aluminium corrosion

marp68

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I usually have the bike indoors in a warm place. This is what happened after having it outside for a week under a bike cover. :yikes: It rained some times during this time, but it stood on pebbles/sand. Has anyone experienced this? I disconnected the battery and after a few weeks now it's the same. I experienced the same thing, even worse, last summer, but then it was parked on grass, so I thought it was because of the warm humidity coming up from the grass in the extremely warm weather after a heavy rain.

I've measured for any current leakage, but that doesn't seem to be the case. I disconnected the cable from the - terminal and measured between them according on how to measure current leakage. Set to 20 mA the meter only reads 0,14 which I suppose means 0,14 mA. In all places I've read it says that under 50 mA should be okej. Or could it still be current leakage that has caused this? Or what else? I'm horrified.:( Is it not possible to park it outside?
 

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Cheap covers are worse than leaving a bike uncovered.
A good cover not only keeps stuff off the bike they let moisture evaporate away.
So shiny stuff gets crappy quick under the cheap covers. An old bed sheet works well. It lets moisture out.
Parking the bike inside on bare concrete under a cover is bad too. Concrete gives off powder, this powder rises up an settles on the bike under the cover. Better to put a tarp down under the bike then cover or leave it uncovered. At least uncovered you might notice this dust collecting and clean it off.
Leo
 
So you mean this is normal?

Yes, when parked inside I used just an old bed sheet made of cotton to protect it from all dust in the cellar.

The cover I used outside is very old and it is probably made of nylon. Nylon is not completely rain proof but breathe some, so I thought it would be okej, since bike doesn't generate any heat (like a body) and it was only around 15 degrees Celsius. What should one use if one would like to protect it from rain, dirt etc when parked outside? Goretex :confused: Or without any cover and wash it more often...

So it can't be anything electric, then? Anyone else that has experienced this?
 
Is that pitted, or just oxidized? Aluminum, if I recall correctly, has a natural oxidation process that essentially looks like that. However ,if it's pitted, then I would suspect electrolysis...which means water/electricity is eating away at the weakest metal. I've see this on my boat in salt water when my sacraficial zinc plate is corroded beyond benefit...never really seen it on a bike.
 
If it's staining and can polished off, it's pretty much aluminium oxidisation

If it's pitted, potentially electrolysis but also consider any environmentals causing the water to gain an acidic factor. Perhaps something on the cover. Get some litmus paper and give it a dab out of curiosity
 
As far as I knew, the general light oxidation process only make the aluminium turn more grey. Is it really possible that this is only because of the bad bike cover?

On the wheels it was pitted when I bought it, but I polished as much as I could. But there are still small holes on the inside. The outer side of the rims were alright though. Since then I have always stored it inside in a warm dry place with an old bed sheet on.

On the engine cases there are so far only white powder that haven't eaten so much, so it was possible to polish off.

But, yes, I think there has been some sort of electrolyt process due to bad combination of humidity after rain, the bad bike cover and perhaps some sort of current leakage. Is it even possible with a current leakage when the meter read only 0,14 mA? The only way to test it will be to let it rain with the cover on but no battery connected.

Intresting idea about something on the inside of the cover and the litmus test. Should I wet the paper before using it?
 
Hi marp,
a lot depends on the atmospheric conditions are like where you live.
Here on the Canadian prairies I parked bikes outside unwrapped under a carport all winter with no ill effects. Minus 30ºC and just about zero humidity will do that.
Sweden suggests salt-laden sea air, extreme humidity and ~5ºC, Optimum atmospheric corrosion conditions.
 
Sitting on stones isn't a good idea, worse than sitting on a concrete pad. Moisture will be held under them when they look dry.

I live in North Queensland, Australia, in a high humidity area and a lot of condensation in winter just one road back from the ocean and i don't have that problem at all. I use a combination of WD40 and Lanolin oil on all my vehicles. With any wet riding or transporting/trailer of the bike i use a liberal amount of WD40 over the whole bike and then when it is dry i use do another light spray using a rag to wipe down the bike. The WD40 dissipates the water and leaves a film that helps to stop oxidization.

I have very rarely washed my bike with water and soap. Only after an especially dirty wet rid and then i go through the process of the WD40/Lanolin oil again.

Lanolin Oil will stop metal rusting after it has been submerged in the ocean, spray it first :D. I use it on all my vehicles as well. It is a water dispersal as well and can be used on electrical wiring and gear without conducting. I spray on my bikes and using a clean rag wipe it around. Dust will settle on the Lanolin because i is sticky, just spray a small amount on a clean rag and re-wipe and it will be as shiny and clean as before.

Lanolin oil is a decrease as well, use it around those pesky areas like the front sprocket and it will be easy to keep clean

I buy both WD40 and Lanolin oil in 4, (WD40) or 5, Lanolin Oil), liter containers, using a spray bottle for disperment.

