I just read ALL 12 pages. Luckily I'm on vacation... So I can post my own babble now!!!
If I may wade into the discussion...
I've had a few cars and lite trucks sprayed with a variety of products over the years. Some already were rusty, and now I bring my vehicles in from the west coast, so rust is ZERO, like they are new, even tho they're 15-20 years old.
I had my '80 Caprice wagon sprayed by Metropolitan in Montreal, prolly 10-12 years ago , and I paid the tech(?) an extra $20, and my wagon was on the lift for 3 times as long as the other cars! It dripped for weeks, but looking WAY back, I think they were spraying the cheapest product available, and it didn't stick or resist wash off from road spray.
In 2007 I brought back a 1984 Chevy Suburban from San Francisco. I had minimal rust on a few parts of the frame and body. I made a video of our arrival at the sellers house. So the rust can be clearly seen in the videos. Obviously I didn't want the road salt and damp air to turn my long dreamed about rig into a pile of orange dust, so I considered Metrolpolitain... I knew it was a poor choice, but...
Luckily, I stumbled across a fellow on the south Shore of Montreal that sprayed a thick, but creepy grease. I dropped off the Truck, and when I returned that evening, it was obvious he had missed a variety of easily seen areas, mostly in the back/underbody area.
I brought these to his attention, and he lit up another cigarette, and used a touch up brush to slop on a bit of product/grease on the receiver trailer hitch, etc... Hardly what I had in mind. I had watched him start the job earlier in the day, and he used a Graco airless sprayer, and a 55 gallon drum of some rust-preventative goop. He had drilled a variety of holes in the rockers as I watched.
Anyways, long story shorter,
I watched the rear axle, driveshaft, leaf springs turn orange with rust over the winter. I returned to him next fall, and he didn't even spray those rusty areas, and told me thye were thick steel, so didn't need treatment! What a JERK! I also had him do my just imported '93 Hyundai Excel. He did a much more complete job on this car, but didn't spray the engine and tranny, as I asked him to do on the Sub. He said it would smoke. I said
SPRAY IT!!!.
So now the Sub engine is coated, and nothing is rusty, but the Hyundai has corrosion on the aluminum tranny and variety of coolant pipes, alternator etc...
But this is just the beginning of my story!
I imported a 1984 K5 Blazer from Oregon. This had some rust on the rockers, but otherwise, black paint on the frame. I decided to try another rust-proofer. I looked up Krown, and brought the Blazer into the Verdun location. This time I planned to hang around with the tech, and since it was after 6, I was the only one around, and the tech allowed my to point out areas I thought he should spray.
He just kept on spraying as long as I pointed... Top of fuel tank, inside rockers, (they were rusted thru on top, from rain getting caught under rubber moldings). inside roof pillars after drilling holes, everything under the hood, and on and on!!!
Bottom line w Krown? It's totally useless on wash areas. A few days later, the front and rear inner fenders were DRY!!! I called Krown in TO, and they said they had success in zillions of cars, years of successs, etc... That it was invisible protection. I'm not blind, this was not invisible, it was gone >ZERO< evaporated!!!
So..... I washed the truck after EVERY salt storm, and eventually started spraying White Lithium Grease on the springs, wheel wells and wherever else the Krown disappeared from! What a disappointment!
So summer 2011 is here, and I'm poking around looking for a way to this MYSELF! I was a licensed mechanic, so very familiar with all things cars and trucks. I bought an airless paint sprayer at the big box store, heavily discounted, and all I needed was a solvent free product to spray. I called a place in Blainville Quebec, and the clerk faxed me some info, but even tho he claimed solvent free, I never made it up to their showroom.
I then received a recommendation to use a product (shameless plug coming) called Fluid Film. I bought a rattle can at the local John Deere dealer, and liked the consistency. I read the blurb on their web site, and ordered a 5 gallon/20 litre pail, which for $200 US included an aluminum spray applicator, (compressor requ'd), 1 spray bomb, and two 1 litre bottles for the stuff in the pail.
By this time, it's October, and I'm on my way home with a 1995 Suburban I bought in Phoenix. This would be my wife's winter daily driver, so rust protection was mandatory!
Moving back to my daily driver a bit... I put the '84 Suburban (from SF) up on tall jack stands, and sandblasted all the rust off the driveshaft, diffy, rear frame, etc... Alot of work, but I didn't believe ANY rust preventive would protect already rusty areas. I used 8 bags (22k's each) of fine grit Black Diamond grit, and painted the now bare areas with dark grey primer and satin black paint from spray cans. The rust was really surface rust, as various imprinted numbers (on the diffy, backing plates) appeared after blasting.
Now it was time for the Fluid Film! I sprayed about 4 litres of the stuff all over the now dried black paint, and it took me about 5 hours to get into all the areas. And this was already a greased up truck, except as mentioned earlier, in the rear!
Why so long??? I'm THOROUGH!!! I removed the taillights, grille, and sprayed till my hearts delight! I then moved onto the Hyundai. I lightly wire brushed the rear fender wells, to remove the sand/mud theat the grease rust proofing attracted, and was pleasntly impressed to find shiny black paint. Unfortunately, the smoker fellows product has caused the door mouldings to swell. The solvent at work... Shame! I then re-sprayed in Fluid Film, including the brake drums, inside the alloy wheels, and all over the now slightly corroding transmission and engine. Remember, when I brought this car from Phoenix, it looked BRAND NEW under the hood. ZERO corrosion, gold chromate plating EVERYWHERE!!! Just like it was NEW!!!
I then moved onto the Arizona Sub. It actually had some very lite surface rust on the frame. It must've been driven in a bit of salt somewhere in it life. Oh well, I bought the only rusty truck in Arizona!
So I spent at least 10 hours over a few days spraying this truck. Removed tailights, parking lamps, sprayed into rocker weep/drain holes, etc etc... And I didn't even do inside the doors! For those who think it takes an hour or two, I invite them to watch my videos. Spraying a large truck THOROUGHLY and completely is VERY time consuming, especially when one doesn't have a hoist. (It's on my bucket list).
Bottom line, so far, I'm VERY impressed with the Fluid Film. It has a desirable viscosity, and seems to be resistant to wash off in the wheel wells. It barely drips, I'd call it less than 1%, and I sprayed it heavy! Contains no solvents, so no rubber swelling.
Concerning wash off, I sprayed the leading edge of the leaf springs on my '84 Suburban with "Fluid Film" on one, and "Amsoil Metal Protector" on the other. After a few hundred miles in fall/warm weather, the FF was still clinging quite visibly to the spring. The Amsoil MP had dried to a waxy residue. I would say they're both quality/effective products, though I didn't inquire to buying Amsoil in bulk. I don't know if it has solvent. maybe it would be better on areas that one may brush against, and get the FF on their clothes.
Fluid Film Is sold in the USA by Kellsport.com for $220 US for the "kit", but for more than double in Canada. Maybe a trip to a US PO Box would save a few bucks??? I won't post any links to products, even tho I really liked the Fluid Film. It's easy enuff to look up using any search engine.