater and I need to solder two pieces of 8ga speaker wire together. I haven't been able to get enough heat into the wire to get the solder to melt - there's just too much surface area that dissipates the heat. I've tried using an electric soldering iron, and then a butane micro torch with a soldering iron attachment but neither method has worked. My only remaining option is to use a direct flame from the micro torch directly but I'm not fond of that idea. I'll try it if it turns out to be my only option. I'm looking for some more ideas.


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## tonyvdb (Sep 5, 2007)

have you put solder paste (Flux) on the two sections you want to solder together?


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## Jack N (Oct 7, 2006)

No. I'm using resin core.


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## willis7469 (Jan 31, 2014)

Try the electric iron, and a heat gun or hair dryer at close distance to hold/transfer the heat. Not too close to melt the jacket though. Bernzomatic torch? Are you gonna heat shrink over the joint?


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## tonyvdb (Sep 5, 2007)

Jack N said:


> No. I'm using resin core.


Resin core works on small awg wire but you will get better results if you buy a tin of the stuff and actually dip the ends of the wire into it and then apply heat and solder. It will pull the solder into the core of the wires.


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## Jack N (Oct 7, 2006)

Willis7469 – Bernzomatic torch? Yes. Heat shrink? No. The solder joint is straight wire with an inch of insulation stripped away and another wire coming in perpendicular to the first wire so the connection is shaped like a “ T ”.

Tonyvdb – I understand what you’re saying but the problem is getting enough heat into the wires to get the solder to melt in the first place. If the solder doesn’t melt, flux is a moot point.


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## mikeyb128 (Dec 25, 2014)

I went to automotive school up here in Canada and we get heavy instruction of electrical including how to properly solder. One tip is to put a dab of solder on the iron then hold the iron with the dab touching the wires you wish to solder together, the heat transfers from the iron to the solder, from the solder directly into the wire. You then hold the solder to the wire and not the iron, the solder will "suck" into the wire. It takes some practice but is really easy, and rosin core will work really well. If you are soldering critical parts then heat sinks and adjustable temp solder irons are recommended. With speaker wire you are safe! 8 awg is pretty heavy so you might want a higher wattage iron. This may be your problem.


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## Jdiesel87 (Oct 30, 2013)

What kind of tip does your soldering iron have? I find the the extra surface area of a flat tip helps transfer the heat much better.


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## Jack N (Oct 7, 2006)

Mikeyb128 – Good tip. Thanks. I’ll give it a try.

Jdiesel87 – Yes, it does have a flat tip. I also tried a smaller flat tip hoping the heat would be more concentrated.


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## Andre (Feb 15, 2010)

I solder very few things, I prefer to "twist and crimp", but thats a personal preference. There are some excellent tips here.

The flux for one, tinning the end of your iron another, coat each wire individually then melt them together.


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## tonyvdb (Sep 5, 2007)

I always heat from the bottom of the wire and apply solder to the top and it pulls it through. Ive done up to 12awg wire with no issues using a 35watt Weller iron with a pointed tip.


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## Andre (Feb 15, 2010)

You can also try a lower melting point solder


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## Wayne A. Pflughaupt (Apr 13, 2006)

Jack N said:


> My only remaining option is to use a direct flame from the micro torch directly but I'm not fond of that idea. I'll try it if it turns out to be my only option.


For eight-gauge wire, there will be no other option, for soldering at least. The million dollar question is if the insulation will take the heat. I’m guessing it won’t.

There are better options for splicing wire that thick than soldering. You should be able to adapt a coupler of some kind designed for car audio use that will have a pressure (screw terminal) connection. Probably your best bet, as I doubt you can find a twist-on wire nut for wire that large, and butt splices in that size are industrial fare that will require special crimping tools.

BTW, there’s no good reason to use eight-gauge speaker wire, especially if the individual drivers in the speaker are 4-ohm or greater.

Regards, 
Wayne


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## lcaillo (May 2, 2006)

To solder large wire you have to have a very large tip to hold enough heat or use a solder pot.


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## Steeve-O (Dec 3, 2010)

Read this : http://www.rctech.net/forum/radio-electronics/336870-how-solder-correctly-not-so-brief-lesson.html

I solder my RC car LiPo battery that use 8 gauge wire with my Hakko 936 clone soldering station and each solder take a maximum of 10-15 second for this wire (which is insanely long to me). 

