Originally Posted By: JHZR2
You can use an airless sprayer for fluid film. They can be acquired rather cheap. Cut with a little mineral spirits if needed.
I prefer oily coatings. You can spray them via compressor. Works well. It doesn't take a lot. Avoid spots where you know it will all be lost in the first rain. Look for spots where you don't want water to hide...
I usually buy the cheapest plastic drop cloth, a cheap tyvek suit, and the best PPE I can find. I use UVEX goggles and a 3M respirator with the appropriate filters. I put down the drop cloth, hold it down in front with ramps, drive up the ramps, and then climb under to spray. Don't stay under too long.
A curved spray tool works well to get into the doors via the drains.
My setup was pretty much the same, only I tossed soft clean drop cloths over the vehicles and wrapped the lower section with wreck wrap, after I shot the insides of the doors. That resulted in no overspray on the vehicle. I did my Liberty and Rubicon with a product that has similar viscosity to FF, maybe a touch thicker before thinning it. In both instances I used my rustproofing gun to do fenders, rockers, inside doors, and the other difficult to access areas. The airless offers no access to shooting insides of doors, etc. After doing the difficult to access areas I shot the bottom of the Liberty with the rustproofing gun, and the bottom of the Rubicon with my airless sprayer. The airless lays down a nice thick coat with little to no thinning of the product, if you desire to do so. You can also cut it and use a bit less pressure and a smaller orifice tip. I was happy with the outcome of both. The other downside to using the airless is there's cleaning another tool which takes about 20 minutes or so and up to a gallon of thinner, depending on what is needed to clean up the product you use, and the size of the machine. You will also use more material. The airless gun is easier to maneuver especially is you use a hose whip if you're working on ramps, or jack stands. In all fairness I'm a lot better versed on the use of an airless sprayer vs. a rustproofing gun. Which is why I favor the method I mentioned.
I have one more vehicle to shoot and I might experiment a bit with thinning the product more and different air and fan settings of my rustproofing gun, which might change my POV on application methods.