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In theory, they are supposed to work by counteracting the chemical process that is rust by inducing a counter charge and/or act as an anode. Think galvanic corrosion. Two dissimilar metals/ an electrical charge will corrode the least noble metal. For example, Zinc will corrode before Iron. Aluminum will also corrode(oxidize) before iron. FEO3 is the chemical formula for rust and this all take place on the atomic level by way of electrons. A cast iron block with aluminum heads will create a charge in the coolant as the coolant ages(the coolant is an electrolyte in this scenario). This charge will cause the aluminum to corrode. Just a little metallurgy background here :).
In practice, most if not all electronic rust protection does not work. I’ve actually seen those things accelerate rust rather than prevent it.
I’ve been seeing less of these over the last few years, although they were never common. The end result is that no car I’ve seen equipped with one of these was by any definition, free of rust. Some of the cars have been less rusty that a usual example of the a similar car at that age/mileage, but people who bother to put these on their cars tend to take better care of them in general. Keeping a car clean (underbody and suspension especially) and trying not to drive thru puddles, mud, and road debris is the basic plan for keeping corrosion at bay. Cars with these devices in them, that look better than average, seem to be taken care of better than average as well and makes a huge difference. I haven’t seen one car with it that was miraculously free of corrosion.
[quote=”Fopeano” post=138375]I’ve been seeing less of these over the last few years, although they were never common. The end result is that no car I’ve seen equipped with one of these was by any definition, free of rust. Some of the cars have been less rusty that a usual example of the a similar car at that age/mileage, but people who bother to put these on their cars tend to take better care of them in general. Keeping a car clean (underbody and suspension especially) and trying not to drive thru puddles, mud, and road debris is the basic plan for keeping corrosion at bay. Cars with these devices in them, that look better than average, seem to be taken care of better than average as well and makes a huge difference. I haven’t seen one car with it that was miraculously free of corrosion.[/quote] ^This. The only way to be corrosion free is to move to the southwest(Arizona, NM etc) and buy a corrosion free vehicle there. Rust never sleeps and everything eventually turns to dust. Humidity and heat speed up the rusting process greatly, as does road salt. No device can hold up to either of those environmental factors.
I am with chevyman21 it accelerates rust. It is supposed to create this protective electrical charge. The only problem is most people never thing about how molecules bond together it is via electrons or protons in most cases. Any electrical charge positive or negative will attract electrons. Negative attracting other molecules which will then attract other molecules and so on and so forth. If anything the car frame is already grounded so in theory it is already in a negative state which would be the most ambitious of the two states to prevent rust. The best would be neutral but, that would require a hell of a lot more wiring increasing price and fuel consumption not to mention decreasing reliability.
All and all it is bs and not even advertised that well. Not to mention sending any kind of charge not setup normally in the car is bound to mess with thebattery if not sensors.
[quote=”MDK22″ post=138520]I am with chevyman21 it accelerates rust. It is supposed to create this protective electrical charge. The only problem is most people never thing about how molecules bond together it is via electrons or protons in most cases. Any electrical charge positive or negative will attract electrons. Negative attracting other molecules which will then attract other molecules and so on and so forth. If anything the car frame is already grounded so in theory it is already in a negative state which would be the most ambitious of the two states to prevent rust. The best would be neutral but, that would require a hell of a lot more wiring increasing price and fuel consumption not to mention decreasing reliability.
All and all it is bs and not even advertised that well. Not to mention sending any kind of charge not setup normally in the car is bound to mess with thebattery if not sensors.[/quote] Exactly. One needs to know at least basic chemistry to even have a chance at making an effective solution. When Iron corrodes as a base element it goes from FE to FEO2/FEO3. The O2 and O3 indicates oxygen atoms bonding with the iron. The atomic weight and electron count of iron is much higher than that of oxygen so the bond is very unstable and the iron begins to deteriorate. The only way to truly stabilize is to convert it to FE04….black rust.
