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I have noticed some stores and vehicle dealers selling a product to prevent rust the relies on inducing a current on the metal surfaces of the vehicle.
Can anyone explain how these work and if the are effective?
I'm familiar with catodic protection and sacraficial anodes but this is far beyond my grey cell capacity. [img]/forums/images/icons/grin.gif[/img]
Egon [img]/forums/images/icons/grin.gif[/img]
Black Magic - doesn't work. The concept is interesting but . . . .
Egon, haven't those things been around 50 years or so? I think I was a teenager the first time I heard of them. But I don't recall hearing anything good about them except from the folks selling them.
I've never heard of them till lately.
One Canada wide store is selling them and I also saw a marque car dealership offering them.
I was just hopeing some could tell me enough about the principal so I could ask questions. [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]
Egon [img]/forums/images/icons/grin.gif[/img]
It's called cathodic protection and it is the only sure method of preventing rust on a vehicle. It has been used in the underground pipeline industry for 50 years to keep pipe from rusting. You can also transfer it from one vehicle to another.
Cathodic protection is also used for underground tanks and other metal objects subject to moisture that acts as an electrolyte to promote corrosion (see also dissimilar metal corrosion.)
Egon, Perhaps the cathodic protection you are used to is the "passive" variety such as zincs on a prop shaft or propeller or as part of a bonding system connecting all the metal through hulls etc together and protecting them with a sacrificial electrode (zinc.). There are also "active" systems with reference electrodes and electronic circuits to detect and neutralize electrolytic currents. This is used on boats and metal structures subject to electrolytic action and the better systems are superior to the passive approach.
As far as the units sold for cars... I have no personal knowledge of them and as far as I know they could be snake oil or a terrific boon.. No experience or opinion.
Pat
I am familiar with the active protection systems. They are pretty common where I used to work. [img]/forums/images/icons/grin.gif[/img]
Egon [img]/forums/images/icons/grin.gif[/img]
The active systems you are familiar with are for in-ground or underwater metal, nicht var? I personally have no clue as to how you'd use them on above ground insulated from the earth (rubber tires) vehicles. How 'bout you, Egon?
Pat
Me, I get confused because one post of the battery is already connected to the body to complete one circuit. If this circuit does not work putting on another charge in the opposite direction kinda gets me all confused. Or is it something like a two way check valve on a pipeline??
Egon [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img] [ soon as I started grinnin I got similes ] [img]/forums/images/icons/grin.gif[/img]