Corrosion inhibitors inside a crimp connection? Seems like a bad idea

[willprowse]

Hey guys!

I am seeing some disagreement among electrical engineers on what is best:

Option 1: Perform a crimp connection termination with a small bit of dielectric grease or corrosion inhibitor, then use heat shrink over the joint.

Option 2: Perform a crimp connection termination ensuring that the wire and the connector are clean, dry and free from grease or anything else. Then use a high quality heat shrink with adhesive to protect the joint. 

When I learned about cold welding, I learned that the two surfaces need to be as dry and clean as physically possible. If they are clean, and you create a true termination, the joint should be a gas tight joint.

What use is having a corrosion inhibitor in a joint that is gas tight? I fail to see the reasoning there. I love using corrosion inhibitor on joints that need to be removed, such as car battery terminal or specific marine applications, but fail to see why it would be used inside the actual crimp joint. 

A problem that I have also read is that using dielectric grease/corrosion inhibitor in a joint is that some of it will get pushed out during the termination process. Having any reside on the joint will cause the heatshrink to not adhere to the joint how it should. This is not good. 

What do you guys think? I have been doing terminations dry and with heatshrink for ages, and never had corrosion inside the termination. I dont see how that could possibly happen if a cold weld mated the two surfaces. 

If I am completely wrong, let me know! I am getting a mixed bag of answers online and from friends in the industry, so I am unsure of what to believe at this point. I am using only my knowledge of cold welding to draw conclusions.

 

[John61CT]

Yes, a proper gas-tight crimp will not get corrosion inside the connection, only on outside surfaces.

But if talking about the join between two terminators like a spade connector M/F or Andersons etc, then I could see it more.

That said, lots of people I respect do use "contact preserver" stuff like Dow Corning #4, Noalox, Boeing T-9.

Also Oxgard, Caulgel, Fluid Film, Lanocote, Boeshield.

And it seems very common in aircraft, which have very stringent requirements.

So, like the old solder vs crimp, experts do disagree.

 

[Ticklebellly]

I cannot generate any rationale for including a corrosion inhibitor in a pressure welding environment. A crimp connection is intended to create a "voidless mass"; any foreign matter would only get in the way.

MIL-Spec crimp instructions do not include any anti corrosion treatment. Most MIL-Spec connectors are wholly contained in conformal seals to exclude the environment. I suggest clean materials crimped with the right size crimper and then protected with heat shrink is the right way to go.

 

[Trebor English]

Inside the joint where the two conductors are actually contacting there is no oxygen or other gas and no corroding will happen.  Outside that tiny universe there are chemicals like oxygen and water.  Between the outside and the inside there is a boundary.  As corrosion outside happens the boundary moves in.  Eventually, in theory, nothing happens since there are no chemicals inside and there is no motion or vibration.  

What I do is stick the end of the wire into the tube of OxGard, twist the strands again to work the OxGard between the conductors, then crimp.  In theory the grease is excluded from the gas tight joint due to the force of the crimping.  The boundary between the gas tight joint area and the outside world is greased protecting that boundary, not the interior of the joint.  

Back to the original question:
"What use is having a corrosion inhibitor in a joint that is gas tight?"  None.  Inside the joint, none.  Outside, protecting the boundary, none if there is no condensation or fumes or oxygen or anything reactive.

 

[Doubleone]

I know there will be someone who'll swear crimp works for them, or military uses it, etc.  I'm just sharing what I know and what works for me.  I've built racecars and off-road trucks that operate in an extreme high vibration environments.  Even the tiny electrical components inside the radios require prep to prevent vibration fatigue.  I've seen nothing but failures with crimping, either mechanical separation or corrosion and resistance, so understandably I'm not a fan of crimp style connectors with or without heatshrink.  I crimp, solder, and heatshrink everything.  Zero corrosion, zero maintenance, zero failures.

