Yeah, well i bet your customers did not have their trucks sprayed with Krown, did they? It is sprayed inside every rocker, cab corner, frame, tail lights get removed and the inside of the box gets sprayed, as does in between the box floor panels. My truck drips for days, every nook and cranny is protected before old man winter sets in.
Getting a vehicle undercoated whether it is Krown, Rust check or even fluid film, if you do this a vehicle will be rust free and last a long time.
I get your point about the importance of undercoating every year. I have undercoated my 2011 f-250 every year since I bought it. It was 1.5 years old and brought up from Florida, so I don't think it saw any salt in that first year and a half unless someone used it to launch a boat. I still have had had a couple rock chips around the rear wheel wells that needed touch-ups and the bottom of the rear fenders were both stripped clear of paint by rocks on dirt roads, so I had to fix that up too because it was rusting. My point being that undercoating is a big help at keeping the rust at bay, but it isn't going to do everything. When you get rock chips, steel will rust, then peel, then rust, then bubble, then the damaged area expands, etc. Once it starts, it is near impossible to stop, and if you don't catch it right away the corrosion will work its way under the paint to areas that aren't even exposed. When aluminum corrodes it is different, instead of peeling and bubbling it makes a thin film over the exposed spot that helps slow down further corrosion. Yes another rock impact will expose it again, but then it will film again. It isn't perfect, but exposed aluminum is definitely slower to corrode than exposed steel. Time will tell I guess, but after the dings and nicks that tend to peel away the protective paint coating and allow rust to start, I would expect aluminum fenders to stand up to being exposed a lot better than steel.
It is different for the folks south of the snow belt. You have the same thing in Ontario as I do, so you know it really sucks to watch your perfectly functional vehicle with lots of life left in the engine etc, fall apart due to the body corroding out from under it. There is a diminishing return to spending $1 to 2k to repair rusty wheel wells and door sills, only to have it come back in a year and a half. I will be interested to see in 8-10 years if the aluminum vehicles (all other things like care and undercoating being equal) stand up better over time to the damage from road salt.
South of the snow belt you can say that it is more expensive to repair aluminum than steel, but up here you have to factor in the fact that even if the repair is done professionally a steel fender repair is going to rust within five years or less, so you will then pay for the repair twice or have to sell the vehicle with severely lowered value. I had a Subaru that had an accident (side impact in the rear fender) when it was 6 months old. Even with a professionally done repair that looked immaculate, by the time it was 6 years old that one fender and wheel well around the accident was a rusty mess, while the other three fenders were still immaculate. If that repair had been to an aluminum body panel, I would wager it would have been a better result. Not as perfect as the undamaged fenders, but definitely better than steel.
