Hey everyone,

So here is the poop. Cab completely sandblasted (55 F100), all dents removed, all major rust repaired or replaced (cab corners, rocker panels, driver side cowl, floor, transmission cover, etc...), and ready to lay down some corrosion resistant primer. I chose PPG's NCP 271, recommended by the local auto body supplier, whom I trust.

To clean and condition the metal, I used PPG's DX579 Metal Cleaner/Conditioner. A water based solution you spray on, and then rinse off with a sheeting action. Okay.......now the whole cab looks like it just flash rusted right in front of my eyes.

I looked everywhere on line to see if this what was actually happening. I read in more than one place that the phosphoric acid in the cleaner reacts with metal, leaving a golden brownish coating, which will help the paint adhere.

Has anyone used these products? What has been your process in priming sandblasted metal? I think this is a really important step, since every subsequent coat of primer/topcoat/clear will lay over this initial primer. If this primer were to fail, I would imagine everything on top of it would just flake or peel off as well.

Thanks in advance for any input.

 

Sorry, no help here, I have not used the metal prep from PPG. I did use the PPG Concept products on mine , but did not use the ncp271 or their metal prep. It does make sense tho that when using a water based metal prep, it will instantly make a rust dust on the blasted metal. Water and metal =rust. As you said, the trick now is for someone from the ppg counter to tell what to do with that rust. I have seen the same complaints from the users of the DuPont metal conditioner, so I avoided both the PPG and Duponts metal preps. ...

When I was painting my truck, I stripped the inside of my rusty truck bed, then just used Picklex20 to covert any rust nibs left and leave a bond for the epoxy, shot dplf 40 epoxy on that , shot k38 primer /surfacer wet on wet on the dplf, bc/cc, all are still great today. You do have a very valid concern here. I would think that if a person would rub a gray 3m scuff pad lightly across the metal and rust showed up on it, it would make me nervous about the bonding characteristics of what you are about to shoot your primer on to...

Every pro on the ABS forum where I frequent , will have a different way of coming off of new metal, some etch then epoxy, some epoxy only then primer /surfacer, some epoxy only then reduce their next coat of epoxy as their sealer then they topcoat. Many ways to get where you want I guess. A pros technique will always be the same it seems That is , they use the same products all the time , ones they are used to and trust , and they use the same application technique time after time. That eliminates the re-schooling and learning curves of experimenting with new products too frequently , and yields them the best and long lasting results. all just my two cents tho, good luck to you.