PS: Steel is an iron alloy and therefore is impure iron. The more impurities iron has in it, the faster it corrodes as well. High Carbon steel will corrode faster than mild steel as well due to being even more impure. Chromium, Nickel and Lead are other alloying elements that resist corrosion. Have you ever wondered why stainless steel has such excellent corrosion resistance and sheen? Chromium is the answer or as the kids call it “Chrome”.
[quote=”Chevyman21″ post=138552][quote=”MDK22″ post=138520]I am with chevyman21 it accelerates rust. It is supposed to create this protective electrical charge. The only problem is most people never thing about how molecules bond together it is via electrons or protons in most cases. Any electrical charge positive or negative will attract electrons. Negative attracting other molecules which will then attract other molecules and so on and so forth. If anything the car frame is already grounded so in theory it is already in a negative state which would be the most ambitious of the two states to prevent rust. The best would be neutral but, that would require a hell of a lot more wiring increasing price and fuel consumption not to mention decreasing reliability.
All and all it is bs and not even advertised that well. Not to mention sending any kind of charge not setup normally in the car is bound to mess with thebattery if not sensors.[/quote] Exactly. One needs to know at least basic chemistry to even have a chance at making an effective solution. When Iron corrodes as a base element it goes from FE to FEO2/FEO3. The O2 and O3 indicates oxygen atoms bonding with the iron. The atomic weight and electron count of iron is much higher than that of oxygen so the bond is very unstable and the iron begins to deteriorate. The only way to truly stabilize is to convert it to FE04….black rust.
PS: Steel is an iron alloy and therefore is impure iron. The more impurities iron has in it, the faster it corrodes as well. High Carbon steel will corrode faster than mild steel as well due to being even more impure. Chromium, Nickel and Lead are other alloying elements that resist corrosion. Have you ever wondered why stainless steel has such excellent corrosion resistance and sheen? Chromium is the answer or as the kids call it “Chrome”.[/quote]
Never seen a rusty DeLorean 🙂 or 1999/2000 Volvo V70 XC.
[quote=”GearheadTool” post=138563][quote=”Chevyman21″ post=138552][quote=”MDK22″ post=138520]I am with chevyman21 it accelerates rust. It is supposed to create this protective electrical charge. The only problem is most people never thing about how molecules bond together it is via electrons or protons in most cases. Any electrical charge positive or negative will attract electrons. Negative attracting other molecules which will then attract other molecules and so on and so forth. If anything the car frame is already grounded so in theory it is already in a negative state which would be the most ambitious of the two states to prevent rust. The best would be neutral but, that would require a hell of a lot more wiring increasing price and fuel consumption not to mention decreasing reliability.
All and all it is bs and not even advertised that well. Not to mention sending any kind of charge not setup normally in the car is bound to mess with thebattery if not sensors.[/quote] Exactly. One needs to know at least basic chemistry to even have a chance at making an effective solution. When Iron corrodes as a base element it goes from FE to FEO2/FEO3. The O2 and O3 indicates oxygen atoms bonding with the iron. The atomic weight and electron count of iron is much higher than that of oxygen so the bond is very unstable and the iron begins to deteriorate. The only way to truly stabilize is to convert it to FE04….black rust.
PS: Steel is an iron alloy and therefore is impure iron. The more impurities iron has in it, the faster it corrodes as well. High Carbon steel will corrode faster than mild steel as well due to being even more impure. Chromium, Nickel and Lead are other alloying elements that resist corrosion. Have you ever wondered why stainless steel has such excellent corrosion resistance and sheen? Chromium is the answer or as the kids call it “Chrome”.[/quote]
Never seen a rusty DeLorean 🙂 or 1999/2000 Volvo V70 XC.[/quote] The Delorean body panels being made out of stainless last longer than the rest of the car lol. There is a common misconception however, stainless can rust. It just doesn’t rust as readily or nearly as fast and must be under the right conditions. Salinity is a common cause of stainless steel to rust.
