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Gardner Standard Bubble Viscometers

Meets ASTM D1545, D1545, D1725; AOC:Ka 6-63; Federal Test Method Standard 141a:4272; Federal Test Method Standard 141D:4261.1

Gardner Standard Bubble Viscometers

Sets of Filled Standard Tubes From A-5 to Z-10 series

Set of 20 bubble tube standards designated A thru T with 2 empty tubes (Grade A, Class G) and directions for use, complete in storage case. Weight: 3 lbs net; 7 lbs shipping weight.

  • Economically priced
  • Long lasting shelf life up to 15 years
  • Ideal to measure the kinematic viscosity of resins and varnishes
  • Easy to compare and rank the sample with the bubble viscometer standards



Cargille Empty Viscosity Tubes For Measuring Viscosity By The Air Bubble Rise Method Meets ASTM D 1545 - Rheology is a branch of science dealing with the deformation and flow of materials which includes the subject of viscosity. Viscosity is a measurement of internal friction, or resistance, to flow by external forces. Viscosity is the ratio of shear force to shear rate (the slope of the curves in Fig. 1) expressed by:


The viscosity of many materials depends on shear rate and is classified accordingly, Fig 2. Viscosity is expressed as Absolute, n, and Kinematic, v. Absolute viscosity is determined by measuring the shear force required to produce a given shear rate and is independent of the density of the liquid.

Kinematic viscosity is measured by the time required for a given volume of liquid to flow through a capillary or restriction. It is related to flow caused by the hydrostatic head of the liquid and therefore strongly dependent on density.

The relationship between Absolute and Kinematic viscosity is given by the following, where p is density:
 v = n/p
One of the simplest methods for determining Kinematic viscosity is by the rising bubble technique employing matched viscosity tubes. The method is visual, convenient, rapid and easily learned by technical and non-technical personnel.
Figure 1 and 2
Fig. 1 Fig. 2

Technical Data

Technical Data
Class Score marks I.D. ±0.025mm Method Of Testing
Time-Test, 10.65mm (ASTM D 1545) 108mm, 100mm, 27mm 10.65
(equivalent to Gardner
N Grade Tubes)
Bubble time rise or bubble comparisons
Class “G-10.65” 108mm, 100mm 10.65
(equivalent to Gardner
A Grade Tubes)
Bubble comparisons to Gardner Standards; or to calibrated standards with identical tube dimensions
Class “V-10.75” 108mm, 100mm 10.75
(equivalent to Gardner
B Grade Tubes)
NOTE: All score marks are measured from the center of the outside bottom.
Technical Data
Viscosity Tubes are manufactured to the closest possible tolerances and then precisely measured for final selection.

Note: Inside diameter tolerance closer than ±0.025mm is unnecessary since variations in viscosity readings or comparisons would be imperceptible.
Length: 114mm ±2mm
Wall Thickness: .0.65mm
Tolerance, I.D.: ±0.025mm
Composition: Soda-lime glass, flat bottom
Score Height Tolerance: ±0.5mm

Bubble Methods

Rising Bubble Technique, Principle - The time required for an air bubble in a liquid to rise is directly proportional to its viscosity. Bubble rise rates vary with the inside diameters of viscosity tubes; therefore, the tubes must be precision matched to a tolerance that will keep bubble rise rate variations below the level of visual detection. Variations in viscosity readings or comparisons are visually imperceptible from viscosity tubes with inside diameter tolerances closer than ±0.025mm. Any variations in readings are attributed to differences in viscosities. Viscosity is determined by either measuring the time an air bubble takes to pass between two specifically spaced marks on viscosity tubes, or by comparison to the bubble rate rise of calibrated viscosity standards. The accuracy of the method is therefore a function of precision matching of tube bores and identical score heights, which are measured from the center outside bottom. Other factors, such as uniformity of temperature and verticality of tubes, influence timed bubble travel and controlled laboratory techniques are essential for precise results. For example, a variation in temperature of 0.1°C will cause a 1% variation in the timed bubble travel, and a one radius departure from tube verticality may introduce a 10% error in the timed bubble travel.

