Mysterious Issue Is Causing Paint To Peel Off Of Airbus A35o's

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
17,040
Location
Memphis, TN
When I was at my old regional, they were buying new CRJs. Two had the whole side of paint blow off during a test flight. Back down to primer. They sent the guy in charge of that to the factory to investigate. One side of the plane painted by one person; the other had someone else. One side followed the instructions for the paint. The other side, the guy mixed it like he wanted. When our guy confronted him, he mixed up a batch in front of him like he wanted and said he could do it how he wanted and there was nothing they could do. Somehow there was some “protection “ that allowed it. He probably didn’t paint everyone of ours, but some would end up with strange peeling sometimes within the first year.
 

FinnFlyer

Well-Known Member
Joined
Nov 19, 2019
Messages
107
Location
Bell, FL
Someone on the Van's RV forum referenced that paper regarding paint bubbling above gas tank rivets. A mysterious phenomena that's affected both home built and factory built tanks. I don't know if it has been determined at what interface it occurs (rivet surface/primer or primer/paint) or if it's indeed the same phenomena.

Finn
 

Kyle Boatright

Well-Known Member
Joined
Nov 11, 2012
Messages
1,440
Location
Marietta, GA
Looking at the picture from the MSN article, it looks like whatever filler was used over the metal mesh released and the paint came off with it. Did differential expansion rates cause enough movement to shear off the filler? Did the filler have a poor bond with the mesh and underlying structure?
 

AeroER

Well-Known Member
Joined
Oct 6, 2021
Messages
301
When I was at my old regional, they were buying new CRJs. Two had the whole side of paint blow off during a test flight. Back down to primer. They sent the guy in charge of that to the factory to investigate. One side of the plane painted by one person; the other had someone else. One side followed the instructions for the paint. The other side, the guy mixed it like he wanted. When our guy confronted him, he mixed up a batch in front of him like he wanted and said he could do it how he wanted and there was nothing they could do. Somehow there was some “protection “ that allowed it. He probably didn’t paint everyone of ours, but some would end up with strange peeling sometimes within the first year.

This issue will turn out to be caused either by something similar, or something odd and unpredictable such as a nozzle material, air hose lining, unseen mist from a line leak.

We had a persistent contamination that defied everyone for weeks until an office assistant asked about and overhead crane with a tiny slow drip from a visible leak - way up at the top of the shop, who would look up there?
 
Joined
Aug 7, 2019
Messages
275
Location
Harleysville, PA
No mystery here. One of the local mechanics told me it is the "environmentally friendly" paint they are now using.
brings back memories of the Space Shuttle Challenger crash. the insulation of the external tank was changed to an environmentlally friendly chemistry that did not bond as well to the tank or itself and also had tendencies to have voids of unknown size, location, and distribution. An amazing push to develop an ultrasound technique/system that could accurately locate and define them was one of the reasons they were able to manage the risk to some degree when they returned to flight.
 
Joined
Aug 7, 2019
Messages
275
Location
Harleysville, PA
No mystery here. One of the local mechanics told me it is the "environmentally friendly" paint they are now using.
during my decades in the Boeing labs, virtually all of us doing development of the "water borne" coatings saw over and over again how the new "friendlier" systems worked just as well as the older solvent borne systems when everything was perfect. However, the solvent borne systems were quite a bit more tolerant of imperfection in the prep and application processes...and adhesion was more reliable.
 
Joined
Aug 7, 2019
Messages
275
Location
Harleysville, PA
If paint is too thick it can crack like a dry lake bed as it shrinks over time.
another thing we showed in the labs at Boeing was the phenomenon of finish system film cracking "growing" down into the substrate matrix in the laminates.As Pops said, thicker coatings have more forces driving system cracking and all cracks allow foreign elements into the bondline at the structural surface.
 
Top