Thanks for the link. The large areas on my truck that I coated with OSPHO several years ago will get hosed and scuffed. I'm really thinking that with the time it's been on and exposed to the humidity (my garage is not climate controlled), there can't still be anything still active and any acidity has long ago been used up. Remember, I said that there is some surface rust starting now. The surface rust is more like the "flash" rust bare metal gets down here in FL when exposed. This alone indicates a level of "inertness" with the OSPHO. I feel confident after a wash/scuff/dry/degreasing, (similar to Barry's advice), I will have no future problems. I did learn one of my co-workers has parts in his garage that he treated over 10 years ago with OSPHO, painted with cheap spray can paint and there is NO sign of "bubbling, blistering, or any sign of peeling--only faded cheap paint. He lives on the Gulf, lots of salty air....

Forgot to add this bit of novice observation, feel free to attack, critique, confirm, deny, etc.
I have NOT heard or read many, if any, posts on this site or others, that refute or deny the super qualities of epoxy primer. It's adhesive qualities to properly prepped and CLEANED bare metal seem uncontested, even by the proponents of OSPHO. If mine were a perfect world, my thought would be to ONLY work on areas of my ride I could in short time apply the epoxy to and then let sit until I could finish and apply paint. I in no way regret using OSPHO for my situation at the time for the INTENDED purpose of delaying the onset of new rust. To this end, I feel qualified to attest to Ospho's success in meeting my needs for literally years beyond my intended time of a few weeks. I understand the debate is about its effect on adhesion of epoxy over it....again to summarize my obersvation, If epoxy needs NO help adhering, why try to give it any? Okay, I'll shut my novice pie-hole now... and get back on the sideline

hwy,
lol,,,
this whole Ospho discussion has more twists and turns and side roads than the Skyline Drive...

yes, leave it on long enough it will go neutral (it reacts with crap in the air like concrete dust or aluminum particles whatever)...

rattle can "air dry cure" acrylic enamel (lacquer thinner solvent based) is NOT a 2 part catalytic reaction epoxy,,,rattle can forms a semi-permeable membrane once cured....

only for the idea:
for rust to grow there must be moisture + oxygen + electric current present...
if the object doesn't stay constantly damp/wet for any length of time each day (due to sun exposure/air circulation/fast dry conditions),,,, and isn't exposed to a electric current or is grounded (FL humidity= about "0" static surface charge),,, then for as long as the binders keep the semi-permeable membrane in good shape,,,,acrylic enamel does do a darn good job for as cheap as it is to prevent rust...

on a car ALL the electricity passes thru the steel (the steel body is the negative volts and amps supply "wire" to all the devices) and the 4 tires means total electric ground isolation,,,and any memory devices like radio presets means current 24/7 thru all the steel....
add our everyday heavy morning dew and showers and there are many areas on a car that don't get much air circulation to dry quick and do trap moisture to raise humidity inside the car = you want the total "barrier" protection of the epoxy,,,nothing is going to pass thru the membrane....
(PS: the 2 part urathane top coat does also have excellent barrier properties so you end up with a belt and suspenders worth of barrier protection)

last rattle can comment?:
I am a long time user/fan of Duplicolor products (love their spray bedliner coating!!),,,,over the years have gotten amazing performance and life out of their van and truck rattle can paints...

lol,,,Brian, if you read this the ten years ago(?) Van and Truck Dup sprayed mail box is still in very good shape both for color and integrity,,,the bird sh## on top is killing that area though...

Thanks for the science in your response Red65. It's good to know the why's of something. Lol about the twists and turns. Looks like no painting epoxy for a week or so...highs only in the low 60's for the next few days..gives me more time to read our Knowledge base articles though.

Hwy,
LOL!!!
get prepared for a total brain overload worth of info on any/all car subjects including paint and body to read!!!!

on this link click on each magazine gives you access to their "how to" and tech articles (including Classic trucks!!!)....

save the link,,,they do add/change articles kind of at random....

(just keep in mind magazines only tell the good half of a story)


http://www.simautomotive.com/oursites.html