Procedure For Using Viscosity Tubes - A viscosity tube is filled to the 100mm level score with the material to be tested. A cork is inserted to the 108mm score which provides and fixes a uniform air bubble. The sample, and standard if used, is placed in a suitable rack and immersed in a water bath until a uniform temperature of 25°C (77°F) is attained. If viscosity determinations are performed by referral to comparison samples of known viscosities or precisely calibrated standards, then they, too, should be at the same temperature as the samples. Viscosity is determined by one of two methods:

Comparison Method - The bubble rate rise of the samples is compared to samples of known viscosities or calibrated standards contained in tubes of the same dimensions. The rack containing the samples and standards is removed from the water bath, held vertically to stabilize the air bubbles and quickly inverted maintaining verticality. A comparison of air bubble speed of the samples to the standards permits estimation of viscosity; the faster the rate of bubble rise, the lower the viscosity. The user may prepare viscosity standards or employ Gardner Viscosity Standards.

Time-Method (ASTM D 1545) - TimeTest Tubes are required to determine viscosity by the Timed-Method. The length of time, in seconds, required for an air bubble to pass from the 27mm to 100mm score mark, a distance of 73mm, is approximately equal to the viscosity of the liquid in “Stoke” units; alternatively, viscosity may be expressed in “Bubble Seconds.” It is important to note that the position of the air bubble in relation to the 27mm score should be similar at the end of the test on the 100mm score.

Viscosity Tube Selection Guide - Viscosity Tubes are divided into three Classes as determined by precision sorting in accordance with bore size, number of score marks and contemplated method of use for bubble rise testing, Fig. 2. The numbers assigned refer to the bore size, which is expressed in mm.

Time-Test Viscosity Tubes, 10.65mm - Time-Test Viscosity Tubes are frequently referred to as ASTM D-1545 Tubes, which originated from the adopted standard method of test for viscosity as described in ASTM D-1545 issued by the American Society for Testing and Materials. Time-Test Tubes are scored in three places: Fig. 3: 27mm, 100mm and 108mm. The score mark at 27mm is used for a 73mm timed travel. Time-Test Viscosity Tubes are also subjected to additional testing procedures to ascertain the 10.65mm bore which is very critical for precision measuring.

Class “G-10.65” and “V-10.75” Tubes - Class “G-10.65” and “V-10.75” Viscosity Tubes are used principally for direct comparisons to Gardner Viscosity Standards. Both Classes of tubes are inscribed at the 100mm and 108mm lengths, Fig. 4. For bubble rate rise comparisons to Gardner Viscosity Standards, the following equivalency chart is provided.

Score Marks - All Viscosity Tubes are permanently inscribed with two score marks, at 100mm and 108mm heights (Fig. 3) with the exception of Time-Test Viscosity Tubes, which have an additional score at 27mm (Fig. 4). In compliance with ASTM D 1545, all score marks are measured from the center outside bottom of the tubes. The score mark at 100mm represents the filling level and the 108mm score is used to fix the size of the air bubble in the tube by inserting a cork to this mark. The 27mm and 100mm scores on Time-Test Viscosity Tubes are used to time the bubble rise.

Specification References: American Oil Chemists Society (AOCS), Method Ka6-63, American Society For Testing and Materials D1131 53 (1975), D1545 89 D1725 62 (1970), Federal Test Method Standard (FTMS) Method 4271

Fig. 3 Bubble Tube Diagram
Fig. 3

Fig. 4 Bubble Tube Diagram
Fig. 4


Empty Viscosity Tubes
  • Knowing the approximate viscosity, pick four standard tubes closest in viscosity to your sample
  • Fill the sample tube with liquid, insert a cork, and then using the tube holder insert the four lettered tubes and the sample tube into the holder
  • Turn over the holder and visually compare what letter best matches the rise time of the bubble in the sample
  • The rise time in seconds of the sealed tubes and samples can also be determined using a basic timer
  • Please be aware of the following accuracies when performing the test: Temperature control: 1°C = 10% error - Verticality control: 5° slant = 10% error - Tube I.D. control: 0.1mm = 2% error
Gardner Empty Viscosity Tubes


Hand-held Holder for 5 Tubes

Hand-Held Tube Holder
Hand-Held Sturdy metal frame with plastic handle holding 5 tubes in one row by means of spring clips. Flat ends allow holder to be set in vertical position in water bath or on table.

