Measure what you see.
Pfund Cryptometer
A member of
Manual
Additives & Instruments
BYK-Gardner
Pfund Cryptometer
Manual
English
PA-3301
BYK - Gardner USA
9104 Guilford Road
Columbia, MD 21046
USA
Phone 800-343-7721
301-483-6500
Fax 800-394-8215
301-483-6555
www.byk.com/instruments
BYK-Gardner GmbH
Lausitzer Str. 8
D-82538 Geretsried
Germany
Tel. 0-800-gardner
(0-800-4273637)
+49-8171-3493-0
Fax +49-8171-3493-140
Description
Description
Description
DIRECTIONS FOR DETERMINING WET HIDING POWER BY THE USE OF
THE PFUND CRYPTOMETER
General Remarks: All parts of the instrument – in
particular the clear top plates – must be kept
perfectly clean.
Caution: Do not use solvents to clean the base
plate
While sky-light may be used for illumination in
some cases, articial light – a 100 watt or a 200
watt bulb – has been found to yield the most
reproducible results. Strong illumination should
strike the Cryptometer from the scale side at an
angle of 45°. Allow as little light as possible to
strike the eyes. For best results, conduct all tests
at temperatures between 70° and 80° F.
For a right-handed operator, the Cryptometer
should always be assembled and operated so
that the scale to be read is on the left, the pegs of
the tilted top plate are on the right, and the light
strikes the thin side of the wedge-shaped lm from
the left.
A small amount of thin lubricant, applied to the
outer surfaces of base plate only, where it is
touched by the moving top plate, will prevent
scratches that impair the accuracy of the
instrument.
Stir the paint sample thoroughly so that all
pigments are uniformly distributed. Be careful to
avoid air bubbles. Apply a small pool of paint to
the center of the base plate. If too much paint is
used, there will be an overow into the longitudinal
grooves and nally over the outer strips, which at
all times must be kept free of paint.
Select the top plate with the most appropriate
wedge constant and place it with the pegs down
on the side opposite the illuminated scale. The
number (2, 3, 5 or 7) assigned to a top plate
indicates the increasing slope of the underlying
paint lm. It also corresponds to the actual lm
thickness, in mils, when the touching edge is
set to read 25.4 mm = 1 inch = 1,000 mils on
the engraved scale. This check point should be
marked very near the center of the 0-50 mm
scale where the best precision can be obtained.
It should be used to form a wet lm of known
thickness for selecting the proper top plate and
moving it in the proper directions.
To make a reading, press lightly but evenly on the
four corners of the top plate, move it back and
forth several times to force out all surplus paint,
and then move it slowly to the left until the center
line of demarcation has disappeared completely
over its entire length because of increased wet
lm thickness. Record the scale reading, located
directly under the lower left-hand corner of the
top plate, and call it “disappearance.” After
moving the top plate about 5 mm. further to
the left, reverse the motion while still pressing
down on the four corners as before. Move the
top plate to the right slowly until the center line
of demarcation reappears over its entire length
because of decreased wet lm thickness. Record
the reading as before, and call it “appearance.”
The average of 5 such pairs of readings will
provide a practical mean for the Cryptometer
setting corresponding to visual hiding. Rest the
eyes by looking at a dull black surface (such as
black felt) or by closing them for a minute, and
32
Description
Description
then conrm visual hiding of the paint sample at
the average setting. The number of square feet of
surface area visually hidden by one gallon of paint
is quickly determined by reference to Table 1 on
Page 2. The corresponding thickness of wet paint
in mils (1 mil = 0.001 inch) can also be determined
from Table 1. For Example: If a No. 7 top plate with
a wedge constant of 0.007 results in an average
Cryptometer setting of 27mm, then the wet paint
will hide visually at the rate of 215 square feet per
gallon, and the wet lm thickness will be 7.44 mils.
This target lm thickness can be controlled by
checking it periodically with the Pfund Film Gauge
to assure uniform wet hiding.
DIRECTIONS FOR SELECTING TOP PLATES
A top plate is identied by a number from 1-9 that
is equal to the thickness, in mils, formed by the
wedge over the central line when the Cryptometer
is set at 1.000 inch = 1,000 mils = 25.4 millimeters.
The wedge constant is therefore numerically equal
to the slope of the top plate caused by the length
of its protruding pegs. These pegs can become
worn down by prolonged use over abrasive
pigments, or otherwise damaged. When ordering
extra top plates, be sure to specify the correct
wedge constant that is desired, and also the
model of Cryptometer with which it is to be used.
