Main reason:

1.The injector is too close to the surface.

2.The speed of the injector moving is too slow.

3.The environment has bad ventilation.

4.The interval times is insufficient the same as drying time is not enough on the underlying.

5.The surface gets contamination.

Precaution:

1.The suitable distance between injector and the object should be 20-30 cm.

2.The normal speed should be 30-60 certimeters per second.

3.Keep the environment with good ventilation.

4.According to the environmental temperature, the suitable interval time i to 5-15 minutes for each layer.

5.Ensure the surface must be clean.

Correction method:

1.After a slight sagging completely dry in the room temperature for 16 hours, use the P1500 sandpaper to polish and then use the polish wax.

2.After a serious sagging completely dry, use the P800 sandpaper to polish and spray again.