Soldering of joints and terminals - To do or Not to do -Your view.

My preference is to crimp connectors and then solder over the tip. Main reason is to prevent solder running down the wire, causing it to fray downstream from the connector.

I also tend to solder fuses rather than put them in a holder - had too many holders rust out, especially near batteries.

I always solder any eye type terminals after crimping especially near batteries.
Normal crimp connectors I just crimp them and if they are outside I tape them with self amalgamating tape.

As said,If you solder correctly the joint will not fail, only problem can be the wire breaking if subject to to much movement.

If you crimp and use the good quality crimpers and the ones designe for that size cable it will not fail, the exception is corrosion water/battery acid and mud.

Have tried Deutscher plugs under water to 1metre and no water got into the plugs.

Sparkies use crimp lugs and links on large cables with no problems, the only difference is the higher vottage lugs and links are better quality and stronger.

Have a good one

Tony,
as you say "When I got into doing my own auto electrical work HE SHOWED ME HOW TO DO IT"

Yes, when they are done correctly they don't cause issues.
It's only when they are done poorly and left unsupported that problems will occur.

Mainey . . .

The argument against soldering seems to revolve around corrosion developing in joints as a result of chemicals used in fluxes including the resin core types. I know a man who is an ex Navy electronics specialists and he has published a number of books on EFI and converting old carburettor engines. I have seem him warn people against soldering on two Internet forums. During the forty seven years I have been using solder though, I have noticed a few changes in procedures.

When I started work in the auto industry in 1961, I worked with an ex RAAF WW2 aircraft electrician. He loaned me his original training manuals and they were full of soldered joints on terminals and splices.

In the 1970s when I was in the RAAF, it was all crimping. Soldering was only for printed circuit boards.

I have a genuine Holden workshop manual covering the wiring diagrams for the VP and VQ series 2 Commodores. A section of it shows how to replace a length of damaged wiring by splicing a new piece into it. It says put the wires into a joiner and both crimp and solder them.

I have always soldered all terminals and joins and have never had a problem so I will continue doing it. If corrosion can be a problem then it must take a hell of a long time to show up.

In the years I have spent working on cars, I can not recall seeing a faulty crimped connection inside a car but I have found plenty in areas subjected to dust, mud and water. Crimping only may be fine on ships and planes but not under cars.

I agree cleanliness is critical with soldering and the joint must not be allowed to move while the solder is cooling.

Brian

I spent some time in the RAAF as a Radio Technician. Part of the course you HAD to pass was HRHS (High Reliabilty Hand Soldering).
If a solder joint is done properly it will give many years of fault free service. However, sometimes it is not practical to solder a joint for a variety of reason, not the least of which is how much heat is required. Attempting to solder heavy gauge starting cables without the proper equipment for example can lead to a poor joint through not enough localised heat, and also to insulation damage from using an underrated heat source for too long, attempting to get enough heat into the wire for the solder to take. This can also lead to too much flux melting from the solder and wicking up the wire, which will cause corrosion and premature failure of the joint.
Conversely, attempting to solder a very small joint (such as on a cct board) using too much heat (soldering iron too big and not temperature controlled) can have disastrous consequences to the item being soldered

Another reason is crimp connectors are designed to make a good electrical connection by the very action of squashing the conductors, causing more metal to metal contact within the crimp, leading to a better joint electrically. Pre-soldering a wire and then crimping it will lead to a smaller metal to metal contact as the wire will not crush. This makes for a poorer joint electrically. It MAY be stronger mechanically but it won't be as good electrically.

So it's horses for courses really. If you use a crimp joint and properly insulate it you'll have no problems. If you look under your bonnet at your starter motor cables you'll find they're crimped, not soldered, and that can be a pretty hostile environment, and those joints generally last the lifetime of the vehicle.

The arguement against soldering is because it reduces the flexability of the wire and vibration and fatigue will cause it to break.
If you do solder it is vital that the cable is properly supported both side of the joint.
For the same reason, you should never use household type cable n a vehicle. It is not as flexible. It is likely to break. Soft, multi-strand is much better in vehicles.

You will never see a commercially soldered joint on a vehicle, even absolute top of the line ones, so it has nothing to do with cost.

But to get good crimped joints requires a good quality crimping tool, not the type that most of us use.

Cheers,
Peter
OKA196 Motorhome

If you are using a crimp lug, then crimp it.....but only if the wire is the same size as the lug..

As an example, I solder wires into an anderson plug, because a 13.5mm wire is too small to crimp into a 16mm lug !! And when crimping something the size of 16mm ( or bigger ) you really need hydraulic crimpers..( which I don't have lying around at home )

Easiest way is to get your wire lengths and lugs to suit and go to an auto lec and get them crimped properly..

