2k urethane over osphoed metal ?

i Oshpoed some body parts yesterday.
Can I shoot 2k right over that ?

Few years ago I had epoxy blow right off of osphoed body panels & with epoxy manufactures blessing - so epoxy again is kind of scary

 

I'd hit it with Ospho again to reactivate it then rinse it with water first before you spray it.

 

i would spray a small area with the 2k just to be sure. i'm not a big fan of spraying anything on bare metal with a film on it. i'm sure others have had success with it, but i always feel more confident with etch or epoxy direct to clean metal.

 

Isn't Ospho a phosphoric acid based metal prep? (I dont use it)
Many formulations of epoxy tell you not to put it over metal-prepped surfaced, it doesn't like the acid. If you dont feel like experimenting, check the tech sheets of the epoxy you are using

 

The majority of 2k urethane primers are not DTM. More details man ?? what kinda 2k urethane? and yes some epoxies and Phosphoric acid do not play well together.

 

Mar-hyde 2k urethane filler primer (black) by 3m is what I'm using.
Its going on a wiper cowl with 10,000 louvers. 80% of them were surface rusty in the holes and on the bottom side. Ospho took care of the rust perfectly.

Just for background, the epoxy failure several years ago was completely covered by the paint manufacturer , but they never said what it was that caused it. Ospho was thoroughly investigated and discussed before application.

 

The second post has it spot on... that film is still acid based and rewetting (with the ospho) reactivates it and then the H2O neutralizes it. It has to be wet to neutralize though.
Then I give it a quick blow dry with the shop vac and/or let it set an hour and it's ready for the W&G remover.