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Originally Posted by Canada's Far East
Thanks LEONGSTER - this could be helpful - but I can't find it 
Could you kindly be a tad more specific on where it (rust bug killer) is located.....Thanks |
Roger, it's the last subject on the page entitled : "RUST BUG KILLER". Just in case, here it is:
"Rust bug killer"
I want your opinion on electronic rust prevention - specifically, the RustStop RS2000.
According to this page, it overcomes the weaknesses of electronic rustproofing by using more than one method.
I'm sceptical, but I don't want to get all messy with underseal on my rust-prone car. If this is a simple way out, I'm all for it.
Shuhel
Answer:
I'm sure the RustStop works perfectly, provided you remember to dig a big hole and bury your car in it after installing the device.
You could also drive the car into a lake. Or the ocean. That might screw up the electrics, though. The RS2000 will probably only keep working (battery charge permitting) if the car's buried.
The reason why this thing won't work on a car that's above ground is that there's no circuit between the sacrificial/impressed current anode and almost all of the rustable parts of the car. The conductive tape that you stick the anode(s) in place with means they'll protect the metal right under them just fine, but, y'know, paint'll do that too.
Passive galvanic cathodic protection (your standard "sacrificial anode" system, like when they bolt chunks of magnesium to ships below the waterline) and active impressed current cathodic protection (as used for underground pipelines and other Big Things where there's a long and lousy current path between the anodes and the metal they're protecting) both rely on the fact that the things they're protecting are lumps of metal surrounded by an electrolyte - water or earth.
Iron and steel rust essentially by forming tiny electrochemical cells anywhere that water and oxygen can get to the metal. Zero humidity air: No rust. Iron in a big box full of humid nitrogen: No rust. Iron submerged in salty water that's got no dissolved oxygen in it (which can almost be the case, deep in the ocean): No rust.
The particular curse of iron is that its rust is flaky, so more metal is continuously exposed to the air. Aluminium is much more reactive than iron and corrodes much faster, but its oxide forms a hard thin layer over the rest of the metal and protects it - if something doesn't cut the oxide layer, almost all of the metal survives indefinitely.
To protect flaky-rusting metal like iron, you attach a more reactive metal to it, applying current if necessary to boost the electrochemical path from the iron through the surrounding electrolyte to the sacrificial anode, which corrodes away instead of the iron.
You can demonstrate this effect yourself at home, quite easily; in a bucket of salty water, immerse one "tin" can (which'll actually be made out of steel these days; "tinfoil" was originally tin as well, before aluminium became cheap) and one otherwise identical can with a chunk of magnesium attached to it. Lightweight metal pencil sharpeners are cheap, and for some reason are made from a magnesium alloy, as everybody who had a cool science teacher in high school should already know.
Any way of attaching the magnesium that gives it metal-to-metal contact to the can will do - not glue, but just tying it on with some steel wire would do.
Can A will rust. Can B should remain pristine, while the sharpener slowly disappears. If you leave it long enough, the magnesium will vanish entirely, and then Can B will rust.
Try the same stunt with the two cans just sitting outdoors exposed to the elements, though, and the piece of Can B right under the sharpener will stay unrusted, while the rest of it rusts as normal, because there's no surrounding electrolyte. Rain will form a current path from the magnesium to the steel for a short distance around the sharpener, but most of the can will be unprotected most of the time, and applying a voltage to it won't help.
Modern steel-bodied cars have high quality galvanised panels as a matter of course anyway, which has largely eliminated the rapid-and-serious rust problems that people used to know and hate. They'll still rust eventually, of course, but if you don't scratch the finish and/or expose it to lots of particularly inclement weather, I wouldn't be surprised if a 2005 Toyota Corolla remained cancer-free 20 years from now. Maybe even longer.
A 1985 Alfa Romeo will, of course, probably fit in a matchbox today.
The only really foolproof rust prevention system, of course, is to use one or another "stainless" metal. We may see more stainless steel used in cars in the future, but seeing as it's historically been more expensive than aluminium - which, in turn, is far more expensive than carbon steel - I wouldn't hold my breath for it to show up in many affordable vehicles, if I were you.
