I'd always worked from the premise that the more cr@p you can layer on the car, the better the protection.

I may be wrong but I think a 3 year old Mazda 2 (= Ford Fiesta) will have a galvanised body shell,

I lived in Ontario for 35 yrs ; 20 yrs in Sudbury, and 15 yrs near Guelph. I had the underneath of my car sprayed with oil each year. I owned it for 28 yrs and it was still in very good condition when I sold it before moving to BC. No rust even though in Sudbury it was parked outdoors winter and summer

Agreed! Annual application of such as KrownRust (around $100 give or take) is a sound investment imo if you wish to keep a car for more than a few years from new. I believe Calcium Chloride is an ever increasing component for treating roads these days an is very corrosive on steel. A consideration is also high humidity in summer which also attacks steel. Much depends on where you live/drive but for the cost of treatment annually for me its a given. Just an opinion.

If it's a long term keeper the rust proofing is probably worth it. Krown is (I think) the original and I paid $135 for this last year, but there are cheaper similar treatments around that are closer to $100.

I know it all comes down to cost, but would be nice if they used non-corrosive materials on roads like they do at airports, since using salt or high corrosive substances is a no no at those places.

But it all boils to cost I suppose.

Car Washing downtown is bitch this time of year. I usually wait out for the spring. I don't mind driving a dirty auto mobile. Makes me look rugged when I don't shave and put my Timberland boots on :-) Oh wait this isn't the red kneck thread :-(

This'll fix the problem . . .
BBC News - Laser-etched metal 'bounces' water

Had my truck for 2 years (almost). Never washed it yet. Will do so before it gets returned at the end of the lease in March I suppose.

Road salt & associated corrosion is one reason why I choose to lease rather than buy.

If we lived in the city we would consider leasing as we could get a bigger more comfortable car leasing where when buying we can't get anything but a sub compact with basic stuff.

But we live semi-rural and isolated, and my commute alone would put on 20,000km a year, and from what I know, they usually don't go above 24,000km on a lease?

We just do too much driving for a lease and I'd be too nervous about going over the allowed limits.

This time around we really had no choice but to buy, only 1 bank approved us and it was for a purchase and only for a used car, we don't have high income, and no credit other then student loans, so banks are not eager to do business with us.

Mazdas seem to be notorious for rust. I can't see any underseal on our Civic, but it's all galvanized metal so there's really no need. No rust after six years, either.

Of course I don't believe they use much salt on the roads around here, mostly just sand and gravel.

I've heard under a certain temp salt isn't effective since it only lowers (or is it raise?) the freezing point, and if its already that cold, no real point in using it.

I've seen salt, salty liquid, as well as sand being dumped onto the highway, sometimes just one of the 3 and sometimes 3 trucks in a row, with each truck dumping something different.

The sand/gravel makes a complete mess of everything as well.

Yes. I remember something in a news story last year when we had a big (~20 vehicles) crash due to icy roads where the city guys said it was too cold for salt to be effective.

We get a car wash seasons pass in the winter. Petro Canada sells them at $180 for 95 washes in 95 days. (Limit 1 wash per day.)

The SuperWorks (highest level) wash you can get for $9 per wash if you load up a reloadable card (otherwise about $14 at the pump), so that makes your break even point $180/9=20 washes... or one wash every 4-5 days.

We split the card with our neighbour and pass it back and forth every 3 days. We both have two cars, so we average usually 4-5 washes every week... we have already passed 20 washes in about 30 days, so washes for the next two months are effectively free.

Not a bad way to spend the money. Keeps the cars clean as they are regularly going through the wash, keeps the salt off, keeps the undersides rinsed. Works for us.

If you'd listened to the science teacher when you were a toddler, you'd know that Mr. Fahrenheit based his zero point on the lowest temperature he could manufacture in his lab, which was the freezing point of a saturated NaCl (brine) solution.

0 degrees F = -17.8 degrees C.

Below that salt is useless.