The three standard top plates are now identied
as follows:
No. 2 with Wedge Constant K = 0.002
No. 3.5 with Wedge Constant K = 0.0035
No. 7 with Wedge Constant K = 0.007
Other top plates with other wedge constants are
available on special order
DIRECTIONS FOR BLACK-AND-WHITE CRYPTOMETER
This all-purpose model is applicable not only to
black and white paints, but to paints of all colors.
It is furnished with Top Plate No. 2 for darker
paints and Top Plate No. 7 for lighter paints. In
case of doubt, it is advisable to use the top plate
which results in a setting nearest to 25.4 mm. on
one of the scales. In using the Black-and-White
model with Top Plate No.2 for black or near-black
paints, it is important to use an intense, constant
and reproducible articial source of illumination. A
200-watt lamp is recommended.
To obtain reproducible readings for colored paints
the following steps should be taken in order:
(1) Follow carefully the instructions given under
“General Remarks” on Page 1
(2) Place the Cryptometer so that the black eld is to
the left, apply a small pool of paint at the dividing
line between the black and white elds, lay the top
plate on it so that the pegs are to the right, an
make 5 pairs of readings for “disappearance” and
“appearance.”
(3) Reverse the Cryptometer so that the white eld is
to the left, and proceed as before to make 5 pairs
of readings
(4) Average the 5 quadruple sets of readings –
disappearance and appearance over both black
and white elds – to obtain a practical mean
setting that can be conrmed for visual hiding
after resting the eyes
(5) Refer to Table 1, under the column heading for the
top plate used, to obtain the corresponding Wet
Hiding Power in square feet per gallon or square
meter per liter and also the corresponding Wet
Film Thickness in mils or thousandths of an inch
or microns.
54
Operation
TABLE 1. WET HIDING POWER AND WET FILM THICKNESS
Cryptometer
Setting
Hiding Power Thickness
No. 2 Top Plate
K = 0.002
Operation
24 20,776 848 48,006 1,89
25 19,943 814 50,038 1,97
26 19,1835 783 52,07 2,05
(mm) ( M²/L) ( ft.²/gal.) (microns) (mils)
1 510,825 20.850 2,0066 0,079
2 249,2875 10.175 4,0132 0,158
3 166,11 6.780 5,9944 0,236
4 124,46 5.080 8,001 0,315
5 99,715 4.070 10,0076 0,394
6 83,104 3.392 11,9888 0,472
7 71,2215 2.907 14,0208 0,552
8 62,328 2.544 16,002 0,63
9 55,3945 2.261 17,9832 0,708
10 49,8575 2.035 20,0152 0,788
11 45,325 1.850 22,0218 0,867
12 41,552 1.696 24,0284 0,946
13 38,3425 1.565 26,0096 1,024
14 35,623 1.454 28,0416 1,104
15 33,2465 1.357 30,0228 1,182
16 31,164 1.272 32,004 1,26
27 18,473 754 54,102 2,13
28 17,8115 727 56,0832 2,208
29 17,199 702 58,039 2,285
30 16,611 678 60,071 2,365
31 16,0965 657 62,0268 2,442
32 15,582 636 64,0588 2,522
33 15,1165 617 66,04 2,6
34 14,651 598 68,072 2,68
35 14,2345 581 70,104 2,76
36 13,8425 565 72,136 2,84
37 13,475 550 74,1172 2,918
38 13,1075 535 76,073 2,995
39 12,789 522 78,105 3,075
40 12,4705 509 80,0862 3,153
41 12,152 496 82,1182 3,233
42 11,8825 485 84,074 3,31
43 11,5885 473 86,106 3,39
17 29,3265 1.197 34,036 1,34
18 27,685 1.130 36,0426 1,419
19 26,2395 1.071 38,0492 1,498
20 24,941 1.018 40,0304 1,576
21 23,7405 969 42,0624 1,656
22 22,6625 925 44,0182 1,733
23 21,6825 885 46,0502 1,813
44 11,319 462 88,0872 3,468
45 11,074 452 90,1192 3,548
46 10,829 442 92,075 3,625
47 10,6085 433 94,0562 3,703
48 10,388 424 96,0628 3,782
49 10,1675 415 98,0948 3,862
50 9,9715 407 100,076 3,94
76
