Ask the Expert Question-and-Answer Archive

by Ron Joseph

July, 2003

Measuring Viscosity of Coatings

Q. Could you please tell me if there is a way to convert viscosity reading from centipoise in CPS to that obtained from a Zahn cup #2 in seconds?. I want to compare two readings that have been made using different measuring instruments.

A. I'm not aware of any calculations that will allow you to convert viscosity readings in CP to Zahn #2 cup values. I do know that the vendors of viscosity cups have conversion tables or charts that give you an indication of how the two values compare.

Since not all fluids are Newtonian, I would guess (but I don't know this to be a fact) that it is not possible to calculate the viscosities across different measuring methods. (For instance, viscosity measured by means of a Zahn cup is different from that measured by a Brookfield.)