Main reason:

1.When spraying, there is excessive pour spout phenomenon.

2.Spray paint cans excessively dump more than 45 degrees cause of more gas and less paint, leading to a reduction in pressure.

3.Spray paint store for a long time more than the expiry date. 

4.The environment temperature is too low to reduce pressure.

Precaution:

1.Using the correct way to shake the paint not to do more inverted spray.

2.Avoid the tilt angle not more than 45°.

3.Avoid using the paint in over expired time.

Correction method:

1.When found out the pressure decreaing, try to use it for once. 

2.With the lack of pressure and low temperatures, it should put the paint into the water of below 50℃ to heat.