 

[skyl4rk]

In the boatbuilding industry, greased butt joints are used to try to delay corrosion in a humid, salty environment. On land, and in the desert, just use dry butt joints.

 

[tx2sturgis]

.... I'm not a fan of crimp style connectors with or without heatshrink.  I crimp, solder, and heatshrink everything.  Zero corrosion, zero maintenance, zero failures.

I could have written this....exactly the way I do it.

Crimp, solder, heatshrink, on large connectors especially. 

Then anti-corrosion treatment applied to the subsequent mechanical connection, such as a ring terminal attached to a threaded stud and nut.

 

[John61CT]

Inside the joint where the two conductors are actually contacting there is no oxygen or other gas and no corroding will happen.  Outside that tiny universe there are chemicals like oxygen and water.  Between the outside and the inside there is a boundary.  As corrosion outside happens the boundary moves in.  Eventually, in theory, nothing happens since there are no chemicals inside and there is no motion or vibration.  

…
"What use is having a corrosion inhibitor in a joint that is gas tight?"  None.  Inside the joint, none.  Outside, protecting the boundary, none if there is no condensation or fumes or oxygen or anything reactive.

Excellent, 100% agree, well stated.

Great references, whole site worth digging through for electrickery topics

https://marinehowto.com/making-your-own-battery-cables/

https://marinehowto.com/marine-wire-termination/

https://marinehowto.com/solder-and-poor-trouble-shooting/

 

[Ticklebellly]

Wanna talk high vibration environments? Two generators hang off the Combining Gearbox on Chinook helicopters. All the connecting wires to the generators end in crimped connectors bolted down to terminal blocks.

Back in the late 70s, I used to teach the NASA developed hand soldering course to people building and repairing aircraft components. Avionics technology has moved on now. Totally impracticable to try to solder a 200 pin Cannon plug on aircraft wiring looms. Properly done crimps in designed vibration relief, do not fail.

MC4 connectors can be crimped or soldered and the water proofing (I forget the IP rating) incorporates strain and vibration relief. As has been said above, if the environment cannot access the joint, soldered or crimped, corrosion just does not happen.

 

[Weight]

A properly made crimp with a quality lug and heat shrink doesn't need grease. Key words; properly made & quality. Di-electric grease is non conductive. There are greases that are conductive and are used on aluminum wire. We do not use aluminum wire! I have seen many soldered connections fail. I have not seen any proper crimps fail. Artillery Track Vehicle Maintenance Specialist E8, retired.

 

[Trebor English]

We do not use aluminum wire!  

Sometimes people buy wire using the internet and get copper clad aluminum and don't understand what they got.

 

[Weight]

Yes Trebor. That is why I recommend Genuine Dealz dot com. Bay Marine Supply are also good, located on the west coast. Most of the cheap jumper cables sold are aluminum wire.

 

[Manyways2go]

Failures and repairs required in high vibration areas usually result from a rushed poor installation. Then it can be difficult to locate and take hours to diagnose if not very obvious. I have crimped soldered and used heat shrink but the best results are a product of better tools and materials. I have experience with cannon plugs and other weather type connector each require specialized tools and connectors. I would think not available on the shelf locally. Lead acid battery connections seem to be there worst problem area requiring high maintenance due too gaseous conditions. In our mobile environments a heavy crimp-er tool soldered or not with good heat shrink seal then secured against vibration would be good.
Additional products dielectric grease etc. might help protect if you think moisture is an issue, I do not see it used much all the time but was factory install on vehicles in some connectors on some vehicles so their engineer saw it preventative. Now if I'll only do my own properly that would be good. Just my two cents

 

[John61CT]

http://genuinedealz.com is yes great for custom lengths, optionally already well terminated for you (measure twice!) Only $1 per crimp!

The good stuff wire spec if setting up to DIY is

UL1426 105c tinned type 3 "boat cable" 

but lots of counterfeiting of all this stuff going through Amazon markets, eBay etc,

Known-good marine supply houses are best to avoid that.

