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Home  >>  Products  >>  Viscosity  >>  S90 Zahn Viscosity Cups

S90 ZAHN Signature Series Dip Cup

All Stainless Steel Calibrated Viscosity Cup

S90 Dip Cup

  • S90 Zahn Signature Dip Viscosity cups are an improved version of the time honored Zahn Signature viscosity cups. GARDCO is the only producer authorized to use the Zahn name and has added the S90 designation to identify the improved viscosity cups manufactured on new state-of-the-art equipment to insure optimum quality and uniformity.

  • Calibration of the S90 Zahn cups match the earlier Zahn Signature cups.

  • Conversion formulas and tables relating cup efflux time in seconds to viscosity in centistokes are identical for both series of cups.

  • S90 Zahn cups qualify for certification under ANSI/NCSL Z540 or ISO/IEC 17025, ISO 9001, as applicable.

  • S90 Zahn cups are calibrated with standard "G" series oils traceable to the National Institute of Standards & Technology.

  • "G" series calibration oils are produced in accordance with ISO 9002.

  • NOTE: Efflux time from these cups does not meet ASTM specifications. Tables are available for converting S90 Zahn cup efflux time to EZ™ Zahn cup efflux time which complies with ASTM D4212.





  • Cup flow characteristics are defined by a mathematical formula and standard “G” series oils.
  • Furnished with each S90 Zahn cup is a conversion table relating cup efflux time to the nearest tenth of a second to viscosity in centistokes.
  • S90 Zahn cups, with the above advantages, cannot be confused with other, lesser defined cups as they are produced, calibrated and sold only by Paul N. Gardner Company and authorized dealers.
  • Ransom & Randolph recommends the S90 Zahn cups as the most reliable viscosity cups to measure and control the consistency of ceramic shell slurries.



Technical Data

Range Specification
Item Number
Cup No. Seconds Range Centistoke Range
VI-2101 1 31 to 60 15 to 78
VI-2102 2 19 to 60 39 to 238
VI-2103 3 11 to 60 63 to 604
VI-2104 4 10 to 60 97 to 899
VI-2105 5 10 to 60 219 to 1627
Certificate of Calibration available at additional charge for all cups.

Conversion Formulas
Cup No. Efflux Time Seconds “T” from Centistokes “V” Centistokes “V” from Efflux Time in seconds “T”
T = (V + V2 + 6805) ÷ 3.18
V = 1.59T - 1070 ÷ T
T = (V + V2 +12707) ÷ 8.36
V = 4.18T - 760 ÷ T
T = (V + V2 + 23529) ÷ 20.46
V = 10.23T - 575 ÷ T
T = (V + V2 + 32983) ÷ 30.26
V = 15.13T - 545 ÷ T
T = (V + V2 + 58903) ÷ 54.54
V = 27.27T - 540 ÷ T
Note: Furnished with each cup is a conversion table for each tenth of a second within the cup range.

Standard“G” Series Calibrating Oils
Catalog Number Oil Number Use With Cup Number Nominal Centistokes* at 25°C., 77°F.
VI-3805 G-20 1 35
VI-3815 G-60 2 120
VI-3820 G-100 3 230
VI-3825 G-350 4 and 5 880
*Certified value is printed on container label. Note: A graph is furnished with each cup showing efflux time of the "G" oil from 20 to 27 degrees Celsius.

These standard oils prepared expressly by the Cannon Instrument Company for the Paul N. Gardner Company are produced in accordance with ISO/IEC 17025:2005, ISO/IEC Guide 34:2009, ISO 9001:2008.

Caution: Silicone fluids should not be used to calibrate viscosity cups. These materials change the interface between the cup surface and the test material and therefore change the cup calibration. The following is taken from ASTM D445: Viscometers used for silicone fluids should be reserved for the exclusive use of such fluids. Solvent washings from these viscometers should not be used for cleaning other viscometers.


Conversion Table Between Efflux Time in Secs. and Centistokes

Conversion Table

Flow characteristics of S90 Zahn cups are accurately defined by mathematical formula relating cup efflux time to viscosity. The formula for each cup in the series is shown in the Conversion Formula table. For convenience, the formula for each cup has been solved for each tenth of a second within the normal cup range. Results are available in table form as shown greatly reduced at the left and are furnished with each cup. They are also available in sets for each cup in the series.

Use the table as follows: Assume an efflux time of 45.6 seconds. Read down the left column to the 45 line and then to the right on this line to the 0.6 column. The value at the intersection is 173.9 centistokes. The table may be read in reverse to find efflux time in seconds from a known centistoke value.


Instructions For Use

  1. Select the cup to be used from the Range Specification table.
  2. Insure that the cup is clean, especially around the orifice.
  3. Adjust temperature of the material to be tested, if necessary.
  4. Holding the cup by the ring, immerse it into the test material.
  5. Measure and record temperature of material encompassed by cup.
  6. Hold cup vertically by inserting index finger into handle ring. In a quick, steady motion, lift the cup out of the sample material, starting the timer when the top edge of the cup breaks the surface. During the flow time, hold the cup no more than 6” above the level of the sample material.
  7. Stop the timer when the first definite break in the stream at the base of the cup is observed.
  8. Record cup name, number and efflux time in seconds with temperature.
  9. Promptly clean the cup taking care not to abrade orifice. Use a length of nylon fishing line to clean the orifice.


Care of Cup

GARDCO produced and calibrated S90 Zahn viscosity cups are made of stainless steel except for the name plate. These cups will give years of satisfactory service requiring only thorough cleaning following each use. Even so, it is good practice to periodically confirm cup calibration. This is easily done with use of appropriate “G” oil listed in the Calibrating Oils table. Centistoke label value of the oil is traceable to the National Institute of Standards and Technology.