Comes without tubes. Weights: 1/2 lbs net; 2 lbs shipping weight.



Tube Caps

Tube Caps
These black cap plugs add an additional level of protection to the top of the bubble tubes, it protects the wax from breaking off and it also protects the sealed glass from breakage when accidentally dropped.

Pictured right is a bubble tube shown with and without protective cap.



High quality, short length corks, properly fit viscosity tubes so that the small end is in firm contact with inside of tubes.

Prevents small extraneous bubbles from interfering with timed bubble movement.


Viscosity Tube Holder Box Viscosity Tube Holder Box

A durable, compact, solid, fiberboard Sample Storage Box with attractive dark green, moisture and abrasive resistant exterior covering holds up to 100 viscosity tubes in partitioned compartments. The compartments are arranged 5X20 and are alpha-numerically indexed for rapidly locating stored viscosity samples.

Boxes are supplied with separate, correspondingly-numbered index charts for recording pertinent sample information, and an exterior card in a polished brass card holder for easily identifying the general contents of the sample storage box.


Rough Sort Tubes

Tubes unsuitable for viscosity applications are separated. Although these tubes are not precision matched or scored, they are adequate in bore size for diversified use in general industrial and laboratory procedures. These low coat rough sort tubes have an approxinnate bore size range from 10.20-10.75mm and offer a great value for general purpose use.


Shell Vials

Tubes exhibiting bore sizes exceeding Viscosity, Color and Rough Sort Tube specifications are available for innumerable laboratory applications where inside dimensional tolerance is critical. Dimensions 114mm long, approximate 12mm O.D., 0.65mm wall thickness.


Color Tubes

Critical color or turbidity comparisons are frequently affected by variations in the light path of the liquid sample. To minimize this “visual diluting” effect, tubes are available with matched bore sizes to ±0.05mm to insure replicate volume comparisons under similar light path conditions. Dimensions 114mm long , 10.80mm I.D., 0.65mm wall thickness.



