Car Wash

reeac

JP08 wrote: »

Glad you liked the post ...

Re "properly galvanized" ...



Dr Martin Strangwood, senior lecturer at the School of Metallurgy and Materials, University of Birmingham, says applying a good anti-corrosion coating to a car is vital for a long, rust-free life. He says: “It’s crucial the correct layer of anti-corrosion coating is applied. Occasionally, its protection is used up too soon; perhaps where the metal component is concealed behind a plastic cover and is permanently damp. Also, it’s still difficult to put a thick layer of coating on complex shapes.”
However, for all the car industry’s huge strides in anti-corrosion protection, Strangwood says there’s still one chink in its armour. “Galvanised steel offers only sacrificial protection. The zinc element of it will corrode in preference to the steel. That’s fine because the zinc is not structural – the steel is. However, it does mean the coating has a finite lifetime. To extend it, in winter, people should wash the road salt off their cars.”

I have two galvanised watering cans which date back to the 1930s and both have always lived outside They show some signs of rust but nothing but nothing serious.

facade

reeac wrote: »

I have two galvanised watering cans which date back to the 1930s and both have always lived outside They show some signs of rust but nothing but nothing serious.

They will have been properly galvanised by dipping into molten zinc, and have not been subjected to salt filled clods of damp mud stuck against them for months at a time. With the reduction in sulphur dioxide in the atmosphere due to the clean air acts, and the death of most industry, if you are well inland they could last 100 years or more, if you keep them away from rain, as the acid in rainwater will eventually remove the zinc.

Cars are electro galvanised with a microscopic layer of zinc, which is better than nothing, and has been shown to be more effective than the old zinc phosphate dip but it isn't corrosion proof by any means.

JP08

As I understand it (and that's not too much) "proper" galvanizing involves heating the object to some pretty high temperatures. This may well have been done to your watering can. It isn't done to cars as the temperatures involved would cause too much distortion. This is not critical for a watering can or a bath, but obviously is for a bodyshell.

The process used on car bodies, I believe, is called "hot dipping" and provides a lesser level of protection.

Cross posted with Facade and his better answer - sorry.

Grouchy

Thanks I will pick out the relevant bits from the replies.