1, measure cylinder method: add a suitable amount of low viscosity coating in the measuring cylinder, add defoamer, shake it and observe the height of foam every once in a while.          
2. High speed stirring method: it is suitable for low viscosity coatings, and the foam level is measured after high speed mixing.          
3, gravity cup method: suitable for high viscosity coatings, paint and defoamer together to homogenizer high-speed mixing, and then determine the height and density of foam.           
4、 Circulation method: after coating, the remaining coating will fall into the container, and the height of the coating shall be recorded at intervals.         5, bubbling method: suitable for low viscosity coatings, air will be introduced into the paint to produce foam, add defoamer regularly after the export of air, and timely recording the height of foam.         
6, vibration method: repeated vibration, and then foam density measurement.
The above is the six test methods of defoamerfor coating, hoping to help you.