by Bob Beranek

I recently replaced the windshield on a new Infiniti QX56 and I was able to peel the urethane away from the pinchweld with only my hands and no stripping tools. This is nothing new, but it is disconcerting. I remember the first paint delamination (PD) occurring in the mid 80’s just about the time lead was removed from the paints and the frits.  It was a big deal then, and those of us in the aftermarket industry were very concerned with improper paint application, considering that the windshield was a safety device.

The truth of the matter is that even today, not all new vehicles or models are crash tested. Even if a new model is tested, manufacturers will check only one in a series. The results are then recorded for review if the government requests it. As regulations go, this method of testing is not unusual.  It is expensive to crash vehicles and it is not practical to crash every year, make and model of every color vehicle. Therefore we, as auto glass technicians, must recognize the problem and fix it to the best of our ability as professionals. What is paint delamination? How do we fix paint delamination?

What is paint delamination? It is the separation of one coating from another. It can be the separation of the clear coat from the color coat that shows itself on the urethane bead as a glossy film. It can be the separation of the color coat from the primer coat that shows itself as the color of the vehicle coming off with the urethane bead. I have never seen the primer coat separating from the “E” coat nor the “E” coat from the bare metal but I have seen plenty of the other instances on many different years, makes, and models.  Paint delamination does not always occur around the entire perimeter nor does it show itself only in a particular area of the pinchweld, though, there is usually a failure in the lower corners near the body seams.

Manufacturers are reluctant to admit there is a problem so it falls to us to correct it the best way we can. We must use the knowledge we have of the technology of adhesives and plain old common sense to apply a fix.

Many years ago when this problem first showed up I noticed that one of my friend’s vehicles showed paint delamination. I asked him if I could do a test. He agreed, so I replaced the glass with my “PD fix” and then came back several weeks later to check out the results. What I found is that once I removed the glass and checked the urethane bead I noticed that the bead was strong and securely bonded to the area that failed before. The fix was stronger than the original, so I use this method of repair every time I see a “delam” on the pinchweld.

How do we fix paint delamination? Here are the steps I take to correct the paint delamination I find.

  1. Lightly abrade the area with a plastic abrasive pad (Scotch-Brite™) or stainless steel wire brush. Do not go down to bare metal. The purpose of the abrasion is to create a larger bonding surface by causing grooves in the primer coat.
  2. Take a damp, not wet, clean lint free paper towel and wipe the area of any debris and dust created by the abrasion. Allow the area to dry thoroughly.
  3. Primer the area with a thick coating of pinchweld/metal primer and overlap onto any existing urethane by 1/8 to 1/4 inch. Do not puddle the primer. Make it thick and black.  Allow the primer to dry the recommended time for adhesion.
  4. Apply the urethane bead as normal.

I would love to hear from anyone out there that has another fix for this problem. Please respond or give me a call.

Comments (4)

  1. Daniel said on 08-11-2012

    Hello, everybody

    We also noticed this problem, sometimes dealing with young vehicles.
    we noticed that the urethane bead was peeling out with the lack protection layed onto the paint, as colour remained onto the pinchweld.
    I suppose the time allowed for the complete curing of the paint is limited due to mass car body production method, and the bond of the robot-disposed adhesive is jeopardized by the incomplete polymerization of the final lack protection.
    As you teach us, the method using a firm strong layer of primer proved to be a reliable solution and I join the team that practice this procedure.
    As a matter of fact, we had such situations involving beemers and VWs manufactured in 2010-2012 !!!

  2. Daniel said on 08-11-2012

    Best wishes from Dr. Windshield of Romania, now located @ Der Lack Doktor – Tegen 6, Berlin !!!

  3. said on 09-11-2012

    Considering the push by the OEM’s to move to primerless bonding systems to save a buck, I think there is more risk not than there used to be. It started in Germany, and is working it’s way to the U.S. market.

  4. Phil said on 09-11-2012

    The methods for repairing this condition can be adhesive manufacturer-specific. All of these steps would be recommended by any of them but there may be other additional steps required by your adhesive manufacturer. Some recommend removing ALL of the color coat that remains, some recommend an additional primer before or after the black pinchweld primer.

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