VISCOSITY CUP MANUAL

VISCOSITY CUP MANUAL

Consult your specific product manual for guidance. Maybe you’re planning to purchase a sprayer for the first time, or have already purchased one and didn’t realize you needed to measure the viscosity. If you own a sprayer already, consult the manufacturer’s details and note the desired viscosity range. Pay particular attention to the last number, which will tell you how many millimeters the opening should be. Take a look at the labels of any finish you are currently storing, and note which type of viscosity cup is mentioned.

Decide what kinds of viscosity cups you need.

Thus, if your paint sprayer asks for paint with a viscosity of 15-30, Zahn #4, this would refer to paint that takes between 15 and 30 seconds to pass through a Zahn-type viscosity cup with a four millimeter opening at the bottom. Viscosity measurements are listed as following: number of seconds that the fluid flows, the type of cup and the size of the bottom opening, measured in millimeters. ISO, AFNOR, and ASTM cups are other well-known types of cup. The two biggest names in the game are Zahn and Ford.

Get to know the most common viscosity cups.

While cheaper versions of viscosity cups are available, you can also make your own. This level of precision is not necessary for working with paint, stain, and wood finishes. Highly precise viscosity cups used for scientific purposes can cost close to $300. More than 20 different versions of viscosity cups are available on the market today. Popular models are Zahn and Ford, but many, many others exist, making things even more complicated.Ĭonversion charts are used to help you understand how the measurement on the label will correspond to the measurements of other viscosity cups. Learn more about what an HVLP sprayer is, and why viscosity is an important measurement. When you purchase a paint sprayer, the label will likely list a desired range of viscosity, as measured by a specific type of viscosity cup.

When they get up to room temperature or are left in the sun, the viscosity will lower. Paint from cans stored on a concrete floor, for instance, will be more viscous than the same paint from a can stored on the shelf. The viscosity will change based on storage methods, ingredients, age, and environmental conditions. Viscosity cups solve this problem by giving you a way to measure the actual viscosity of your substance in real time. What works on a cool, dry day is different from what works in warm, wet weather. Unfortunately, you can’t just find a ratio of product to thinner that works once, and stick with it for the rest of your woodworking life. In order to apply one of these products with a sprayer, for instance, you must thin it to a viscosity that will easily travel through the hose, nozzle, and spray tip, without clogging. It is essential when applying these materials with a spraying device. Knowing the viscosity of your paint, stain, or wood finish is helpful anytime you’re operating outside of the ideal temperature conditions.

To find out exactly how viscous a substance is, use a viscosity cup. High internal friction makes the molecules harder to separate, resulting in slower pour times than water, and more difficulty spreading the material. Household paint, on the other hand, can be highly viscous. Water has low internal friction, and therefore, low viscosity. Water molecules easily slip past each other, making it easy to pour or spread. It describes how much internal friction there is at a molecular level. Viscosity, simply put, is a measurement of how much or how little a given fluid ‘flows’.