Depainting critical during C130's PDM, allows mechanics to inspect surfaces for cracks, corrosion and damage

  • Published
  • By Jenny Gordon
  • Robins Public Affairs

About this series

Over the next several months, Robins Public Affairs will document the programmed depot maintenance of a C-130H during its time at the Warner Robins Air Logistics Complex. The Rev-Up will highlight various stages of the PDM process, telling the stories of the people and organizations who make the mission happen here every day.

Even a tactical airlifter like a C-130H needs a fresh scrub and wash to feel like it's shiny and new again. It's been more than a month since the aircraft we've been following made its August debut on the Robins flight line, where it completed induction and disassembly for de-paint operations in Gate 1.

Each stop that it makes inside a gate - there is a seven-gate structure - moves it one step forward. It's part of an incredible production machine at the Warner Robins Air Logistics Complex that works nonstop, 24 hours a day, seven days a week.

The second gate, or process, recently completed, included the removal of the aircraft's former paint job. 

This point is critical during an aircraft's programmed depot maintenance because removing paint allows mechanics at a later stage to thoroughly inspect surfaces for any cracks, corrosion and other potential damage. 

Depending on where it is in its maintenance cycle, some C-130s come in for just a scuff sanding overcoat process, where surfaces are sanded and recoated. That happens every five years. In this case, this C-130H is being completely stripped of paint for inspection purposes, which occurs every 10 years. 

Once certain aircraft parts were removed, such as its flight controls, wheel well doors and aft engine nacelles, it was towed into Bldg. 54 to prep for de-paint procedures. 

The Maintenance Support Squadron's Corrosion Flight was at work in mid-September, completing the process in less than a week.

"With everything associated during this process, we have continued to improve to make our procedures as safe as possible," said James Cranford, Corrosion Control Flight chief. 

It took a few days to remove the paint using a hydrogen peroxide/benzyl alcohol-based paint stripper - a chemical that basically loosens paint. 

But first thing's first.

Before chemicals can be used, certain areas of the aircraft must be covered up to prevent chemical intrusion. That's where painters pull out lots of aluminum tape - the silver lining if you will- to mask the radome, windows, and wheel wells, etc.  

Then several painters suit up in personal protective equipment, which includes a special heavy-duty rain suit, steel toe boots, shin guards, rubber gloves and full-face respirator. 

The chemical paint stripper is then applied to remove primer and paint. If there are stubborn spots, it's removed toward the end of the process using an Aqua Miser, a high-pressure sprayer that blasts out water at about 24,000 pounds per square inch. In other words, it's pretty powerful.

Ronnie Harrell, who has worked at Robins nearly 27 years - mostly in C-130s - has seen many changes.

"During my time I've seen much improvement as far as chemicals we've used," he said. "What we're using now works better than what we've had in the past, and it's safer for our workforce and environment."

Paint from a C-130 can sometimes be harder to remove than others.

"Depending on the age of the paint or where an aircraft is from, it can vary how easily paint comes off," said Troy Harmon, Corrosion Flight supervisor.

"This one here was pretty clean. I'm proud of it," he said, referring to the aircraft in this series. "The foundation of a good paint job is a good de-paint job. The cleaner we get it, the easier it will be at another stage when it's painted."            

Interestingly, just as this particular C-130H was having a few paint spots removed, a second C-130H was a few buildings over, bound for the same location overseas. It had just received its own new coat of paint and was awaiting final delivery.

Diligently removing paint at this point sets it up for success later when it's time for a new coat. 

"We try to do things during the stripping process that will enhance the paint process," said Cranford."While our processes are really about corrosion prevention, you better believe that cosmetics play just as important a role to the home station when we send an airplane back. The first thing they look at is appearance. That's Robins' first opportunity to provide a quality product, and it's the first impression we give."  

"You only get one first impression so we do our best to make it positive," he said. "It's all part of our commitment to the warfighter to provide a quality product that will be reliable and low maintenance until its next visit to the depot."