Wiring joints - to solder or crimp or both?

Submitted: Sunday, Apr 09, 2006 at 17:47
ThreadID: 32710 Views:4910 Replies:15 FollowUps:4
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With all of the wiring talk going on, I have a question.

An old auto eletrician mate of mine says to always solder and crimp any joints. Other people have said that solder potentially hardens the copper and therefore weakens a joint which can lead to failure in the tough 4WD environment.

What do other people think?

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Reply By: Derek from Affordable Batteries & Radiators - Sunday, Apr 09, 2006 at 17:55

Sunday, Apr 09, 2006 at 17:55
Solder and crimp.

Use a good quality wire and a hot iron or gas tool. Don't let the solder run up the wire to cause hardening .

Plain crimping allows corrosion and voltage drop.

Regards Derek.
AnswerID: 165978

Follow Up By: datto311 - Sunday, Apr 09, 2006 at 18:15

Sunday, Apr 09, 2006 at 18:15
Ahhh That's been my problem I get the solder running up the wire. Last time, I tries this, I used my partner's lead-lighting electric iron and that worked much better.

You're right about crimping. I have a problem on my sports car with some connectors I put on years ago where the wire is now pulling out and it is all green
FollowupID: 420905

Reply By: Member - Mike DID - Sunday, Apr 09, 2006 at 19:09

Sunday, Apr 09, 2006 at 19:09
One thing to avoid is tinning or soldering a wire and then crimpimg it or putting it into a screw terminal.

The solder cold-flows and you eventually lose contact pressure.

AnswerID: 165991

Reply By: johannagoanna - Sunday, Apr 09, 2006 at 19:17

Sunday, Apr 09, 2006 at 19:17
Solders and then put those little heat shrink plastic sleeves over the top! Works every time, and hasn't let us down yet! - Jo
AnswerID: 165996

Reply By: Keith_A (Qld) - Sunday, Apr 09, 2006 at 19:27

Sunday, Apr 09, 2006 at 19:27
A very good question Noel, and one that has crossed by mind (or whats left of it).
Here are some comments from the NET -

A crimped connection is totally dependent on the tightness of the crimp and nothing loosening up. Crimps should be done with a good ratcheting crimper with
the right die for the crip.

...I emphasize the word good - because a 'cold' solder joint is a guaranteed problem. Have enough heat so that the solder easily flows into the joint.

ABYC does not recommend solder because the wire becomes stiff and is prone to failure due to vibration. Capillary action can indeed draw solder quite a distance up the stranding of the wire and turn it into solid wire, which is a no-no in any stressed environment. Yes you can "support" it, but what does that mean - the support would have to consist of something that would prevent the stranded part of the wire from flexing at the point where it becomes "solid" due to entrained solder. A crimped connection is still flexable.

A properly crimped connection will NOT be flexible in the area of electrical contact. The wire within the crimp should form a "gas tight" seal between the strands and the connector.

Any type of crimp connection to a wire end should be crimped using the correct tool. It should make (as others have mentioned) a gas-tight connection between wires and crimp connector.
What you definitely should not do is solder the end before crimping the connection or solder the wire-end and screw this into any terminal or strip. This is a big no no, as this type of connection will come loose rather quickly.

Damn - made a few mistakes myself it seems! And my Supercheap crimper may not be quite up to the job.
I have also been guilty of cooling solder joints too quickly, which causes increased resistance in the joint . Live and learn.......
AnswerID: 166001

Reply By: Member - Nick (Kununurra) - Sunday, Apr 09, 2006 at 19:51

Sunday, Apr 09, 2006 at 19:51
What about neutralizing the acid in acid core solder,we always spray crc or the like on joints just soldered,have seen many joints eaten away from its own acid.
AnswerID: 166009

Follow Up By: Bob Y. - Qld - Sunday, Apr 09, 2006 at 20:57

Sunday, Apr 09, 2006 at 20:57
Always best to use resin cored sloder, Nick. No worries about the acid effect then.

How's the 100 going now, with recon pump?

Seen it all, Done it all.
Can't remember most of it.

Lifetime Member
My Profile  My Blog  My Position  Send Message

FollowupID: 420959

Follow Up By: Member - Mike DID - Sunday, Apr 09, 2006 at 22:35

Sunday, Apr 09, 2006 at 22:35
Acid core solder is great for plumbing - NEVER use it for electrical work.

FollowupID: 420992

Follow Up By: Member - Nick (Kununurra) - Monday, Apr 10, 2006 at 20:10

Monday, Apr 10, 2006 at 20:10
Gday Bob,the old cruiser is going great(no thanks to Toyota) mind you after waiting 5 weeks it would wanna be.
FollowupID: 421134

Reply By: roger baker - Sunday, Apr 09, 2006 at 22:25

Sunday, Apr 09, 2006 at 22:25
Hi Guys
Crimp type electrical connections are good if the following conditions are met
1 Correct cable
2 Correct terminal
3 Correct pliers
and a good test is after crimping place the terminal in a vise and give the cable a good yank. If it separates it fails.
Crimping is supposed to produce a "cold weld" and, if done properly is OK.
I usually Solder my connections because it is often difficult to match all 3 criteria.
Use resin cored solder and a hot iron feeding the solder from the terminal end of the connector and stop when the solder appears at the cable end of the terminal

AnswerID: 166069

Reply By: geocacher (djcache) - Monday, Apr 10, 2006 at 05:31

Monday, Apr 10, 2006 at 05:31
The automotive industry left soldered joints years ago due to the problems they created - crimping if done properly is faster and more reliable.

