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Discussion Starter #1
Anyone on this forum has read at least one post that I have commented on, where I am talking about galvanic corrosion. This is the same process that lets any battery work. Two dissimilar metals, and an electrolyte in contact with both is all that is required.

The most common electrolyte is dirty water. an electrolyte by definition is a source of free electrons, and it can act as a carrier to transport the free electrons between the metals.

The size of the battery (galvanic cell) can be incredibly small. When you see pitting in a metal part, that is due to the corrosion between the constituents which make up the alloy. Steel and aluminum alloys are really a lattice which is trapping other materials within it. Not unlike multi grain bread...... just much tinier.

The chart I have attached describes how much reaction you can get between different types of alloys. The further apart the two are, the more quickly they will corrode.
 

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Discussion Starter #2
This is why it's generally a bad idea to polish frames and rims..... unless you immediately seal the polished surface, it will begin to corrode. Not saying it cannot be done, just saying that the increased maintenance is more bother than it is worth.
 

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Interesting to say the least. Thank you for sharing your knowledge with the rest of us.


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Sailors are intimately familiar with this.... salt spray is an ideal electrolyte.
 

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RJ always delivering the knowledge 👍. RJ, theres a dude on youtube whose channel is called SmarterEveryDay. I think u will really enjoy his videos.
 

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That whole left handed and dyslexic thing has kept me learning my whole life. Everything out there, is effectively in an adversarial role, for me. Reading is often a challenge, because so much of what people leave out of a conversation is 'common knowledge' --if you are right handed. That flows right into how things are arranged. door knobs, hallways, latches on nearly everything.... buttons on controls....arse backwards, I tell you!
 

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Corrosion is a real thing, however...........

Suggesting someone not polish their aluminum frame for fear of increased rate of corrosion? How is the frame going to corrode more? at the bolts? on the surface?

I see dozens of polished frames every season, most of these people did it themself and didn't put anything over it (clearcoat) and simply use some sort of polish or wax several times a year..... some of these bikes have had polished frames for decades--- I don't see any added corrosion or issues

in fact....... I see far more corrosion issues with the idiots who feel the need to wash their motorcycle everytime they ride (or some other accelerated rate of stupid) becasue they keep introducing more and more water into all the bolts and bushings

Perhaps there is some correlation between people who polish their frames and those same people may have a propensity to wash their bike more often, but I don't see that here with the customers bikes I see

Hell half my customers don't seem to wash their motorcycle ever, sadly......... always coming in full of bug guts and road grime...
 

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Discussion Starter #8
It's the nooks and crannies that trap water, where the worst of the effects occur. When the gaps are so small the water stays there in a film.... like the pages of a wet book. Bikes are designed by people who know that they will get wet, and the majority of things that are affected are quite well protected.... for some multiple of the warranty period, at least.

This is why flood damaged cars and bikes are considered a write off by most insurance companies. Nearly impossible to get all of the water out of every nook and cranny..... the labor to break it all down and then reassemble it is the bigger breaking point.
 

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An extreme example of this was the attempt by the Navy to recover and recondition components of an F-14 Tomcat that had left a runway at (then) NAS Alameda, and ended up in SF Bay, in '87 or '88.

I don't know how long the aircraft was submerged; my guess would be less than 72 hours. The article I found says it was in 12 feet of brackish water.

I worked with the guy in the corrosion control lab at (then) NAS Miramar to try and recover circuit boards, and black boxes so that they could be re-used in other aircraft.

Military aircraft circuit cards are all built to a much higher level of environmental protection, than anything sold to civilians. Rugged enough to survive 9 G turns, severe levels of shock and vibration, everything on the board is conformally coated in a lacquer or other material clear coat so that they are far more resistant to the effects of moisture and dust than typical commercial off the shelf electronics.

Dunked for a few days, then however long it took to get the parts to San Diego, and we started in trying to remove the salt and repair the circuit cards.

We did everything we could, from ultrasonic cleaners, to chemical conversion processes, to extreme drying, lots of solvents that would make a safety representative run away.... no matter how well we flushed, rinsed, washed, scrubbed.... there was always residual salt that could not be removed. The boards would look frosted within a day or two after every treatment we tried.100% loss.

Commercially produced high volume electronics are most definitely not built to that same standard, unless they have a specific requirement to do so. The ECU is an example of one approach to making electronics robust in the face of weather. Everything inside the enclosure is flooded with some sort of inert non conductive filler -- in the military that was called 'potting', and was done with everything from silicone RTV, to epoxy. Dumping heat is always an issue when you do that.... hence why the '05 ECU fries. Somebody cut the margin too thin.

The weak link is always the interconnections.

I quote Sir Stanley Hooker frequently when talking with engineers.. "The greatest impediment to progress, is the interface between disciplines." (He was knighted by the Queen of England, for saving Rolls Royce from going bankrupt as they tried to build the jet engines for the 747. Bragging rights between development teams nearly did that in.)