Prices subject to change    Prices listed in US dollars for domestic shipments within US, Canada, & Mexico only    Export orders require quotations - click here for a quote     For more info call us 1-800-762-2478 or 954-946-9454.
Item Number Item Prices
180500501 N.I.S.T. Certification (only) for Individual Gardner Standard Bubble Tubes (price of tube not included) $275.00
Single Filled Standard Bubble Viscometer Tubes A through T
VI-VG-9100 Gardner Bubble Viscometer Set A thru T $1,650.00
VI-VG-9100/C Set with N.I.S.T. Certification 3,550.00
VI-VG-9101 Tube A - 53.6 Kinematic Centistokes 89.00
VI-VG-9102 Tube B - 68.8 Kinematic Centistokes 89.00
VI-VG-9103 Tube C - 92.7 Kinematic Centistokes 89.00
VI-VG-9104 Tube D - 102.9 Kinematic Centistokes 89.00
VI-VG-9105 Tube E - 122.7 Kinematic Centistokes 89.00
VI-VG-9106 Tube F - 151.9 Kinematic Centistokes 89.00
VI-VG-9107 Tube G - 160.0 Kinematic Centistokes 89.00
VI-VG-9108 Tube H - 210.8 Kinematic Centistokes 89.00
VI-VG-9109 Tube I - 224.2 Kinematic Centistokes 89.00
VI-VG-9110 Tube J - 268.2 Kinematic Centistokes 89.00
VI-VG-9111 Tube K - 287.9 Kinematic Centistokes 89.00
VI-VG-9112 Tube L - 302.3 Kinematic Centistokes 89.00
VI-VG-9113 Tube M - 335.4 Kinematic Centistokes 89.00
VI-VG-9114 Tube N - 345.2 Kinematic Centistokes 89.00
VI-VG-9115 Tube O - 377.9 Kinematic Centistokes 89.00
VI-VG-9116 Tube P - 408.8 Kinematic Centistokes 89.00
VI-VG-9117 Tube Q - 441.8 Kinematic Centistokes 89.00
VI-VG-9118 Tube R - 467.4 Kinematic Centistokes 89.00
VI-VG-9119 Tube S - 517.7 Kinematic Centistokes 89.00
VI-VG-9120 Tube T - 547.2 Kinematic Centistokes 89.00
Gardner Bubble Viscometers A5 thru A1
VI-VG-9000 Gardner Bubble Viscometers Set A5 thru A1 - Set of 5 bubble tube standards designated A5 thru A1, with 2 empty tubes (Grade A, Class G) and directions for use, complete in storage case. Weight: 1 1/2 lbs net; 5 lbs shipping weight. $525.00
VI-VG-9000/C Set with N.I.S.T. Certification 1,599.00
VI-VG-9001 Tube A5 - 5.1 Kinematic Centistokes 89.00
VI-VG-9002 Tube A4 - 7.1 Kinematic Centistokes 89.00
VI-VG-9003 Tube A3 - 14.0 Kinematic Centistokes 89.00
VI-VG-9004 Tube A2 - 21.3 Kinematic Centistokes 89.00
VI-VG-9005 Tube A1 - 31.0 Kinematic Centistokes 89.00
Gardner Bubble Viscometer Set, U thru Z6
VI-VG-9200 Gardner Bubble Viscometer Set, U thru Z6 - Set of 12 bubble tube standards designated U thru Z6, with 2 empty tubes (Grade A, Class G) and directions for use. Complete in case. Weight: 2 1/2 lbs net; 7 lbs shipping weight. $999.00
VI-VG-9200/C Set with N.I.S.T. Certification 2,920.00
VI-VG-9201 Tube U - 665.9 Kinematic Centistokes 89.00
VI-VG-9202 Tube V - 889.2 Kinematic Centistokes 89.00
VI-VG-9203 Tube W - 1073.0 Kinematic Centistokes 89.00
VI-VG-9204 Tube X - 1200.0 Kinematic Centistokes 89.00
VI-VG-9205 Tube Y - 1737.0 Kinematic Centistokes 89.00
VI-VG-9206 Tube Z - 2289.0 Kinematic Centistokes 89.00
VI-VG-9207 Tube Z1 - 2909.0 Kinematic Centistokes 101.00
VI-VG-9208 Tube Z2 - 4056.0 Kinematic Centistokes 101.00
VI-VG-9209 Tube Z3 - 4840.0 Kinematic Centistokes 101.00
VI-VG-9210 Tube Z4 - 7241.0 Kinematic Centistokes 101.00
VI-VG-9211 Tube Z5 - 9917.0 Kinematic Centistokes 101.00
VI-VG-9212 Tube Z6 - 15080.0 Kinematic Centistokes 101.00
Gardner Bubble Viscometer Set, Z7 thru Z10
VI-VG-9250 Gardner Bubble Viscometer Set, Z7 thru Z10 - Set of 4 bubble tube standards designated Z7 thru Z10 with 2 empty tubes (Grade A, Class G) and directions for use, complete in storage case. Weight: 1 1/2 lbs net; 5 lbs shipping weight. $575.00
VI-VG-9250/C Set with N.I.S.T. Certification 2,165.00
VI-VG-9251 Tube Z7 - 40650.0 Kinematic Centistokes 127.00
VI-VG-9252 Tube Z8 - 73280.0 Kinematic Centistokes 127.00
VI-VG-9253 Tube Z9 - 91500.0 Kinematic Centistokes 127.00
VI-VG-9254 Tube Z10 - 119000.0 Kinematic Centistokes 127.00
Empty Tubes
VI-730391 Empty Tubes, Grade A, Class G, 144/pkg w/corks, 10.65mm $330.00
VI-730392 Empty Tubes, Grade B, Class V, 144/pkg w/corks, 10.75mm 280.00
VI-730551 Empty Tubes, Grade N, 144/pkg w/corks & Time Test ASTM D 1545 360.00
0578 Protective Tube Cap for Bubble tubes, 20 pk 20.00
VI-VG-7420 Tube Holder 225.00
VI-44200/GR Rough Sort Tubes, bore size range 10.50-10.75 mm, 144/pkg 184.00
VI-44350/GR Viscosity/Color Tubes 10.80mm I.D., 0.65mm wall thickness, 144/pkg w/corks 237.00
VI-36132 Viscosity Tube Sample Storage box (Model CK-3) - (Ea.) 63.00
VI-44004 Corks (for Viscosity Tubes), 150 corks per package - (Pkg) 30.00


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