The Pfund Wet Film Thickness Gauge consists of a spherical convex surface which is forced through the wet paint layer. An oversized circular paint spot is formed on the glass lens, corresponding to the sum of the thicknesses of both the original undisturbed paint film and the displaced paint film that wets the glass.
Features
Technical Attributes
Diameter of Spot (mm) | (mm) | (mils) | S. R. (sq. ft. per gal.) |
3 | .00225 | 0.089 | 18,088 |
4 | .00400 | 0.157 | 10,175 |
5 | .00625 | 0.246 | 6,512 |
6 | .00900 | 0.354 | 4,522 |
7 | .01225 | 0.483 | 3,321 |
8 | .01600 | 0.630 | 2,543 |
9 | .02025 | 0.797 | 2,009 |
10 | .02500 | 0.984 | 1,628 |
11 | .03025 | 1.182 | 1,345 |
12 | .03600 | 1.418 | 1,130 |
13 | .04225 | 1.660 | 963 |
14 | .04900 | 1.930 | 830 |
15 | .05625 | 2.214 | 723 |
16 | .06400 | 2.520 | 636 |
17 | .07225 | 2.850 | 563 |
18 | .08100 | 3.185 | 502 |
19 | .09025 | 3.550 | 460 |
20 | .10000 | 3.937 | 407 |
21 | .11025 | 4.34 | 369 |
22 | .12100 | 4.75 | 336 |
23 | .13225 | 5.21 | 307 |
24 | .14400 | 5.67 | 282 |
25 | .15625 | 6.15 | 260 |
26 | .16900 | 6.66 | 241 |
27 | .18225 | 7.16 | 223 |
28 | .19600 | 7.71 | 207 |
29 | .21025 | 8.28 | 193 |
30 | .22500 | 8.85 | 180 |
32 | .25600 | 10.04 | 158 |
34 | .28900 | 11.38 | 141 |
36 | .32400 | 12.75 | 125 |
38 | .36100 | 14.21 | 113 |
Standards
ASTM D1212
Procedure
The general plan of the Pfund Paint Film Gauge is shown in the diagram. A convex Lens whose lower surface has a radius of curvature of 250 mm is mounted in a short which slides freely in an outer notched. The compression springs keep the convex surface out of contact with the wet paint film until pressure is applied to the top.