The trick is to have a not too bad iron with an as large soldering tip as you can physically fit where you have to solder. Flux also help and lead solder while being toxic work much better (just wash your hand corrently, don't touch your mouth, etc). Usually iron temps should be between 650 and 700F for leaded solder. Wick your tips as the molten solder transfert all the heat.


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## maughanaudio (Jan 12, 2015)

You need to use a good soldering iron such as the Weller which accepts PTE8 tips or a soldering gun such as a Weller 8200PK soldering gun. Also if the wire is multi-stranded litz, you need a soldering pot to burn off the varnish insulation. I personally would recommend using some T&B Butt crimp connectors, but then you need to have the right crimping tool, plus the right size butt connector for the wire gauge. Don't settle for cheap connectors sold at Radio Shack or most auto part stores. To do a good solder job on heavy gauge wires, lay the stripped ends next to each other, then take a separate 18-24 gauge solid bare wire and spiral wrap around the two connectors to make a tight mechanical connection and then solder.


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## Jack N (Oct 7, 2006)

Tonyvdb – That’s how I’ve always done it (except for using a flat tip instead of pointed) in the past and its always worked so I was little surprised when I couldn’t get anywhere this time around. I thought I might have some trouble with the heavy gauge but thought I would eventually be able to solder it. Not so.

Andre – I’m using 40/60 to get better electrical conductivity. I realize that the melting point is 60 deg higher, but would prefer to exhaust all other options before going to a 60/40.

Wayne – You are correct. I tried using a direct flame and the insulation will not take the heat. Not only does it melt, it wants to catch fire and thus I end up getting a lot of black soot in the joint. Unless I can get better at controlling the temp of the wire and aiming the heat source, direct flame probably isn’t going to work.

Before making the decision to solder I literally went to six different stores trying to find a coupler, splitter, or anything that would work. I didn’t have any luck. Although I did find wire nuts that might work, I don’t feel comfortable using them on stranded wire. I've been thinking about using a crimp on connector on the end of each wire and then bolting them together.

I’m not an electrical genius by any means so I have done some research on wire gauge. Please feel free to correct me if I’m wrong. I know that wire gauge is directly tied to the length of the run, and load. Load level will probably be 4 ohms, and the run length will be somewhere around 60ft. According to generic charts that I’ve seen, 10ga would suffice. I decided to go 1 size heavier figuring it’s better to be safe than sorry.

Lcaillo – Solder pot! There’s an idea!

Steeve-O – Looks like a good article. Thanks. I’ll finish reading it at work tomorrow.

Maughanaudio – I have a Weller iron that uses a similar tip. I thought about trying the 8200 but decided not to because it’s only 10 more watts than the one I have when I put it on high temp.


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## lcaillo (May 2, 2006)

The conductivity difference in solder is essentially meaningless. 63/37 actually has the lowest melting point. Using a 40/60 is most of your problem. That is worse in terms of heat needed than lead free solder. That much difference in the melting point with the heat sinking of the large wire is tough to overcome.


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## chashint (Jan 12, 2011)

63/37 is definitely the right choice for solder.
In addition to lower melting point it transitions from liquid to solid much faster than 60/40.

Heat shrink is insulation (electrical) that is a tube. You slip it over the wire, solder, move it to cover the exposed wire, apply heat to the shrink tube and it shrinks to fit.
Its mu h better than electrical tape.

I would recommend sitting the wires parallel to each other instead of perpendicular.
The larger surface area where the eires touch will make a better joint.

I would recommend using the largest flat tip you can fit into your iron.
Apply solder to the tip and let that solder conduct heat to the wire.
Continuously feed solder into the joint between the tip and the wire.

Pretin each wire separately by melting solder into it until it is full of solder measured from the end of the wire two - four times the diameter of the wire.

If you have a real heat gun it will be a big help. I don't think a blow dryer will help you.

If you have lintz wire the recommended solder pot will be required to melt away the insulation on the individual strands of wire.


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## Andre (Feb 15, 2010)

8 Gauge?? imho, serious overkill.

http://www.audioholics.com/audio-video-cables/speaker-cable-gauge


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## Wayne A. Pflughaupt (Apr 13, 2006)

Keep in mind that in splicing the two wires, no matter what the method (twisting them or laying them side by side) you’re more than doubling the numeric gauge. Basically you’re dealing with 3-gauge wire, something akin to the battery cables on your car. I just don’t see any electric soldering device working with something like that. I’d suggest ditching the 8 and getting 10-guage. You could probably use common electrical wire nuts with that.

