The Stovebolt Site Forums The Shop Area Paint and Body Shop Metal Prep

Hey Guys,

When sanding down to bare metal, is it recommended to use the metal prep phosphoric acid treatment? If I do this can I use epoxy primer on top of this? I read in another post that you should not do this because the acid will leach through the epoxy. When I have used the Por-15 I have used the metal prep before applying the paint.
It seems that sometimes it is almost impossible to get the surface 100% clean with out some small rust pits or scratches. how do I prep the metal to have a super clean new metal surface?

thanks,
skipper

All major paint manufacturers sell a product like this. They all recommend washing off the product. You can trust wikiwhatever or the manufacturer.
This guy decided to test the idea on his own.
Now you can decide for yourself.

You tell 'em CASO!!!! I don't have the time nor inclination
to get into a pizzin' contest today1!!
dg

Lacquer paint ain't Epoxy Denny. Don't confuse people with Apples and Oranges comparisons. That's just throwing mud at a window to help visibility

Here is PPG's own product sheet telling how THEY want it done.

You'll please notice that while they say in Step 2 (DX520) you can "rinse well and dry" in Step 1 they want the First product (DX579) applied with a scuff pad over an already cleaned (rust etc.) surface, then while it is still wet (notice no mention of letting the DX579 dry before the DX50) the next step begins.

Their product is just another formula of phosphoric and other acids and wetting agents similar to Ospho or Metal Prep.

I read it as scrubbing only Galvanized or Gavaneal metal which I didn't think that rc356s was asking about. Am I interpreting this wrong?

You're correct Drew the 'pad' speaks to galvanized or galvanneal. The products are both washed off while the acid/'product' is still active/wet just the same.

Above the chart under "Application" they also say that the surface should be "abraded" and "all contaminants" removed before applying the product.
That would either be a solvent based grease remover as well as a water soluble wax and grease remover, or at least a 'hot' soapy water and rinse in my understanding of removal of 'contaminants'.