Use and Procedure.

Drawdowns are an inexpensive method of making laboratory samples to determine coating thickness, substrate penetration, fluid compatibility, bond strength, etc. Drawdown rods enable the technician to perform these tests with a minimum of effort.

The procedure is as follows:

Drawdown In Use

Drawdown Plate and Rod

Attach (or tape) a sample of the most suitable substrate to the glass surface of the Drawdown Plate. 

Using a spatula, place a small pool of coating liquid near the top of the sample sheet. 

Immediately grasp the ends of the Drawdown Rod. Using the thumbs of both hands to keep the rod from bowing or bending away from the sample, draw the rod down through the liquid pool spreading and metering the fluid across the sample sheet. As the drawdown is made, note the behavior of the coating and any possible reaction with the substrate. (Note: It may be convenient to construct a small trough of cardboard to catch the excess liquid as it is drawn to the bottom edge of the drawdown board.) Immerse rod in Cleaning Tray after use.

The coated sample is now ready for testing. 

If the coating application is too thin, use a rod with a larger diameter wire. Hence, if the coating is too thick, use a rod with a smaller diameter wire.

The wet film thickness shows the wet film thickness that may be obtained from a given wire size. However it is impossible to chart exact film thickness for all coatings since there are so many variables. The wet film thickness is based on 100% solids, no evaporation, no penetration into the substrate. Rod diameter and rod pressure may also affect film thickness. The chart is intended to serve as a guide only in selecting wire size.

JR-I Ordering Info.

JR-II Ordering Info.

Comes complete with

Wire bar coaters

Storage Case