How worried should I be about the Home Depot technique for crimping stainless wire?

[Tomek]

It sounds like a funny story, but the load seems to be so light that I probably wouldn't worry about it! I'd guess that you would notice some loosening or cracks in the swage before an outright failure.

Based on a previous thread, a better alternative would be zinc-coated copper swages (aluminum/stainless steel is a corrosive match) crimped with an actual crimping tool. The crimping tool would be far more expensive than the project, though. I'm sure the Home Depot guy didn't have one to work with. If you could locate a crimping tool, I'd try again.

Actually, aluminum would work as a sacrificial anode, similarly to how zincs or magnesium pucks work. So the stainless wire will be somewhat protected from corrosion. I am not sure how the copper swages would behave especially zinc coated ones, but copper itself may promote corrosion of steel, even stainless. Stainless steel resistance to corrosion depends on its passivation layer - once it is destroyed it may start corroding, and corrosion products (iron rust) further catalyze the corrosion.
Having said that, you can expect aluminum to corrode, especially in salty water. It is not something generally expected but aluminum does corrode. Wrapping it with the rigging or other tape may trap moisture/water/salt inside actually accelerating the corrosion.

As for hammer crimping method, I would be worried if the swages developed cracks that may weaken them. Proper crimping should ensure that aluminum is pressed rather than hammered to avoid excessive local stress.

 

[rgranger]

Actually, aluminum would work as a sacrificial anode,

True but why would you want that? And it is stainless so no real need.

 

[Scott T-Bird]

These fittings aren't in the water ... why would cathodic protection need to be considered? Besides, it sounds like this is temporary until it is replaced with dyneema rope. There is no need to over-think this simple and light-duty application.

 

[Tomek]

These fittings aren't in the water ...

They will get splashed sooner or later.

 

[capta]

With a crimping tool and good quality crimp fittings so inexpensive these days, I'd do the job myself, as I have many times.

 

[MikeHoncho]

That's not a crimp. Its a smash.

 

[Davidasailor26]

They will get splashed sooner or later.

Yes, but for a sacrificial anode to work it needs to be in both electrical contact with the protected material and be in a common electrolyte. So the aluminum only protects the portion of the stainless that its actually sharing salt water with. The stainless doesn’t need any protection in the first place either.

I guess if the fitting does get splashed you could say the aluminum will corrode before the stainless. Unfortunately that’s not really a benefit if the fitting corrodes and drops the crimped cable.

 

[jssailem]

David, the corrosion for this type of gear is different than that of your prop and shaft. Your zinc’s on the shaft are not involved.

This the a similar system in that involves water and metal. Yet it is often slower. With stainless wire (specifically the lower grade stainless) is vulnerable to pit corrosion when water sits on the metal depleting the oxygen from the metal surface. This can rust the stainless from the inside out. A classic example is the rust that occurs on plastic covered wire lifelines.

I’m am reminded that it is “stainless steel “ not “stain free” or “never stain” steel.