So I used some Ospho rust treatment...do I have a problem now?

[DC932]

So I used some Ospho rust treatment, and left it overnight to see how it reacts since I had never used it before. The next morning, I re-applied Ospho over the area to reactivate it, scrubbed with a red pad, then rinsed everything off with lots of clean water before the Ospho dried and wiped the entire panel dry.

However, I noticed that in the rust pits, the black areas (where the Oshpo had worked) stayed black even after reapplying Ospho and scrubbing. I couldn't scrub the black completely out. Is this a problem or can I assume the acid is neutralized since I reapplied and rinced with water?

Any insight from more experienced users would be greatly appreciated.

 

[chevman]

A black spot would be rust that has been attacked by Opho but not removed, they say the blacks areas are "converted" but I don't use acid to convert rust, I use it to remove rust. Whether or not painting over converted rust is a quality repair is the question. Personally, I don't want to find out.

If its a small part I let it soak until they are gone, on a larger panel I use a small pick to scratch it back and forth and keep brushing on more acid. The acid doesn't loosen the rust to make it fall off, it desolves rust, so the more surface area you expose the quicker it will work.

Keep in mind that the Ospho didn't work all night, it dries fairly quickly