Paint and Refinishing – B.6 Surface Preparation – Featheredging – Part 4

ASE Task – Featheredge areas to be refinished. HP-I

What Is Featheredge

Featheredging is the process of layering each layer of coating making a level surface from the substrate to the top surface. It is kind of like stars compared to a ramp going to a building. The stair are steep and with a noticeable difference in height between each step. A ramp made for wheelchairs gradually goes from the ground to the top level with a much smoother transition. This is generally going to take a longer path to reduce the ramp being as steep as the stairs.

Feathering paint is the same process. We need to take the hard paint edge and layer each coating at least ¼ inch to produce the smooth transition. So a small chip or scratch is going to be a big area when featheredged.

Areas That Need Featheredged

If you remove the coatings to perform bodywork you will need to featheredge the paint edges. Also if there are any scratches from sanding, or if the car was scratched during an accident or keyed, the area will need to be featheredged to level and provide that smooth transition from the substrate (bottom of scratch) to the top surface (clear coat). This may require several layers of coating to feather. For example, you may have e-coat, primer, basecoat, and clearcoat. Each coating should be layered ¼ inch. Another problem that may require featheredging are rock chips. Rock chips follow the same concept of providing a smooth transition from the top surface to the bottom of the rock chip.

How To Featheredge

Featheredging is performed using a DA sander. 220 grit is the most common sandpaper used for this. When using a DA sander, do not use the interface pad. Remember in the video over final sanding, the interface pad follows the contours of the surface. If the interface pad it following the contour of the paint edge, then it’s going to make it difficult to layer the coatings. So a harder surface is going to work better. Therefore, use the DA sander and sandpaper is all that is needed. Featheredging can also be performed block sanding the surface with 220 grit. This is going to take more effort and time, but t can be done.

What Problems Can Improper Featheredging Cause

If the surface was not feathered enough you risk seeing rings in the surface after the part has been painted. You may even see multiple rings where the different layers were feathered. To eliminate this be sure to sand each layer at least ¼ inch. It is also a good idea to primer and block sand any areas that were featheredged. By properly featheredging, priming, and blocking, the area will not be noticeable after the vehicle has been painted and clear coated.

Example Questions

1. Technician A says feather edging may be used to sand rock chips.

Technician B says an interface pad should always be used while feather edging.

Who is right?

Technician A

Technician B

Both A and B

Neither A or B

 

2. Technician A says 220 grit may be used for feather edging.

Technician B says each coating should be feathered at least 1/4 inch.

Who is right?

Technician A

Technician B

Both A and B

Neither A or B