Peter,
Good questions. The simple answer is Corrosion X is for metals that are NOT going to be painted. So electrical connections, circuit boards, relays, battery isolator, hinges and moving parts, battery terminals and bolts and nuts you are trying to loosen are key applications for CorrosionX.
CorrosionX polar bonds to metal molecules vs coating the surface as does oil or dielectric grease. It can not be washed off with soap and water but can be removed with a strong solvent. CorrosionX can NOT be painted over, must be removed before painting.
CorrosionX prevents corrosion by polar bonding to the metal molecule stopping the oxygen molecules in the air from combining with the metal molecules and thereby forming corrosion. CorrosionX is used up over time and will eventually need a new application to keep corrosion prevention in place. It works similar to an anode on a boat which is used up over time sacrificing the anode instead of the boats metal.
How long it lasts is dependent on how aggressive the environment is. So a circuit board on a radio kept inside the coach will be protected for at least two years. The pins and the contact surfaces of my tow bar are exposed to the outdoor environment all the time and get sprayed every 3 months to maintain protection. I do not want to paint the pins and the surfaces that get the paint rubbed off by contact with the car's hitch.
CorrosionX is all synthetic and will not harm the air bags, weatherstripping, gelcoat and other surfaces on the coach.
More detailed info is always available by calling Corrosion X in Dallas.
Ospho is for metals that ARE going to be painted. Prep the surface by wire brushing, sanding and/or wiping clean. Then prime and kill the corrosion by applying Ospho. Once dry, no additional sanding is required, just coat with the paint of your choice for long lasting protection. Since Ospho kills the corrosion at the molecular level, you are not paint coating over any molecules of corrosion that could come back through the paint.
So, clean the metal beams under the coach, prime with Ospho and coat with the paint of your choice.
The rear facing surfaces of my engine and the metal beams in the rear of the coach were corroding. I wanted them to look clean and painted as when new so I did not use CorrosionX. I brushed them off, wiped clean and applied Ospho. I finished with flat black paint on the engine and steel frame members for a clean neat appearance. I could have used CorrosionX and reapplied about every 6 months if I did not want to paint.
Hope this helps you as I sure do like how these two products work for myself.
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