Quote:
Originally Posted by Ironangel
Phosphoric acid is the "active ingredient" in most all "rust converters"...I bought a gallon of the stuff at The Home Depot years ago along with an inexpensive plastic 1-gallon sprayer. Spray the rusted areas with the Phosphoric Acid solution and allow it to dry. The rusted areas should turn into a hard black crusty surface compound. Hence the term "converter" as the rust, (iron oxide) absorbs the phosphorus from the solution to create an inert compound known as "iron phosphate"...Pink Navel Jelly is glorified phosphoric acid in a pretty pink jelly...Do your research. Epoxy coatings are only good after a converter has been used first otherwise the rusting process will continue underneath the coating. The same is true for powder coatings as well. Unless the rusting (oxidation) process is stopped either chemically (by converting it into an inert compound) or physically (by grinding away completely) the rusting will continue.
|
I've been suggesting P-acid from the home store for years but no one responds. That said, unless you soak something in it (or continually spray), it just turns the surface rust black. Sand on it and you'll find the rust underneath.
The same concept is true of all other rust treatments.
Acid dips and the opposite PH I can't spell seep into lap welds and leach out months/years later, or so I read, destroying the paint. If you dip something, then you need to also dip to apply a coating to inhibit rust. Sadly the first dip leaves a residue that not much will stick to, or so I've read.
Waxy undercoatings are similar in will they adhere to a dirty rusty surface?
All bodies are made with lap joints where rust hides regardless of the rust removal method. We all just have to decide where the rust removal ends. Are we going to grind the welds off a seemingly good door to remove the skin and reskin to make sure there's no rust?
On 67-72 GM trucks, the drip rails have seam sealer that cracked over time, allowing water to seap in at the joints. The seam sealer needs to get dug out, the area blasted, and everything possible to treat and seal the A-pillar. What everything possible means is up to the OP. My truck has the same problem, not to mention rotted inner and outers, and cab corners, lol.