Inside Look: Aircraft Painting Prep Lays Foundation for Perfect Finish

November 17, 2022

Whether it’s the front door of a home or a VVIP Boeing Business Jet, any experienced painter knows that prep work makes the difference in how a paint job turns out and holds up.

From the first coat stripped from an aircraft to the last coat applied for a colorful design, King Aerospace’s paint team in Ardmore, Oklahoma, has earned a reputation for attention to details – and a commitment to putting in the hard work required at each step. That thoroughness results in top-class paintwork reflecting one of our Cornerstone Principles, quality in everything (no excuses).

Randy Johnson, director of corporate aircraft services, recently described how the labor-intensive stripping, sanding and priming stages lay the foundation for the painting that follows. Now, he leads us through the ensuing stages that bring his team praise from the most discriminating of customers, whether the owner of a BBJ or government officials responsible for aircraft transporting our nation’s leaders.

It takes sacrifice to ensure it gleams

A high-build fill primer does what the name implies – helps fill butt joint and lap seam sealer imperfections, rivet halos and other imperfections in the aircraft’s skin before additional coats of paint go on. We don’t stop there in the hunt for blemishes that can become apparent once a glossy finish goes on.

On a BBJ aircraft, we spray on two coats of white paint – as a sacrificial topcoat that leaves it essentially looking like a well-prepped airliner. This allows paint team members to see any missed dents or identify spots where the composite might have pin holes. Any defect is then smoothed out with sanding and painted again.

A sacrificial topcoat exposes any blemishes in the aircraft’s skin that need addressing.

The real topcoats go on

Next, we take fine sandpaper – 320 grit – to the sacrificial topcoat or fill primer to remove all the texture and gloss of the previous coatings. After the sanding is complete and inspected, we blow off the aircraft and wipe to remove as much dust as possible. Then, as occurred earlier during stripping, areas of the aircraft needing protection – windows, light lenses and so on – are remasked with new clean materials. Then the aircraft is blown off even more. The next step is solvent wiping. We solvent wipe until the surface is extremely clean, then use a tack cloth over all surfaces to be painted before paint application starts.

We then apply three coats of white topcoat, as opposed to the two that most shops do. Another key difference is that each coat is allowed to dry naturally for about 12 hours, instead of using the drying accelerants that, for example, commercial airliners usually receive to limit their time off the flight line. The reason is that speeding the natural drying process results in an orange peel finish, one unlike what customers expect from King Aerospace.

A KaiserAir Boeing 737’s colors included stripes and stenciled flower.

Here comes the color

Painting the stripes and other designs on is the final stage of the painting process. This involves masking off the areas of the white topcoats that will remain unchanged, creating a spray zone for the color.

Before the paint goes on, though, the areas are sanded again with fine grit paper – as opposed to the Scotch-Brite scrub pads some shops use – to ensure any blemishes are removed from where the stripe will be painted. We blow off the aircraft, solvent clean and then use tack cloths to pick up any floating debris. Again, it’s a matter of quality, and quality takes attention to detail.

Finally, the decorative paint goes on. Most of the time two coats will do it, but certain colors, like yellows and some shades of red, require three or four coats to really cover. Some types of paint, like metallics, get a clear coat.

Designs range from simple to complex – all require plenty of taping.

The measure of success

With the glass-like finishes our team produces, customers can see the difference the attention to details delivers. Some customers must put numbers to that quality, using equipment called a wave-scan to measure orange peel and gloss meters to measure gloss and ensure the finish meets the standard.

Our paint team regularly achieves single-digit readings and passes other quality tests, too, like customers poring over finishes with magnifying glasses and putting down and tearing off duct tape to make sure the paint has stuck. The result is a topcoat as good as any in the business, one achieved by not skipping any step, cutting any corner or making any excuses.

There’s another not-so-easily measured factor involved in quality work: our team’s dedication to the mission. That’s something you can readily observe when a painter gets a little choked up as a government VIP aircraft – a high-profile symbol of our nation – rolls away with fresh paint.