Operation
TABLE 1. WET HIDING POWER AND WET FILM THICKNESS
Cryptometer
Setting
Hiding Power Thickness
No. 3.5 Top Plate
K = 0.0035
Operation
24 11,858 484 84,074 3,31
25 11,417 466 87,503 3,445
26 10,976 448 91,059 3,585
(mm) ( M²/L) ( ft.²/gal.) (microns) (mils)
1 284,69 11.620 3,5052 0,138
2 142,345 5.810 7,0358 0,277
3 94,9375 3.875 10,4902 0,413
4 71,246 2.908 14,0208 0,552
5 56,987 2.326 17,5006 0,689
6 47,481 1.938 21,0058 0,827
7 40,719 1.662 24,511 0,965
8 35,623 1.454 28,0162 1,103
9 31,654 1.292 31,496 1,24
10 28,469 1.162 35,0266 1,379
11 25,921 1.058 38,5064 1,516
12 23,765 970 42,037 1,655
13 21,903 894 45,5168 1,792
14 20,335 830 49,022 1,93
15 19,012 776 52,5272 2,068
16 17,787 726 56,007 2,205
27 10,535 430 94,488 3,72
28 10,192 416 98,044 3,86
29 9,8 400 101,6 4
30 9,506 388 104,902 4,13
31 9,212 376 108,458 4,27
32 8,918 364 112,014 4,41
33 8,624 352 115,57 4,55
34 8,379 342 118,999 4,685
35 8,134 332 122,428 4,82
36 7,938 324 123,444 4,86
37 7,693 314 129,54 5,1
38 7,497 306 133,096 5,24
39 7,301 298 136,398 5,37
40 7,105 290 139,954 5,51
41 6,958 284 143,51 5,65
42 6,762 276 146,812 5,78
43 6,615 270 147,955 5,825
17 16,758 684 58,9788 2,322
18 15,827 646 62,992 2,48
19 14,994 612 66,548 2,62
20 14,259 582 70,0278 2,757
21 13,573 554 73,4568 2,892
22 12,936 528 76,9874 3,031
23 12,397 506 80,518 3,17
44 6,468 264 154,178 6,07
45 6,321 258 157,48 6,2
46 6,1985 253 161,036 6,34
47 6,0515 247 164,592 6,48
48 5,929 242 168,148 6,62
49 5,8065 237 171,704 6,76
50 5,684 232 175,006 6,89
98
Operation
TABLE 1. WET HIDING POWER AND WET FILM THICKNESS
Cryptometer
Setting
Hiding Power Thickness
No. 7 Top Plate
K = 0.007
Operation
24 5,929 242 168,148 6,62
25 5,7085 233 175,006 6,89
26 5,488 224 182,118 7,17
(mm) ( M²/L) ( ft.²/gal.) (microns) (mils)
1 142,345 5.810 7,0104 0,276
2 71,05 2.900 14,0208 0,552
3 47,4075 1.935 21,0058 0,827
4 35,5495 1.451 28,0162 1,103
5 28,4935 1.163 35,0266 1,379
6 23,7405 969 42,037 1,655
7 20,3595 831 49,022 1,93
8 17,8115 727 56,007 2,205
9 15,827 646 62,992 2,48
10 14,2345 581 70,0532 2,758
11 12,9605 529 76,835 3,025
12 11,8825 485 83,82 3,3
13 10,9515 447 90,932 3,58
14 10,1675 415 98,044 3,86
15 9,506 388 104,902 4,13
16 8,8935 363 111,887 4,405
27 5,2675 215 188,976 7,44
28 5,096 208 196,088 7,72
29 4,9 200 203,2 8
30 4,753 194 210,058 8,27
31 4,606 188 217,17 8,55
32 4,459 182 224,155 8,825
33 4,312 176 231,14 9,1
34 4,1895 171 236,855 9,325
35 4,067 166 245,11 9,65
36 3,969 162 252,095 9,925
37 3,8465 157 259,08 10,2
38 3,7485 153 266,192 10,48
39 3,6505 149 273,05 10,75
40 3,5525 145 280,162 11,03
41 3,479 142 287,274 11,31
42 3,381 138 294,132 11,58
43 3,3075 135 301,244 11,86
17 8,379 342 118,872 4,68
18 7,9135 323 125,984 4,96
19 7,497 306 133,096 5,24
20 7,1295 291 140,208 5,52
21 6,7865 277 146,939 5,785
22 6,468 264 153,924 6,06
23 6,1985 253 161,036 6,34
44 3,234 132 308,102 12,13
45 3,1605 129 315,214 12,41
46 3,087 126 322,072 12,68
47 3,0135 123 328,93 12,95
48 2,9645 121 336,042 13,23
49 2,891 118 342,9 13,5
50 2,842 116 350,012 13,78
1110
Operation
WHERE
The formulas used to construct the above Table 1
may be simplied as follows
H. P. = 40.7/K x L
and
T = K x L x 39.4
H. P = Wet Hiding Power
(in square feet per gallon)
K = Top Plate Wedge Constant (slope)
L = Cryptometer Setting (in millimeters)
T = Wet Film Thickness (in mils or
thousandths of an inch)
12
253 017 659 EDFIS 0408 Europe
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