I agree with everything above, however, if the wire is to connect into a screwed terminal, such as a trailer plug where the screw tightens directly against the wire, the general rule is NOT to solder. This is because solder (basically lead)will over time, distort and cause the connection to loosen, especially where there is movement of the wires. I have seen this happen many times. Other joints and crimped connectors (soldered afterwards, NOT tinning of wires before crimping) - no worries.
Cheers
Gerry

If you don't have the right skills, tools and materials, then don't crimp.

If you don't have the right skills, tools and materials, then don't solder.
.

Hi All,

I think Mike (above) has hit the nail right on the head. Just about all electrical joint problems arise because of 'operator' problems , not 'method' problems.

My background is in mining & industrial electrical/instrumentation wiring. In this field, crimp connections reign supreme and have done for some decades, despite having to survive in extremes of dirt, dust, moisture and (especially) vibration. Except perhaps for marine, salt-corrosion environments, I'd go for PROPER crimped connections every time. As mentioned earlier, that means proper matching of the crimp terminal to the wire size, the correct type of wire (multi-stranded, not domestic building wire) and a half-decent crimping tool.

Before I learned this lesson I made a lot of bad joints in automotive applications! Contrary to a lot of earlier comments about corrosive resins etc., I believe the big killer is vibration.

When you solder (or even 'tin') a stranded copper wire, you lock the many strands (only 7 strands in 'poor' wire or maybe 28 or more in decent wire) into a stiff single strand. Whether that stiff 'strand' is now terminated into a crimp lug, a screw terminal or a battery lug, it now acts only as a thick, stiff single strand of copper. I've found that it's now not the termination that fails - it's back where the stiff soldered chunk of wire meets the stranded wire that fatigues and cracks, that the joint fails.

My two-bobs worth: use good quality automotive multi-strand wire, and join it using good quality crimp terminals and a really good crimp tool. A good crimp tool is like a good hacksaw frame or a good set of sockets - you'll get a lifetime of reliable service out of it.

Ian

I have been a licenced aircraft engineer for around 15yrs now and find it interesting to read that alot of the older RAAF fellas mention that teminals/connections are usually soldered on their aircraft.
Working on Boeing, Airbus, BAe, Foker and for a few year certifying bug smashers too, i have never seen- and i mean NEVER seen a soldered connection on aircraft from Cessna 152s to Boeing 747-400s.
Crimped connectors are used and there are a huge amount of different types, and an equally huge amount of crimping pliers to suit.
I use a blue-point ratcheting type double crimper for all of my connections and have never had a drama.
As mentioned, soldering is prone to a number of different problems which would be more common and harder to find than a simple crimped connector/terminal end.
If the problem associated with crimped connections is moisture and dirt causing corrosion, then why not wrap electrical tape over connections and as for eye end terminal ends, do as they do on aircraft which see conditions far more extreme that any 4wd would see... simply cover the eye end and bolt/screw with sealant. (Just dont use one which has an acidic cure).
Cheers!

Having worked at Holden in their engineering facility in the 90's after the electrical disasters such as the VK had been learned from you'll find that the majority if not all of the joints in vehicles from the late 80's onwards are all crimped.

Soldering creates a point susceptable to fatigue at the junction where the solder stops and the cable becomes coppers strands. Vibration - only a little is needed - eventually causes fatigue and broken strands. At the point where one strand breaks heat is a result of the increase in resistance if passing higher currents and promotes further fatigue.

Crimp connectors (quality ones) generally have two crimp points. One creates the electrical connection by compressing tightly the conductor. Compressing it properly with the right tool nearly completely melds the copper strands into an air free solid conductor reducing oxidisation. The second crimp point is usually over the insulation, or piercing the insulation without actually compressing it very much. This provides strain relief so that the point at which the compressed conductor becomes strands it doesn't vibrate and fatigue like the old solder joints.

Even the plastic sleeved red, blue & yellow crimps have strain relief built in if you use a good quality ratchet crimper - and the right size crimp for the wire & insulation. The crimp point close to the lug/spade/ring compresses the conductor into the crimp terminal. The crimp point closer to the cable squashes the plastic sleeve onto the insulation to prevent flex of the conductor joint.

If it's going into something that vibrates don't solder it. If it's going into an amplifier or some static piece of equipment either is fine.

As others have alluded to. If you don't know what you are doing don't do it.

I don't get my mechanic to do my tax, or my accountant to fix my car. I expect that if someone gets sick or hurt they call an ambulance not the RACV. Those that DIY stuff that they don't really know much about inevitably find themselves at the mercy of Murphy's Law at the least convenient moment. The $100 they may have saved on getting that widget system hooked up might well be spent later 10 fold if they have to be recovered from a remote location if it fails.

Dave

Dave