I spent many years in the Instrumentation workshop at GMH Engineering as a technician, it is based on that experience that I make the following observation on joints in the automotive setting.

I've seen many more soldered joints fail than crimped joints. To highlight the susceptability of solder joints failing consider that even solder joints on circuit boards which have been subject to little vibration and/or significant mechanical stress still fail due to less than optimal preparation of surfaces or oxidisation of surfaces prior to the joint being made.

In almost all cases where the solder joint in a wire to wire connection failed it was due to either poor joint quality by an inexperienced person, or mechanical fatigue at the solid/flexible. Often the former is caused when trying to solder old cable to new cable. Once oxidisation has started within the cable it is hard to get a good joint. Often the older cable can't easily be replaced but a crimp joint will provide a much more reliable connection in the long term in this situation.

In the cases where the crimp joints have failed it is usually wrong crimp size (common) or poor tool used to set the crimp.

The ratcheting crimp tools for the red/blue/yellow automotive type crimps used to be well over $100 when first released but thanks to design piracy can now be bought for under $50 - which is far less than the the $ value of a few hours inconvenience due to a failed crimp in the field.

If you have to put a wire into a screw terminal consider using the crimps that provide a flat tag to screw onto and crimp the wire joint.

Buy a good crimper, keep a good range of crimps and use the right crimp size for the cable.

Crimps are definately the way to go.


AnswerID: 166083

Reply By: Philip A - Monday, Apr 10, 2006 at 08:44

Monday, Apr 10, 2006 at 08:44
I only use non insulated crimps which are really hard to get but worth it.

I bought a ratchet crimper from Jaycar with the correct dies for about $50 if I recall.
I bought a large volume of non insulated crimps from the USA at a reasonable price. These were joiners, and male and female blades in different wire sizes.

Before you crimp, you should slip some correct size heat shrink tube over the wire and heat it over the joint, about 15MM each side.
Never had a problem and do not expect to as these joins are OEM quality.

For large crimps go to your friendly auto electrician .

I once lost an alternator from a bad solder joint on the output. Heated up, melted all the diode/board solder, and the field wires caught the armature.
One learns from experience.
Regards Philip A

AnswerID: 166105

Reply By: Shaker - Monday, Apr 10, 2006 at 09:07

Monday, Apr 10, 2006 at 09:07
I can't see why crimping wouldn't be OK, it is usual in the marine industry!
If you are worried about cable turning green, use tinned cable.
AnswerID: 166107

Reply By: Member - Mike DID - Monday, Apr 10, 2006 at 10:14

Monday, Apr 10, 2006 at 10:14
Improperly done solder joints fail.

Improperly done crimps fail.

Which is the best for YOU to use, seems to depend on which one you have the tools and skills and to do properly.
AnswerID: 166118

Reply By: Member - ROTORD - Monday, Apr 10, 2006 at 10:57

Monday, Apr 10, 2006 at 10:57
Hello All

NASA lost a number of space shots and sattelites to electrical problems which they determined were caused by bad soldering . Their answer was to design a High Reliability Hand Soldering course for tecnicians . The RAAF followed that lead , and the RAAF HRHS courses , run in Field Training Centres , were a full working week in length . The courses were very well received , and the general attitude was that if you did the course you could solder , and those who hadn't done the course didn't know the complexities of the problem .

I suspect that , with quality equipment , it would be easier to produce a good join with crimping than by solder .
AnswerID: 166127

Reply By: Michael Carey - Monday, Apr 10, 2006 at 18:25

Monday, Apr 10, 2006 at 18:25
Nothing beats a properly crimped terminal. Virtually all terminals in a modern car are crimped.....
#1 Quick and easy to do.
#2 Reliable.

I only solder connections designed to be soldered.
Crimp terminals are designed to be crimped. If the wire is loose then you either have the wrong terminal for the wire size you are using OR you have crimped it incorrectly....

AnswerID: 166213

Reply By: Member - Robert G (WA) - Tuesday, Apr 11, 2006 at 11:54

Tuesday, Apr 11, 2006 at 11:54
After continually dealing with corroded wire joints (soldered and crimped ones) in an old boat I had, I went to a marine chandler and now use their specialised gear for wiring works. Tinned wire is great but it is expensive, so be prudent where you use it unless money is no object. There are heaps of connectors and crimps with silicone and grease type sealants built in which when used with a quality pait of crimps, are about as good as it can get imo.
AnswerID: 166420

Reply By: Kiwi Kia - Tuesday, Apr 11, 2006 at 15:11

Tuesday, Apr 11, 2006 at 15:11
If the wire is likely to move or subject to vibration then DO NOT SOLDER.

There is nothing wrong with crimp joins just use quality lugs (tube like - not split down the side and folded over).

In the electrical industry you are not allowed to solder most joints anymore. There are a few exceptions like on door bell type voltage etc.
AnswerID: 166453

Reply By: datto311 - Tuesday, Apr 11, 2006 at 16:35

Tuesday, Apr 11, 2006 at 16:35
Thanks everybody

The consensus seems to be use good qualilty connectors and a good quality crimping tool. Time to throw away my cheapie crimping tool ! Time to start using quality connectors as well

AnswerID: 166467

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