Epoxy primer over treated panels

[AEW]

Hi, Last summer I finished cleaning up some TR3 fenders and body panels to bare metal. To keep them from rusting while I worked on them I sprayed them with zinc phosphate solution from Eastwood. It works OK and all the metal is a gray color now with yellowish streaks, and a little surface powder. I want to paint the panels and tub with two part primer from HOK. All I can get from House of Kolor is a data sheet on the net. They don't respond to email (several tries over past months). The data sheet has cautions about surface prep, but I can't tell whether it relates to rust treatments. The paint store guy says to scuff it up and paint away. I need some more assurance. How have you folks resolved this issue?

 

[Grantura_MKI]

I have the last of the TC bonnet to finish. It was Z/P and looks the same as your bits. Brillo pad and spray a PPG DP series primer. Do not sand trought the DP primer and you will be fine. DP comes in different colours from white to black. Seal the panels before top coating.

 

[AEW]

Thanks, I think I understand your point... If DP is an etching primer it is designed to work in low pH range? If I don't cut through it the next paint layer won't be exposed to any residue (if there is any)?

 

[Brinkerhoff]

I'm not aware that DP 401 is an etching primer, I've used it for close to 15 yrs. now. With what you've used to clean the metal with ( I can see it in the pictures) You probably would be well advised to reclean with a specific "metal prep" for bare steel. That's probably what the Eastwood product is . Get the panel wet and scrub with a purple 3M Scothbrite pad to take the yellow stains off and reclean the metal. When clean , wash with plenty of clear water to remove chemical residue. Dry with paper towels and compressed air. When completly dry then spray DP401 epoxy primer wet so you have a nice heavy single coat on it. The nice part about using the DP 401 is that you have a 7 day window to apply filler and primer surfacer without having to sand. I wait at least one day though so the solvents flash. You don't want to spray metal prep on bare metal and let it dry like you did. Clean it off properly and prime it correctly ( slow reducer and thin so it sprays out wet and covers well in two passes). You'll never have adhesion problems. If you wait outside of the 7 day window , you have to scuff the DP and re apply DP so it eats in to itself. Kevin

 

[Grantura_MKI]

Kevin is correct...Dp is NOT an eching primer. I use DuPont CF22860s for etching. I am not a big fan of wetting a panel, especially in the winter time but everyone has there own methods that work for them. Visit your paint supplier and they will give you a spec sheet on the DP primers and any other product you might want to use. Most of all BE sure that all of the products work togather with your top coat.
I would stay away from a product labeled NCP.

 

[AEW]

Darn, it looks like I've got problems. More than one unfortunately. Some real, some just me? Thanks for your advice on PPG primers.

I think I will need to wait for better weather to do any more washing. Nothing around here will dry for months. The temp in my shed is only 51F, can't paint in the garage (61F) or the boss (wife) will kill me.

I need to neutralize treated panels with seams and welds that I apparently can't do with baking soda and water if I want paint to stick (PPG data sheet caution). Not sure if Metal Prep or Marine Clean actually neutralize things (because Eastwood and POR-15 won't tell me). Also read on somebody's web page that I can't use acetone to wash panels (but I probably could use it as a reducer in the epoxy according to the can?).

I would like to try the DP-401 product, but I already have the HOK non-chromate epoxy primer. (and because the order was placed wrong I ended up with 3 gallons of it.) I wish they would tell me if it would stick to a zinc phosphate treated surface, (but they won't, liability issues I guess).

Oh well. One problem at a time... where does she hide the bullets....

 

[Grantura_MKI]

I think that you have a handle on this. Do one small panel first just to be sure, once the weather turns good for you.
I would stay away from acetone if at all possible...really bad stuff.