Soldering instead of crimping

I get it that crimps seem to be the better choice but it brings up the question of what is a proper crimp tool. Some of the cheap stuff I see does not look like it will do that good of a job. I'm guessing that on most crimping tools you need a nib that pushes down both sides at the crimp split, not just mashing everything.

A few years ago, I posed the solder vs. crimp question to a product developement engineer for one of the larger suppliers of marine electrical wire, terminals and accessories. This is what he stated.

When properly crimped, tinned copper wire and properly sized tinned terminals do not require soldering. The crimping force generates enough pressure to fuse the tin on the wire to the tin on the terminal providing a near zero resistance to current flow.

The down side to soldering as well as crimping is that the copper in the wire as well as the terminal becomes brittle and subject to fatigue breakage. Copper is somewhat unique as a metal when it comes to heat treating. When steel is heated and allowed to cool slowly it becomes more maleable (softer) and flexible. Copper on the other hand becomes harder and more brittle when heated and allowed to cool slowly.

He did suggest however that high amperage terminals such as battery cable lugs be properly crimped as well as soldered. His reasoning was that if there is heat generated by the high amperage at the terminal, it could break the electrical bond of the thin tin plating and cause some resistance. Resistance causes more heat and that increases the resistance even more etc. etc. His reccomendation was that terminals 8 gauge and larger (6,4,2 ect.) be properly crimped and then soldered. The fatigue factor due to the tempering of the copper is not as large a factor due to the strength of the larger wire.

If soldering is to be done, only resin core solder is to be used, never acid core or soldering paste. As well, the solder should be 50/50 (lead/tin) or better. The newer solders have replaced the lead with other metals (antimony?).

Lastly, he emphasized that the connection, especially in the marine enviroment, must be sealed to prevent corrosion from water and humidity. Adhesive lined heat shrink is highly recomended as well as anti-corrosion spray or grease.

We have been using the above proceedures for many years in commercial boats used in extreme salt water enviroments. None of our connections have failed at the wire/terminal connection.

I got help wiring my diy van from an industrial electrician friend.

He flatly refused to allow me to solder anything. Crimps are better with vibration and in any kind of short situation.

MotorPro wrote:
Simpe answer--either one done correcty will last---either one done poorly will not last

Crimp actually outlasts solder due to the fatigue issues I mentioned. Look in a rocket ship, satellite, or airplane and you will see crimps. Solder can only be used with appropriate strain relief to avoid the stress concentration next to the solder joint....then and only then will it compare to a (good) crimp for fatigue life.

I installed all the wiring my race car and used both crimp and solder. I had rain on the connections while trailering on the road along with massive vibration on the connections. For small wiring I used crimp only but always used shrink sleeve and supported the connection with two inches. On larger connections I crimped and soldered then used shrink sleeve and supported within two inches. 14 years on the car and never had an electrical issue. It takes more time to shrink sleeve each connection but that seals out moisture and adds some support to the joint. I have also used paint on electrical goo which turns solid in the open air. it works but I don't believe it holds up as well as shrink sleeve. I soldered on the larger connections as I was worried about losing some electrical transfer but I never actually saw any need for it.

For small wires, I pretty much solder everything, then use shrink wrap or silicone tape to insulate it.

For larger gauge wires that I installed in my solar system, between the inverter, solar controller, and battery, I bought quality heavy duty lugs (got high quality ones at the electrical depot dot com), and used a Hobart crimper. I pushed Ox Gard Anti-Oxidant grease into the wire before putting in the lugs, crimp them really good, then used adhesive infused shrink wrap. These connections all seem to be holding very very well, and I would definitely do large wire lugs the same way.

Simpe answer--either one done correcty will last---either one done poorly will not last

Dakzuki wrote:

gcloss wrote:
Soldering is always preferred over just crimping.

Not true. One must be very careful soldering as wire can fatigue and fail right next to the rigid solder joint. This is especially true in higher vibration environments.

In aerospace virtually all joints are crimped. The difference is the terminals are good quality (as are the crimping tools). Both can be had by the consumer (I have them) and it doesn't cost much more to do it right. Finding good wire is more problematic.

A crimper that looks like this is what you want.

This is what you want to avoid...both the el cheapo terminals AND the crimper.

x2. and RV's do see vibration.

My preferred crimper for smaller connector is this Sargent unit with interchangeable crimp dies.

Sargent crimp tool

da.bees wrote:
I have a Schumacher charger that I thought was going bad because charge rate jumps up and down. Noticed a spark from postive clamp handle and on closer inspection,the cripmed connection is bad. No corosion,no broken wires and no crack in crimp but gentely moving the handle or wire causes continuity to come and go. Who should know crimping technique better than Schumacher? I say crimp it then solder it. I believe corosion at soldered joints are the result of wrong flux,filler and/or failure to clean flux residue from completed joint.

I say buy a better charger that was crimped properly. Consumer goods (especially Chinese) are not a good example of manufacturing to last.

gcloss wrote:
Soldering is always preferred over just crimping.

Not true. One must be very careful soldering as wire can fatigue and fail right next to the rigid solder joint. This is especially true in higher vibration environments.

In aerospace virtually all joints are crimped. The difference is the terminals are good quality (as are the crimping tools). Both can be had by the consumer (I have them) and it doesn't cost much more to do it right. Finding good wire is more problematic.

A crimper that looks like this is what you want.

This is what you want to avoid...both the el cheapo terminals AND the crimper.