Accudynetest logo

Products available online direct from the manufacturer

Drawdown Testing: Overview

Drawdown animation
Note: drawdown is shown at accelerated speed.

The drawdown test is a fundamental laboratory technique which is used to evaluate interactions between flat surfaces (such as film, foil, and paper) and a myriad of inks, coatings, paints, suspensions, adhesives, colloids, powders, etc.

Since most coating properties are thickness-dependent, it is imperative that the optimum thickness be determined for each application. Drawdowns allow easy evaluation of wettability, opacity, color match, gloss, tack strength, drying weight, dye uniformity, degree of pigment dispersion, and other attributes. For best results, tests should be performed on a Diversified Drawdown Platform™ or a similar flat surface.

The tools described in this section open up a variety of test options. Even when the drawdown method does not directly emulate a planned production process, it may be a useful pre-production test to screen materials or drying and curing methods.

The following table shows the wet film thicknesses, coverage, and wet film weights that can be produced with our stock metering rods and ACCU COAT Applicators™. Additionally, many alternative coating thicknesses can be produced with special order metering rods. A Universal Blade Applicator can produce any wet film thickness from 0 to 5 mils or 0 to 25 mils, depending on the design chosen and how it is adjusted. Please email or call us for advice on your specific application.

WFT,
mils(1)
WFT,
microns(1)
ft2/gal m2/l pounds/1000 ft2 g/m2 Tool(s)(2)
0.15 3.81 10,700 263 0.78 3.81 A
0.30 7.62 5,350 132 1.56 7.62 A
0.40 10.2 4,010 98.6 2.08 10.2 A
0.50 12.7 3,210 78.9 2.60 12.7 A, B
0.60 15.2 2,680 65.8 3.12 15.2 A
0.70 17.8 2,290 56.4 3.64 17.8 A
0.80 20.3 2,010 49.3 4.16 20.3 A
0.90 22.9 1,780 43.8 4.68 22.9 A
1.0 25.4 1,610 39.5 5.20 25.4 A, B
1.2 30.5 1,340 32.9 6.24 30.5 A
1.5 38.1 1,070 26.3 7.80 38.1 A, B
1.8 45.7 892 21.9 9.36 45.7 A
2.0 50.8 803 19.7 10.4 50.8 A, B
2.2 55.9 730 17.9 11.4 55.9 A
2.4 61.0 669 16.4 12.5 61.0 A
2.5 63.5 642 15.8 13.0 63.5 B
3.0 76.2 535 13.2 15.6 76.2 A, B
3.6 91.4 446 11.0 18.7 91.4 A
3.8 96.5 422 10.4 19.8 96.5 B
4.0 102 401 9.86 20.8 102 B
4.2 107 382 9.39 21.8 107 A, B
4.6 117 349 8.58 23.9 117 B
5.0 127 321 7.89 26.0 127 A, B
6.0 152 268 6.58 31.2 152 B
8.0 203 201 4.93 41.6 203 A, B
9.0 229 178 4.38 46.8 229 B
10.0 254 161 3.95 52.0 254 A
12.0 305 134 3.29 62.4 305 B

Coating weights are based on a coating density of 1 g/cm3 (8.345 lb/gal). To determine dry film weight, multiply table values by percent solids.

(1) Wet film thicknesses are approximate, and will vary slightly depending on coating viscosity, percent solids, and substrate absorptiveness.

(2) A = appropriately sized metering rod; B = appropriately sized ACCU DYNE ApplicatorTM, held at a 45° angle, which applies the maximum possible yield for each coating gate. Holding these applicators at a lower angle will reduce coating thickness down to about half of the maximum value.