I’ve been in Australia a bit too long and have started to clean my bicycles and other stuff. A couple of my bikes are vintage (1980s) with heavy chrome. How to clean it? Over the years I’ve worked this out fairly well. But I thought I’d look on the internet. Oh my. So many mistakes there. Also, some very good ideas, but crazy ideas about how and why they work. Here are the facts. 100% factual, 100% guaranteed.
Ever thought- Why does my shit get rusty? No? Yes? Here’s the definitive answer. Rust is iron combined with oxygen. For iron to react with oxygen, it helps if surface is wet. If the iron is touching a different type of metal, there will be electrolysis. Electrolysis means ‘battery death’, so it’s really quite bad. If the moisture is salty and if the temperature is high, rust forms faster.
One last thing is needed for problem corrosion. The oxygen in the air has to be able to get deep into the metal. For metals like zinc and aluminium, a surface coating of rust forms, then the reaction stops. But for iron, the rust gets crusty and forms pits and falls off, exposing fresh iron to be converted to rust. Even worse, the rust forms crusty pits that retain moisture and further encourage rust. That’s why rust spreads across a surface like a disease. Rust creates rust. Bummer. Ok, that’s enough of the science lesson. Now some of the ideas in the methods section won’t seem so weird.
1. Steel wool. Fine grade.
Unless you only need the chrome to look good for a month, DON’T DO IT. Steel wool takes away the surface rust, and works great as a cleaner. But it doesn’t do anything to treat the rust or prevent more rusting. In fact, it will leave lots of steel particles in the cracks and pits and they will rust really fast and easily. You don’t want to be feeding the rust pits with soft and reactive iron particles. But IF you insist on using steel wool, you must seal the chrome with a clear coat or regularly polish it with a good quality wax, so that the air and oxygen can’t get to the iron.
2. AutoSol, Brasso and other rust-converting pastes.
These contain mild abrasives to remove the dirty rust particles, but also contain ‘sacrificial’ metal compounds that ‘suck’ the oxygen out of the rust. Brilliant idea (pun intended). With less oxygen, the rust is converted from an ugly red compound to a grey/black compound. When combined with a good quality clear coat or waxing, this method works really well, and slows down the re-emergence of rust for longer than other methods.
This rear hub off a bicycle is good quality chrome and has come up really well with some AutoSol and a rub with Turtle Wax.
3. Paste cleaners.
There are lots and they are mostly ok in my experience. Definitely not as good as a rust-converting paste. But if you follow up with a clear coat or wax, this is quite good. Some take a bit of elbow effort. There are many others. Some people even use toothpaste. I might have used it, and it is definitely not going to scratch the chrome or paintwork, but it doesn’t ‘cut’ the rust away very quickly or easily.
4. Wet and dry sandpaper.
400 grit wet and dry is an aggressive cleaner. Personally, I think 800 grit is safer and less likely to leave rub marks. 1200 or 1600 grit gives a final clean. Sandpaper has the huge advantage over steel wool that any residues aren’t going to rust. But a clear coat or wax to keep out the air and oxygen will be helpful to keep the surface shiny.
These wing nuts were very corroded and rusty (right), but came up ok after rubbing with some 800 grit wet and dry, then some AutoSol, and a finish with Turtle Wax (left). I spent about 5 or 10 minutes working on each of these. They are quick-release nuts for the front axle of a bicycle (1980-era).
5. Cutting compounds and waxes.
These are ok for light rust. I like Meguire’s Medium Cut and Polish. It contains siliceous earth compounds (that’s just fine sand to normal people).
Waxes are totally important as a finish because they repel water, and exclude air. They are what will stop the rust coming back.
Which wax? Well, I’ve tried a few, but after hearing that the Harley Davidson riders use Turtle Wax, I’ve been using it and I’m very happy with how it works. There’s a bit of solvent type cleaner and some very very fine cutting compound in it that makes a surface really shine. Those Harley riders are obsessed about their bikes and I totally agree with their choice of wax.
6. The secret method
The only secret about the secret method is how it works. There is so much garbage on the internet about this method that it probably works out to about 350 kg of garbage for every person who reads the internet. (The same number of kg per person as the bombs that the US dropped on Cambodia during the Vietnam war. A coincidence? I don’t think so!)
The method is to rub the chrome with aluminium foil, wetting it with cola. Seriously, that’s it. It works, and works VERY well.
Why? As noted above, some metals react with oxygen in the air and form an inert layer. Aluminium foil isn’t a really shiny metal (like new coins for example) because it reacts instantly with oxygen to form a very thin white cover. But when rubbing the chrome with it, the oxide is removed, and it magically sucks the oxygen out of the iron oxide. Same deal as the rust-converting pastes mentioned above. But what about the cola? Well, believe it or not, one of the ingredients of coal is phosphoric acid. In stronger forms, phosphoric acid is rust converter, because it can suck the oxygen out of rust. Cola is weak rust-converter. Because it is a liquid, and it absorbs oxygen, it helps stop the aluminium foil from oxidising through contact with the air, saving it’s oxygen-sucking power for the wet rust.
People wonder whether it’s the gas or the carbonic acid in cola that does the job. Probably not, I’d say. Is it the magic black stuff? No. Is water as good as cola? Maybe, but cola contains rust converter and is very cheap, so why not use it? Is diet cola better than sugary cola? Many people say regular cola is better, and have chemical theories about sugar. I say that diet cola is better because it’s not sticky and won’t attract dirt and stuff. Sugar also attracts moisture, which isn’t a good thing.
At around 3:00 minutes into this video, the MythBusters use the cola and aluminium foil method. Check out the results when compared with a premium chrome cleaner.
Of course, use a good quality wax after using the magic method, or any method. Have I said that enough by now?
May your cleaning be quick and good and your life be long and happy.