There've been a few cathodic protection gizmos for cars in the past, none of which have worked, but the RustStop people insist their product isn't like all those other Scams Engineered By The Barely Literate.
RustStop is stated on various pages to be "the only system to successfully combine both Impressed Current and Sacrificial Anode technologies"... except that impressed current is just a way of making sacrificial anodes work better, so, uh, every impressed current system, uh, combines the "technologies".
They also say that the RS2000 has been "independently tested by an unrelated company" and shown to work, but they won't say who that "unrelated company" was, or where the results can be found. They mention the "tests" over and over, but keep unaccountably forgetting to fill in those blanks.
Instead, they offer testimonials.
No, wait - those are some other equally reliable testimonials. The RustStop ones are here.
And, in a side point, the ruststoponline.com domain is registered by my fellow Australian, Paul Barrs. As get-rich-quick artists go, he does not appear to be a particularly notorious one. But he's still a get-rich-quick artist. Make of this what you will.
While you're making of it what you will, you might also like to make what you will of the RustStop site's numerous irrelevant-link pages, presumably intended to make it look all hip to search engines.
A concept related to impressed current cathodic protection, by the way, is electrolytic rust removal. It really works, and amazingly well; you can use it to do tricks like cleaning up ancient tools so well that you can read the maker's name stamped on them.
To do it, you need an alkaline bath. Some sodium bicarbonate or carbonate in water will do; professional shops use sodium hydroxide, but bicarb or washing soda won't turn your hands to soap nearly as quickly. I've found a large cat litter tray makes a great cheap bath for various hand-tool-sized objects.
You also need a DC power supply. A car battery charger or surplus PC PSU should be just dandy; some sources recommend quite weedy power supplies, because they are weak and have no honour. If you're de-rusting something really big and want the job done inside a week, you'll need a lot of current capacity and enough voltage to push that current through the solution, so something scary like a DC arc welder could be called for.
The last piece of the recipe is a piece of iron you really don't care about. For small jobs, another "tin" can will do. Any plain iron or steel is suitable, but, as a reader reminded me, you should not use stainless steel for this sacrificial electrode unless you feel you need more chromates in your diet.
Connect the object to be cleaned to the negative terminal of your power supply, the sacrificial iron to the positive terminal (don't dip a positive-terminal alligator clip into the bath unless you want it to get eaten), submerge both pieces of metal in the bath without letting them touch, and turn on the juice.
The result will be bubbles, the rapid destruction of the sacrificial iron with lots of 'orrible red gunk accumulating in the bath, and the mystic disappearance of the rust on the object to be cleaned. Just running some water over the cleaned object should remove the loose gunk sitting on it afterwards.
This process verges on the magical the first time you see it, but all it does is remove iron oxide while preserving iron. Actually, technically, it eats a tiny amount of good metal where rust used to be, converting it into a super-thin layer of black oxide. Shiny steel won't be changed.
This process won't, however, regenerate the maker's name on some amorphous blob of oxide that someone dropped in your garden in 1952. The makers of some RustStop-ish gadgets apparently make regenerative claims (or their testimonials do, anyway...). The continuing health of the Bondo Corporation would appear to contradict them.
But since, to borrow a quack medicine favourite, healthy tissue is not harmed, this is by definition the world's least destructive de-rusting technique.
Electrolytic de-rusting does leave a very, very rustable fresh surface, though; anywhere that used to be rusty will now be black and ready to rust again, so as soon as you pull the item out of the bicarb bath, you should give it a coat of oil.
For in-situ de-rusting of bits of cars, houses, battleships and so on, the best quick solution is phosphoric acid products - phosphoric acid is the active ingredient in various "rust converter" paints. The very thought of "naval jelly", however, induces involuntary twitches in many of the world's military personnel for very good reason. If you're going to have to use much of the stuff, serious thought should be given to just selling the car or ship to a suitably gullible person or nation. "
