Metal Prep, Phosphoric Acid

The DuPont metal treatment system (phosphoric acid type) actually consists of two steps: 5717S, metal conditioner, followed by 5718S, conversion coating. You may notice what appears to be some flash rusting after rinsing following 5717S. Not to worry, the 5718S will take of it.

The process goes like this: Apply 5717S diluted as instructed, scrub with a scotchbrite pad, rinse with water, apply 5718S undiluted, scrub with a scotchbrite pad, final rinse with water. Then prime using your epoxy primer.

I would recommend NOT doing the phosphoric prep until you are ready to prime. I would do it immediately before priming. I would not worry about some minor rusting taking place before treating with 5717S. That step will remove minor surface rusting in the scrubbing stage.

For DuPont technical data sheets on the process for each product, go to the link below and scroll down to 5717S and 5718S. Download both pdf files and they will explain it far better than the label instructions.

Rod

• DuPont ChromaSystem Technical Data Sheets

1. To login, click on "visitor" button
2. Click on "products" button in upper right
3. Click on "technical manuals" on the left
4. Click on "ChromaSystem" on the left
5. THEN scroll down to 5717S and 5718S

• DuPont Web Site