Salt on the road
Discussion
Ummm, Aluminium actually corrodes faster with salt water than steel rusts. Spent a lot of money de-corroding and corrosion proofing aluminium aircaft based at seaside airports.
www.terrific-scientific.co.uk/Topics/Corrosion/Explain/Corrosion-6.htm
>> Edited by hbaumhardt on Sunday 20th November 16:03
www.terrific-scientific.co.uk/Topics/Corrosion/Explain/Corrosion-6.htm
>> Edited by hbaumhardt on Sunday 20th November 16:03
HB - I cannot argue with your aircraft background - I am sure you know a lot more than me about this. The article you linked to is rather scary - I guess my knowledge of aluminium corrosion did not factor in the salt part! Oddly though, all the elise chassis I have looked at - even from old cars, seemed to look fine in contrast to steel chassis (unless really well galvanised). For example my undertray looks OK, but steel parts of the suspension look really rusty. Is this some sort of treatment the metal receives or am I being wholly ignorant? After yesterday's drive to Bedford where I stupidly followed palmersports directtions, I felt like I was skating on a few of the back roads. I'd rather have the salt than a crash. Maybe a runabout is in order for the winter.
I do what bogie suggested and clean regularly with a jetwash. At least the fibreglass doesn't rust. I suppose I won't be happy if the chassis collapses then.
>> Edited by shangani on Sunday 20th November 16:35
I do what bogie suggested and clean regularly with a jetwash. At least the fibreglass doesn't rust. I suppose I won't be happy if the chassis collapses then.
>> Edited by shangani on Sunday 20th November 16:35
I'd just continue to use it through the winter. The only parts that will be affected are wishbones and driveshafts etc - this is just cosmetic and nothing to worry about.
All I'd do it jack it up every 4 weeks and jet wash the underneath off. If you jack it at the back of the tub you can tilt the whole car on it's side and do it. 10 minute job.
I also tend to give mine a good clean come March with the wheels off etc. Spend about an hour on it then.
All I'd do it jack it up every 4 weeks and jet wash the underneath off. If you jack it at the back of the tub you can tilt the whole car on it's side and do it. 10 minute job.
I also tend to give mine a good clean come March with the wheels off etc. Spend about an hour on it then.
I studied Chemistry and Material Science at University and can confirm that steel chassis will corrode a lot faster than an Aluminium one. the actual Aluminium metal will initially corrode faster from when it is new, infact as soon as Aluminium is exposed to the air it will start to corrode (oxidise), but aluminium creates an protective oxide layer that protects the metal underneath. Iron on the other hand forms a loosely bonded oxidative layer on the outside which will fall off leaving more of the metal underneath to then be corroded. This oxidation process continues in the iron until there is nothing left, ie all the iron is oxidised.
The Aluminium remains protected by its outer oxidsed layer which will prevent further oxidation. A problem can occur if oxidative layer was being removed all the time, eg stones hitting it and removing the protective layer causing rapid corrosion. This wont happen though as the under tray will prevent it.
It is wise to wash the salt off, as this will eat through the oxide layer and cause more metal to be exposed and therefore corrode the chassis.
Hope this will clear things up a little
Nick
The Aluminium remains protected by its outer oxidsed layer which will prevent further oxidation. A problem can occur if oxidative layer was being removed all the time, eg stones hitting it and removing the protective layer causing rapid corrosion. This wont happen though as the under tray will prevent it.
It is wise to wash the salt off, as this will eat through the oxide layer and cause more metal to be exposed and therefore corrode the chassis.
Hope this will clear things up a little
Nick
Thanks bogie - I guess I will be driving to work in elise after all - besides, the faster the engine ages, the more I will be able to justify a honda. BTW - when are you next at Bedford - I want to see this beast of yours. HBaumhardt said you took him for a pax lap at Bedford a while back and he said it was seriously quick - and he ain't the slowest I have seen!
hbaumhardt said:
Ummm, Aluminium actually corrodes faster with salt water than steel rusts. Spent a lot of money de-corroding and corrosion proofing aluminium aircaft based at seaside airports.
www.terrific-scientific.co.uk/Topics/Corrosion/Explain/Corrosion-6.htm
>> Edited by hbaumhardt on Sunday 20th November 16:03
Um no. Aircraft use is very different. Aluminium does oxidise very quickly in air (and salt) but what actually happens is as soon as the aluminium hits the air a thin layer of oxidied aluminium forms over every exposed area. This is a very tough skin and then resists corosion and protects the "core" of the material.
I havnt read your article but from what you have put here it is misleading as the application will be different. Aircraft aluminium is stressed and acts as an integral part of the structural integrity. The temp cycling from hot climate to low pressure cold air to dense air and heat etc will stress any material.
The problem with corosion and the liz is the suspension arms. These have a habit of rusting. I shouldnt worry. As Bogie says it is a car, use it.
Sorry NickJ, I typed this before I read your reply. Spot on mate, I come at it from an engineering materials study route!
>> Edited by gooby on Sunday 20th November 19:12
Thats what I think, a car is in the first place not a showroom! but more a adreline thing, something thats give's you a smile on your face when you drive from A to B, ofcorse its nice that its clean and looks good, but in the first place it has to drive
I take my car everywhere even when I go out and shop, I like driving in special cars when I can, so I take my car on every trip you can take a car too, enjoy your live and driving the best way you can...when you want to polish cars work in a polish shop or you can polish mine when I'm not driving
René
I take my car everywhere even when I go out and shop, I like driving in special cars when I can, so I take my car on every trip you can take a car too, enjoy your live and driving the best way you can...when you want to polish cars work in a polish shop or you can polish mine when I'm not driving
René
Without labouring the point, many folks think that Aluminium is A-OK as it doesnt "rust" and just leave it. In water its sort of self protecting, but in salt water it will keep corroding (faster than a ferrus metal) so wash the underside when the gritting stops in the spring. Easy, no post-grad qualifcation requried.
The procss used in the manufacture, hot extrusion, will "anneal" the external structure of the aluminium. This means as the outer surface of the material cools at a higher rate than the inside, the outer surface is like a shell the grain structure of the outer surface is smaller and finer than the inside. the inner grain structure is longer and more flexable. In effect the structure of the material mirrors the mechanical effect of a miniture I beam. Very clever engineering! Then the shell of alu oxide on the outside of this. As far as I remember, alu oxide doesnt combine with common salt very well so I cant see it be eroded away very quickly. By far the biggest problem will be the abrasivness of the salt / grit mixture spread on the road.
I wouldnt worry at all about aluminium corrosion. I would show concern about water getting in adhesive joins and freezing. As I have never heard of this form of failure I can only assume that the engineers at lotus are far better than me.
surprise surprise!
I wouldnt worry at all about aluminium corrosion. I would show concern about water getting in adhesive joins and freezing. As I have never heard of this form of failure I can only assume that the engineers at lotus are far better than me.
surprise surprise!
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up your car in the long run.