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Surface Preparation Needed for Paint Scratch Touch-Up?

 

SITUATION: Our customer's GPS antennas have been operating on FAA facility rooftops all over the USA since 1998. We're bringing them back from the field for internal upgrades, then touching up paint scratches on their lower housings prior to their return. The housings are made of aluminum alloy 6061-T6, .125 thickness, then chem filmed (yellow per MIL-C-5541, CL 1A), then painted with white paint (polyurethane enamel cardinal white, 6409-10 with UV additive). We plan to use Testors paint marker #2545C for the touch-up.

QUESTION 1: Should we touch-up (brush on) the scratches with Alodine 1201 ⇦ this on eBay or Amazon [affil links] (or equivalent) prior to doing the paint touch-up? Not sure if it's acceptable to merely add paint to scratched surfaces that may have bare metal exposed.

QUESTION 2: Any recommendations for how to "feather" the scratched areas without damaging the chromate conversion coating?

Randy Van Steen
- Fullerton, California, USA

Try contacting Henkel Surface Technologies. They produce a chrome conversion coating touch-up marker pen that is MIL-C approved.

Will Rimmer
- Buckinghamshire, England

I would recommend feathering the scratches with Scotch-Brite or equivalent prior to brush Alodine or Touch-N-Prep Pen (Henkel product). The Scotch-brite treatment will help clean the area and the CCC will better adhere to the area.

Ryan Anderson
Aerospace R + O - Mount Uniacke, Nova Scotia, Canada