ltbewr
Posts: 12361
Joined: Thu Jan 29, 2004 1:24 pm

How Are Large Aircraft Repainted-procedures

Fri Jun 11, 2004 8:52 pm

What are the procedures done to repaint a large commercial aircraft (not small, GA aircraft)? How is the surface prepared, is primer used, and other such possible procedures? I would like to see a basic outline of the procedures. I ask this due to a recent post on cracks on some Boeing aircraft, where Boeing put out an advisory to owners. It was suggested by posters that there may have been improper 'shortcuts' in the removal of paint and decals including the use of metal scrapers.
 
UTA_flyinghigh
Posts: 6304
Joined: Wed Oct 03, 2001 8:46 pm

RE: How Are Large Aircraft Repainted-procedures

Fri Jun 11, 2004 9:11 pm

I once had the opportunity of seeing F-GITB being prepared for a paint job; paint is removed by blasting small plastic "marbles" to remove the paint. Certainly not scrapers which could damage the metallic structure.

UTA
Fly to live, live to fly - Air France/KLM Flying Blue Platinum, BMI Diamond Club Gold, Emirates Skywards
 
greasespot
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Joined: Sat Apr 24, 2004 10:48 am

RE: How Are Large Aircraft Repainted-procedures

Sat Jun 12, 2004 12:38 am

A lot of times the new paint is just applied over the old. I have seen many white airplanes with multiple colors underneath

GS
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
 
dl757md
Posts: 1482
Joined: Mon May 24, 2004 9:32 am

RE: How Are Large Aircraft Repainted-procedures

Sat Jun 12, 2004 3:18 am

I can't speak for the rest of the industry but this is how DL does it.

  • The plane is washed to remove dirt, grease, and oil.

  • Taken to the paint hangar where composites, windows, landing gear, engine inlets and exhaust, pitot probes, static ports, etc. are all taped off.

  • Chemical stripper applied and paint removed.

  • Thorough rinse with water.

  • Wet abraded with scothbrite pads on dual action sanders to remove aluminum oxides.

  • Rinsed again and inspected for "break free"(no surface tension break)rinse.

  • Sealant in skin seams is removed and replaced.

  • Painted areas of Aluminum are acid-etched.

  • Painted areas of Aluminum are alodined.

  • Composites are sanded and prepped for paint.

  • Windows, landing gear, engine inlets and exhaust, pitot probes, static ports, etc. have tape removed and fresh tape applied.

  • Painted areas of fuselage are primed with Zinc Chromate primer.

  • Base coat consisting of 2 layers of polyurethane epoxy is applied.

  • Designs, logos, and lettering are painted.

  • Decals and FAA mandatory stencils and placards are applied.

  • Bare aluminum is buffed.


  • In the mean times the wings have been either stripped or sanded. Then painted with aluminized primer(the dull dark gray usually seen on wings) from spar to spar. Gray poly is used on the LE and TE closeout panels, control surfaces and flaps. Teflon paint is used on the wing and control surfaces/flaps where rubbing may occur. Finally the emergency evacuation paths and the FAA mandatory stencils/placards are applied.

    There is more to it than stated above but I hope this answers your question.

    Dl757md
    757 Most beautiful airliner in the sky!
     
    PHLapproach
    Posts: 1052
    Joined: Tue Mar 23, 2004 6:37 am

    RE: How Are Large Aircraft Repainted-procedures

    Sat Jun 12, 2004 7:12 am

    UTA_flyinghigh - it sounds like you saw an aircraft media blasted which is as you described like little marbles. It's more like little pieces of plastic.

    Dl757md - Does DL apply a clear coat later on or is the polyurethane epoxy you use like an SS?

    Ltbewr - yes, as for shortcuts. The same applies to Aircraft refinishing as for automotive finishing/ refinishing. If one prep procedure falls through the cracks and say one person want's to take a "shortcut" within less than a week that paint that was just applied will start lifting or peeling. That can be the cause of not properly washing/ de-greasing/ de-waxing the aircraft or even not sanding or abrading the material to be painted. My friend's dad accidentally banged into something while pulling their 77' Trans Am into the garage so they took it to a really good body shop.It cost them $1000 to get a golf ball sized dent fixed and refinished. Well, when they got it back. Over near the dent the new paint was bubbling and lifting. That was caused by the Painter not wearing gloves (you can contaminate the surface with the oils of your hands) I always make sure to use gloves. See because of that Painters carelessness the paint lifted. That's a great explanation by Dl757md above of all the prep procedures. He said they use Chemical stripper which all companies and manufactures use, it would be just to long otherwise. You can pick it up in any store, It's called KleanStrip or of course Aircraft Remover. HAHA, If your ever mad at anyone just toss that on their car. Just kidding, never do that. That's just harsh.

    [Edited 2004-06-12 00:13:47]
     
    EMBQA
    Posts: 7795
    Joined: Sat Oct 25, 2003 3:52 am

    RE: How Are Large Aircraft Repainted-procedures

    Sat Jun 12, 2004 7:18 am

    As someone that ran my airlines paint line DL757 has it spot on...!!!

    No, a 'Clear coat' is not applied to most all colors. Most of the modern paints do not need them. 'High Soild' Paint when it dries offers a mirror like finsh if applied correctly
    "It's not the size of the dog in the fight, but the size of the fight in the dog"
     
    ltbewr
    Posts: 12361
    Joined: Thu Jan 29, 2004 1:24 pm

    RE: How Are Large Aircraft Repainted-procedures

    Sat Jun 12, 2004 8:47 am

    Dl757md, Thank you for the outline of the process of repainting, I would assume similar procedures are used throughout the industry. I am somewhat familiar with the procedures used with cars (as PHIapproach posted), and assumed correctly that for large aircraft the procedures, as you described Dl757md are much more detailed vs. cars.

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