Delamination occurs when 2 layers seperate from each other. This can happen between many different types of material. Delamination can occur between 2 layers of paint, but also between a wax and a coating. Even when windowtint seperates from the window, it can be referred to as delamination.
Whats is delamination
When a certain substance is applied on top of another substance, it is generally intended for these 2 layers to remain attached to each other. The bond between these layers depends on several variables then can differ between types of substance. This bond can be mechanical or chemical. In some cases this bond fails, and different types of energy/force can exert a force greater then the strength of the bond between these substances.
For example; if a wrap is appied to a body panel, the bond between the wrap and the paintwork underneath depends on the chemical bond of the glue on the wrap. If the glue can’t adhere properly to the paintwork surface, the wrap will not “stick” to the bodypanel. Due to tension in the wrap from stretching it, the force of the pull caused by this tension can exert a force greater then the bond between the 2 layers. The result is that the wrap will delaminate.
Another example could be when a bodypanel is reparayed, but badly prepared for the respray. The new layer of paintwork will not bond properly with the old layer of paintwork. Due to stress in the material, the new layer of paint might eventually start to delaminate. This can be seen as patches of paintwork that start to come off.
Delamination of the clear coat is often seen in heavily damaged and/or oxidized paintwork.
What causes delamination
The bond between 2 substances is either mechanical or chemical. Mechanical bonding refers to the use of objects that hold the material in place, such as welding, screws, rivets or clams. Chemical bonding refers to the use of a third substance that acts as a medium to keep the 2 materials together, such as glue. Some substances, such as paint, is applied in a liquid form and during the “curing” process it creates a chemical bond with the material underneath that doesn’t need glue or any other medium to create the bond. This is still a form of chemical bonding.
The bonding, whether chemical or mechanical, is subject to the strength of the bond. If a screw or weld is not strong enough to take the forces exerted onto the material, it will fail and release one or more of the materials. Chemical bonding can also fail when the chemicals have not been succesful in creating a strong bond. This might happen when you try to apply windowtint to a very dirty, or greasy window. The tint will try to bond with the dirt or grease, but not with the glass itself.
Delamination and protection
Delamination is most often mentioned when visual sign of failure are clear. But some delamination can be to subtle and small to be seen with the naked eye. Many protective products can suffer delamination without any visual signs. If the paintwork hasn’t been cleaned properly, a coating might not bond properly with the surface underneath and eventually fail. The only visual signs are that the protection is visually failling (no more beads, sheeting is gone, dirt is more difficult to clean off etc.). This also goes for sealant and waxes. Although wax is generally much less supseptive of faillure due to incorrect prepping of the surface.
The key to prevent delamination is preperation of both surfaces. This generally means that the surface needs to be cleaned properly, and any unwanted particles and/or contamination needs to be removed.
For example, when applying paint to a surface, the surface needs to be free of dust, dirt, grease and any unwanted particles. In many cases, the surface is sanded lightly to increase the size of the surface, so there is more surface to contact with.
In cases of applying coatings or sealants, it is important to clay, polish and wipe down the surface carefully. If the surface is perfectly clean, the protective product will bond much better and the durability of the product will be a lot better. Spending a few hours extra on preparing the surface, might result in several weeks (or months) of extra protection.