[quote=”MDK22″ post=138567]or be cheap stainless steel or just be coated and then called stainless steel[/quote] That too. If you weld stainless improperly, you can negate its beneficial properties as it weakens the alloy. Too hot and you’ll be left with a weakened and vulnerable steel and not using a proper shielding gas or flux will allow impurities to rust it as well. Can you tell I enjoy science?
Another condition which will cause stainless to rust is when it’s in physical contact with non-stainless. Join two stainless components with ordinary fasteners and the stainless will rust quickly. Plain saddle clamps and hardware are death to stainless exhaust systems.
They’re snake oil in every sense of the word.
(Nerdy electrochemical/electrical explanation below)
All they really do is flash an LED. Nothing else. In air, the only “electric” way to prevent rust is through galvanization; no powered device will do. Galvanization is more than just a barrier; as zinc is more electronegative than iron, the two metals can be used to make a battery given a conductive electrolyte. In the case of rust protection, this electrolyte is the water/salt spray that hits the scratch spot, and thus one has made a tiny battery, and this battery’s resultant current flow prevents oxidation of the iron at the expense of oxidating the zinc… but given the surface area of a scratch (tiny), this rate of oxidation is low enough that the zinc won’t ever run out (as soon enough it will passivate or the like).
The issue is that the medium (moist air with water/salt spray) isn’t conductive enough in mass. Between said device and wherever rust is starting, sure, the body ground is very conductive but without a conductive second path (which would be the air in between), there is no way to do anything of any significance.
Now underground (especially moist soil) and in water (especially salt water), the conductance is high enough for said methods to work; this is how sacrificial anodes work (hence why all one needs is a block of zinc, not a galvanized coating). Likewise, for such conditions, they also make active (powered) devices which work in a similar fashion (and are not consumable/sacrificial). As stated earlier; unless your car is buried underground or at the bottom of a lake, these methods are effectively useless.
As for such vehicle with the sham device installed being “worse”, my guess is said owners didn’t maintain the body due to either ignorance or assumption that this “device” would make it so they didn’t need to actually take care of things.
Hope I didn’t nerd anybody out, but I figured I had something to add.
[quote=”ratdude747″ post=144263]They’re snake oil in every sense of the word.
(Nerdy electrochemical/electrical explanation below)
All they really do is flash an LED. Nothing else. In air, the only “electric” way to prevent rust is through galvanization; no powered device will do. Galvanization is more than just a barrier; as zinc is more electronegative than iron, the two metals can be used to make a battery given a conductive electrolyte. In the case of rust protection, this electrolyte is the water/salt spray that hits the scratch spot, and thus one has made a tiny battery, and this battery’s resultant current flow prevents oxidation of the iron at the expense of oxidating the zinc… but given the surface area of a scratch (tiny), this rate of oxidation is low enough that the zinc won’t ever run out (as soon enough it will passivate or the like).
The issue is that the medium (moist air with water/salt spray) isn’t conductive enough in mass. Between said device and wherever rust is starting, sure, the body ground is very conductive but without a conductive second path (which would be the air in between), there is no way to do anything of any significance.
Now underground (especially moist soil) and in water (especially salt water), the conductance is high enough for said methods to work; this is how sacrificial anodes work (hence why all one needs is a block of zinc, not a galvanized coating). Likewise, for such conditions, they also make active (powered) devices which work in a similar fashion (and are not consumable/sacrificial). As stated earlier; unless your car is buried underground or at the bottom of a lake, these methods are effectively useless.
As for such vehicle with the sham device installed being “worse”, my guess is said owners didn’t maintain the body due to either ignorance or assumption that this “device” would make it so they didn’t need to actually take care of things.
Hope I didn’t nerd anybody out, but I figured I had something to add.[/quote] Excellent explanation, you put into words my thoughts exactly. Metallurgy and Chemistry are fun aren’t they?
I’ve heard many stories from many people about these little gimmicks and all of them haven’t been positive. This article might be of some relevance; http://www.4wdaction.com.au/forum/viewtopic.php?f=174&t=105702. Unfortunately there’s no easy – instant solution when it comes to rust, just a whole lot of elbow grease. 😉
Chrisco out.
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