This system works, I have an engine i had neglected for a while, after polishing with 1500 grit polishing and wiping down with the Lanolin oil, it had become quite dull without oxidizing, taking a rag with some lanolin oil on it i gave a good rub over and it come back as good as.
 
Shop around for a new cover. Don't cheap out, but a good one. Ask around at bike shops, bike nights, swap meets. Most anyplace bikes congregate.
Leo
 
You might try waxing the alloy surfaces after polishing. That may help keep the corrosion at bay.
 
In the corrosion process, electrons pass from anodic areas to cathodic areas in the presence of electrolyte (moisture). Commercially pure aluminum all, but stops corroding once that first very fine layer is formed. I suspect we're dealing with alloy here. That's going to get a lot worse. Clean it up with aluminum wool, Scotch Brite, or a stiff bristle brush. Brass is OK. Get some good polish and/or wax on it. Get a cover that does't trap moisture. Removing the electrolyte (moisture) from the triangle will stop the corrosion.
 
Thanks for all feedback. Probably a bad combo of a lot of things

I've lightly polished the rims and other aluminium parts a bit. Yesterday it rained, so keeping an eye on the bike will tell if the disconnected battery helped anything. Has anoyone heard of putting the center stand on a piece of wood, to avoid it being grounded (with connected battery)?

Will definitely try something like Lanolin oil. Have tried to google on Lanotec Lanolin oil, but no hits in Sweden. Similar products? Paraffin wax or litium oil...

I've come to the conclusion that my bike cover is actually quite good. At the top along the bike is a more nylon based part, then on the side there is more of a nylon based canvas material that seems to breathe better than the top material. I can even blow through the nylon on top putting some force to it. And part of the cover where the mirrors normally go there are a sort of ventilation holes but covered so that rain from above can't find it ways down. But i think I will wash it to get rid of any potential salt water dust on it.

Another intresting thing though is that the bike is parked behind the building which is lower, a sort of howe/dip and has bushes and tall big trees around. No much sunlight there and especially around the bike the sun never shines due to trees and a small hill, so perhaps rain is accumulating more around the bike and creates moistering during a longer time around the bike. I usually don't park on the street, since I then have to move it every week due to street cleaning. So, if they don't let me park no more in the bicycle cellar I will probably ending up standing on the street or put some flat parking stones under the bike, so that it dries upp more easily. Don't know where to store it during the winter though. Outside is bad enough.


Well, well...
 
You might try waxing the alloy surfaces after polishing. That may help keep the corrosion at bay.

This would be my method of approach as well. A good wax like Renaissance Wax would be perfect for surfaces. A spray of some kind will get into the nooks and crannys.

I like to use Boeshield T-9 for that. The stuff is excellent. It forms a tight barrier against corrosion. It was developed by Boeing for use on aircraft... which are mostly aluminum. :wink2:
 
Know anyone who has sheep? You can usually find gobs of it in the crease between the belly and rear legs. You might also search "wool grease" as most hits for "lanolin" return as cosmetic uses.
 
Hi marp,
like WER says, lanolin is nature's way of waterproofing sheeps' wool and has to be removed before the wool can be processed.
In most places you can buy lanolin by the jarful to use as a mechanic's hand cream.
As I found to my embarrassment the first time I tried to buy lanolin here in Canada when the big ol' jar I brought from the UK ran out, it's sold here by pharmacies in high priced tiny tubes for nursing mothers to rub on their nipples.
 
I bought a gun from a dude once who used lanolin for reloading bullets.
 
The pitting holes inside the rim could perhaps also be from brake dust.

Anyway, I found the Renaissance Wax in Stockholm. Interesting. But, what about ordinary car polishing wax? The wax you can put on afterwards to get a hard protection surface.

Yes, I found a lot of writing about lanolin in different forms, with and without water. I suppose one should use the heaviest one without water in it. Seems to be used in many beauty or skincare products. But very expensive... I will check out some mechanic hand creams as well.

I don't need the aluminium to be extremely shiny, but I will definetly take better care of these parts from now on. Some sort of spray would be best I assume.

Any tip on how to get rid of the darker color in the pitting holes? Very hard if you don't want to blaster the away.
 
Any tip on how to get rid of the darker color in the pitting holes? Very hard if you don't want to blaster the away.

Scotch-Brite pads are appropriate. Don't use a steel or copper wire brush. Do not use steel wool or a copper scrubber. You'll introduce galvanic corrosion. Aluminum wool is good to use.
 
I have been using lanolin oil for so long i didn't think it wouldn't be unavailable over seas. Used to be a couple of manufactures but now there only seems to be one.

European distributors of Lanotech lanolin oil is in Ireland, maybe they have someone closer to Sweden that sells for them?

http://dkfltd.com/en/index.html

I don't have any shares or any ties to this product. It's just so dam good, it would have been sold in the old wild west as to cure everything from piles to making you attractive to every women you met.
 
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