Cleaning Viscosity Cups After Use


Guide for removing the G-series calibrating oil from Gardco viscosity cups.

Any remaining material in the cup must be removed by flushing with a suitable solvent. Light naphtha, heptane, octane, highly aromatic solvents, and or any other petroleum-derived hydrocarbon solvent can be used. Varsol® is a commercial solvent that works very well for this purpose.

Completely dry the viscosity cup with a lint free cloth. Use a highly volatile solvent for a second cleaning as since any remaining hydrocarbon solvents from the first process will evaporate quickly after the sample has been flushed from the cup. Hypersolve, MEK and Alcohol can be used in aluminum cups and Hypersolve and Alcohol for the stainless steel cups. Acetone is commonly used as the second solvent because of its high volatility and its ability to dissolve traces of petroleum solvents and water.

In the third process a low velocity stream of clean air will be sufficient to evaporate remaining traces of any volatile solvent. Be aware, avoid rapid evaporation of these solvents as this can cool the surface to such an extent that humid air may be brought below the dew point, causing a film of water to form on the cup.

Varsol is a registered trademark of the Exxon Company


Notice To All S90 Zahn Viscosity Cup Users

S90 Zahn Signature Series Dip cups do not meet ASTM Specification D4212. Not all S90 Zahn Cups deviate from the standard by the same amount - the range being from near compliance to a variance exceeding a factor of two.

Manufacturing procedures include calibration with oils traceable to the National Institute of Standards and Technology. Certification with compliance to ANSI/NCSL Z540 or ISO/IEC 17025, ISO 9001, as applicable, is available. Tables are available which convert between S90 Zahn Signature and EZ™ cups of the same number, to the nearest tenth of a second, to assist those who need to work with both established standards.





Atkins Platinum RTD Thermometer and Probe System RTD Thermometer
This highly accurate digital thermometer utilizes platinum RTD probe sensor technology. The probe is permanently attached to provide a splash-proof instrument with improved total system accuracy.
Technical Data
Resolution: 0.1 degrees
Range: -76°F to 500°F (-60°C to 260°C)
Accuracy: ±0.5F° from -76.0°F to 199.9°F; ±1F° from 200°F to 500°F
(±0.3C° from -60.0°C to 93.3°C; ±1C° from 200°C to 260°C)
Battery Life: 1800 hours, Two AAA Batteries Included


Price - S90 Manual

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
Trade-in any brand Zahn Cup to receive 20% off (discount on price of cup only, not certification, cannot be combined with anothert offer)
Learn more about our FREE viscosity calculater. CLICK HERE.
VI-2101 No. 1 S90 Zahn Viscosity Cup (Each) with Conversion Chart $140.00
VI-2101/C Certified No. 1 S90 Zahn Viscosity Cup (Each) with Conversion Chart 313.00
VI-2102 No. 2 S90 Zahn Viscosity Cup (Each) with Conversion Chart 140.00
VI-2102/C Certified No. 2 S90 Zahn Viscosity Cup (Each) with Conversion Chart 313.00
VI-2103 No. 3 S90 Zahn Viscosity Cup (Each) with Conversion Chart 140.00
VI-2103/C Certified No. 3 S90 Zahn Viscosity Cup (Each) with Conversion Chart 313.00
VI-2104 No. 4 S90 Zahn Viscosity Cup (Each) with Conversion Chart 140.00
VI-2104/C Certified No. 4 S90 Zahn Viscosity Cup (Each) with Conversion Chart 313.00
VI-2105 No. 5 S90 Zahn Viscosity Cup (Each) with Conversion Chart 140.00
VI-2105/C Certified No. 5 S90 Zahn Viscosity Cup (Each) with Conversion Chart 313.00
VI-2100/C NIST & ANSI/NCSL Z540 or ISO/IEC 17025, ISO 9001, as applicable, Calibration Certificate 173.00
VI-3805 G-20 Certified Viscosity Standard - Pint 98.00
VI-3815 G-60 Certified Viscosity Standard - Pint 98.00
VI-3820 G-100 Certified Viscosity Standard - Pint 98.00
VI-3825 G-350 Certified Viscosity Standard -Pint 98.00
VI-VCC Viscosity Cup Equivalent Wall Chart (download here) FREE
Equivalent Charts cover Gardco Calibrated Viscosity Cups and are based on conversion formulas of a type & with parameters as referenced in The Encyclopedia of Polymer Science & Engineering (Vol. 4, Second Edition, John Wiley & Sons, Inc.). Standard oils traceable to the National Institute of Standards & Technology were used in experimental development of these formulas.
VI-201901 Aluminum Carousel Stand w/5 Hooks 330.00
TM-AX705 Ultimate Stopwatch, 1/100 34.00
TM-AX705/C Ultimate Stopwatch, 1/100 - Certified traceable to N.I.S.T 57.00
TH-0482 Thermometer, Glass, blue spirit filled, 4-1/2", 20° to 30°C 55.00
TH-16100860 GT-100R Thermometer, Stainless, 8" Stem, 25° to 125°F 37.00
TH-16100875 GT-100R Thermometer, Stainless, 8" Stem, 0° to 50°C 37.00
TH-36036-FC Platinum RTD Thermometer System (-76° to 500°F and -60° to 260°C) 508.00
SS-80600 Griffin Beaker SS, 600 ml 51.00
Viscosity Cups are non-returnable items. Subject to final sale.
S90TM is a Registered Trade Mark of the Paul N. Gardner Company, Inc


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