Regards, 
Wayne


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## istvan (Jul 5, 2013)

I use a weller http://www.weller-toolsus.com/soldering/guns/weller-d550-gun-soldering-professional-d550.html.
Using extension cords can be problematical. Clean tip. solder on tip first. Should melt on contact. Touch wire. Solder to wire. Should flow into wires. 

If you are not getting heat it may be because your using extension cords or your contacts are corroded.


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## chashint (Jan 12, 2011)

I question #8 wire too, #12 would be my choice.


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## Jack N (Oct 7, 2006)

Lcaillo – Are you saying that tin and lead have about the same conductivity? If so I’ll gladly switch, but then what is the purpose of having different ratios available?

Andre – The link you supplied to an article verifies what I’ve found elsewhere. Table 1 in that article shows that 10ga would be at its’ limit for my installation. That’s why I decided to go 8ga to be on the safe side. Ya, it costs more and is obviously harder to work with, but once the walls/ceiling are sealed up there’s no fixing undersized wire.

Wayne – Interesting observation/comparison. An eye opener to be sure. I plan on trying some of the soldering tips that people have listed this weekend. But if I’m unable to solder them, would doing something like what I’ve done in the picture be ok? Or would the signal be compromised?

Istvan – I wasn’t using an extension cord. I’ve learned to avoid them in heavy load applications (it cost me a nice drill once). Have you tried soldering 8ga speaker wire with that gun?

Chashint – 12ga would be far too small for my application. Take a look at the table in Andres’ link.


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## chashint (Jan 12, 2011)

To be blunt, that table is not accurate.
The article draws conclusions not supported by theory when you take 20kHz and below into consideration
Much of what is bantered about is not applicable.

In whole numbers if the load is 4 ohms, 500 watts is 45 volts @ just over 11 amps.
If this application is home theater that is a worst case scenario situation.
AWG 12 is more than you need.

BTW what is the picture of the three wires supposed to be?

I think a better description of what you are attempting to do would be a good idea.


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## chashint (Jan 12, 2011)

Conductivity of solder is measured in micro ohms, in the real world where you are connecting wires to terminals or plugs all solder is equally conductive.
Don't get hung up on the minutiae of the different conductivity of the various solders.

There are different ratios because industry needs solder to do different things during the manufacturing processes.

Due to the worldwide lead free initiative things are changing, but 63/37 has been and is the industry standard for hand solder assembly and repair of electronic assemblies.
It has a low melting point and the transition from liquid to solid is very quick.
It is very important that the joint is not moved during the solidification stage or the solder will fracture and fail.


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## Axiomite (Dec 18, 2013)

Given that the #12 AWG would be more than you need it seems like the easiest thing to do would be to use that rather than putting so much time into this soldering endevor.


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## Jack N (Oct 7, 2006)

Chashint – Thanks for all the info. I found out that there’s a store about 8-10 miles away that carries 63/37 solder. I’ll pick some up and give it a try.

The picture is for a question that I asked Wayne in the same post. If I’m unable to do a good job of soldering, would that type of connection be acceptable or would it degrade the signal too much?


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## tonyvdb (Sep 5, 2007)

That connection would be just fine, you could even solder everything together just for that added solid connection. If you look one line you can even find those crimp connectors gold plated.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Jack N said:


> Wayne – Interesting observation/comparison. An eye opener to be sure. I plan on trying some of the soldering tips that people have listed this weekend. But if I’m unable to solder them, would doing something like what I’ve done in the picture be ok? Or would the signal be compromised?


Is this a mock-up or is it the actual wire you’re using? The reason I ask, those yellow lugs won’t accept anything larger than 10-gauge wire. If that is the wire you're using, you can use couplers instead (aka "butt splices"), and you won't need a bizarre set-up like that.

If this is not the wire you’re using, and you‘re going to use a similar crimp-on terminal designed for 8-gauge wire, then you might as well just use a butt splice instead of the ring lugs shown in your picture. But as I mentioned before, you won’t be able to crimp those things with your typical hardware store crimper.

If you’re really serious about this and don’t want to spring for an industrial-grade crimping tool, I suggest using a coupler such as the one pictured below from a local car audio dealer.











Also, if you’re using wire like in your picture with the clear jacket, that stuff isn’t supposed to be used in-wall.

Regards, 
Wayne


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