Any time there is a quick disconnect on a wiring harness, or a plug and receptacle, there is a change in the amount of contact. In order to make it so you can mate the male and female pins, you have to have mechanical clearance..... air gaps stop the (easy) flow of electricity. Switches, and connectors all use a very limited number of points of contact to make the connections that are needed. In the case of a connector, the male pin has a dimple on it that is left with a sharp edge. As it is slid into the female pin, it scratches away any preservative on the mating surface (or corrosion) and that allows a low resistance connection. Bare metal exposed to a damp environment..... corrosion inevitably occurs. It's simply a matter of how long it takes to corrode enough to cause a problem.

*always a good idea to disconnect the plugs on your wiring harness.... that scrapes off the corrosion, and puts the contacts back into direct connection on bare metal instead of oxidization. This is where the dielectric grease comes in. The contacts can push through it, but it flows around that point of connection and seals out air and water.

The kill switch is another example. If it is never moved, it will eventually fail because the dissimilar metals in the contacts will corrode and create a high resistance path. Same thing with the side stand and clutch switches. So long as they are used on a fairly regular basis, the 'make-break' will scrape away the corrosion. Add in dirt and water......

Relays, same thing..... the wiper from the common pin to the position it constantly sits on will eventually rust to the NC pin, or the rust will never let it make contact.
 

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An extreme example of this was the attempt by the Navy to recover and recondition components of an F-14 Tomcat that had left a runway at (then) NAS Alameda, and ended up in SF Bay, in '87 or '88.

I don't know how long the aircraft was submerged; my guess would be less than 72 hours. The article I found says it was in 12 feet of brackish water.

I worked with the guy in the corrosion control lab at (then) NAS Miramar to try and recover circuit boards, and black boxes so that they could be re-used in other aircraft.

Military aircraft circuit cards are all built to a much higher level of environmental protection, than anything sold to civilians. Rugged enough to survive 9 G turns, severe levels of shock and vibration, everything on the board is conformally coated in a lacquer or other material clear coat so that they are far more resistant to the effects of moisture and dust than typical commercial off the shelf electronics.

Dunked for a few days, then however long it took to get the parts to San Diego, and we started in trying to remove the salt and repair the circuit cards.

We did everything we could, from ultrasonic cleaners, to chemical conversion processes, to extreme drying, lots of solvents that would make a safety representative run away.... no matter how well we flushed, rinsed, washed, scrubbed.... there was always residual salt that could not be removed. The boards would look frosted within a day or two after every treatment we tried.100% loss.

Commercially produced high volume electronics are most definitely not built to that same standard, unless they have a specific requirement to do so. The ECU is an example of one approach to making electronics robust in the face of weather. Everything inside the enclosure is flooded with some sort of inert non conductive filler -- in the military that was called 'potting', and was done with everything from silicone RTV, to epoxy. Dumping heat is always an issue when you do that.... hence why the '05 ECU fries. Somebody cut the margin too thin.

The weak link is always the interconnections.

I quote Sir Stanley Hooker frequently when talking with engineers.. "The greatest impediment to progress, is the interface between disciplines." (He was knighted by the Queen of England, for saving Rolls Royce from going bankrupt as they tried to build the jet engines for the 747. Bragging rights between development teams nearly did that in.)

Any time there is a quick disconnect on a wiring harness, or a plug and receptacle, there is a change in the amount of contact. In order to make it so you can mate the male and female pins, you have to have mechanical clearance..... air gaps stop the (easy) flow of electricity. Switches, and connectors all use a very limited number of points of contact to make the connections that are needed. In the case of a connector, the male pin has a dimple on it that is left with a sharp edge. As it is slid into the female pin, it scratches away any preservative on the mating surface (or corrosion) and that allows a low resistance connection. Bare metal exposed to a damp environment..... corrosion inevitably occurs. It's simply a matter of how long it takes to corrode enough to cause a problem.

*always a good idea to disconnect the plugs on your wiring harness.... that scrapes off the corrosion, and puts the contacts back into direct connection on bare metal instead of oxidization. This is where the dielectric grease comes in. The contacts can push through it, but it flows around that point of connection and seals out air and water.

The kill switch is another example. If it is never moved, it will eventually fail because the dissimilar metals in the contacts will corrode and create a high resistance path. Same thing with the side stand and clutch switches. So long as they are used on a fairly regular basis, the 'make-break' will scrape away the corrosion. Add in dirt and water......

Relays, same thing..... the wiper from the common pin to the position it constantly sits on will eventually rust to the NC pin, or the rust will never let it make contact.
So heres a question for you. How often should someone disconnect and reconnect the electrical connections on our bikes for example? They’re rated for a certain amount of times you can disconnect and reconnect them correct? So how often should that be? When issues occur? Or should this be a basic maintenance item?


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Discussion Starter #15
I would expect that the connectors are designed for somewhere around 50 mate-demate cycles. If you treat a connection with dielectric grease, it will not corrode as quickly.
 
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