Ancor is the best known quality maker, thus usually overpriced try fisheries supply.

Pacer is just as good, available here http://www.bestboatwire.com , genuinedealz' sister company

EPM (Deka batts) makes good stuff, also Berkshire Wire in Western MA, call for nearby distribution.

Avoid Cobra

You also need to be picky to get quality termination supplies, FTZ and Ancor are great

The right crimpers are expensive! Maybe see if you can find them to borrow (West Marine, local marina / boatyard) or rent, then buy the fittings to match the crimpers available that way.

 

[bigskybob]

Just forget the crimping thing and use a wirenut with alox.then seal the wirenut with silicone.No more problems.

 

[Weight]

No End to problems if using wire nuts.

 

[highdesertranger]

please everyone don't use wire nuts in a mobile application. highdesertranger

 

[Redbearded]

I found these which seems like a good solution for butt connectors at least. It has low temp solder and seals watertight for connections. No need for grease at that point.

 

[John61CT]

If you really want to do it right, crimp as above, copper gets fused into a gas-tight solid block, can verify with a milspec pull test.

There are dozens of ways to do it, in many cases easier and of course cheaper, and for some owners, "good enough".

But doing it **right**, not so many ways.

 

[maki2]

Yes, a proper gas-tight crimp will not get corrosion inside the connection, only on outside surfaces.

But if talking about the join between two terminators like a spade connector M/F or Andersons etc, then I could see it more.

That said, lots of people I respect do use "contact preserver" stuff like Dow Corning #4, Noalox, Boeing T-9.

Also Oxgard, Caulgel, Fluid Film, Lanocote, Boeshield.

And it seems very common in aircraft, which have very stringent requirements.

So, like the old solder vs crimp, experts do disagree.

I worked for more than 15 years at Boeing in final assembly, in the wire shop, and in  sub assembly fabrications shops. They never use any corrosion preventative inside of crimped wire connectors. I do not know where you got the idea that it is common to do so in aircraft. I also took courses for aircraft and powerplant certification and worked at two other aircraft companies. I can assure you that Boeshield T-9 is not used inside of or on the outside of any electrical connections on airplanes nor is any other chemical product used.

When we needed to attach a wire to structure using some type of ring terminal on the end at no time did we ever apply any type of corrosion inhibitor. Instead a small piloted wire (bonding) brush was used to scrub clean the metal surface to create a true bare metal surface where the terminal was being attached. The surface was also cleaned with acetone to remove any contamination such as oils or other chemicals before the terminal was attached to the structure. That is a specific process called bonding and you have to go through certification and yearly recertification courses to qualify to do it. Your name is part of the FAA record of exactly who did the bonding on which parts on each specific airplane. If you are not trained and certified you can't do that job. I was trained and certified for that work.

You don't see chemicals being applied to wire terminations in the automotive industry either.

As to the corrosion inhibiting chemicals interfering with heat shrink. There are several types of crimp on terminals, one is made to be waterproof, it certainly would not bond properly if there were any petrochemical corrosion inhibitors applied to the wire.  If you want waterproof terminal connections then buy the products made specifically for that purpose.

Rule # 1 on watching youtube videos, don't believe that everything you see people do in them is how professionals do that type of work. Of course the same thing goes for what you read in forums.  So how do you know I worked at Boeing?  The photo below is from their in-house newspaper, it was taken in 1981, that is me when I was working on a mockup project for an extended 737, installing some brackets to hold hydraulic lines. Mockups were used to test fit everything before they switched to testing it all in 3D CAD. Sorry no photos of when I was working in the wire shop where I put on thousands of crimps. I spent time there when I needed a sit down job while recovering from back surgery. Very boring work but it certainly has proved very useful to know how to do it properly. Attaching terminated wire ends to structure is something I had to do in final assembly work and in sub assembly work as well such as building up the electrical equipment racks used below deck. Or attaching ground wires in various locations in the interior.