Technical Library

Outline

Prefix:

  • DMS = Dimethylsiloxane

Suffix:

  • 1st character = Trimethylsiloxy-terminated
  • 2nd character = viscosity in decades, i.e. 10x
  • 3rd character = viscosity to 1 significant figure
CentistokesPoiseSSUZahn #1Zahn #2Zahn #3Zahn #4Zahn #5Ford #3Ford #4Krebs unitsSAELiquid example
10.010.31Water
100.160301695
200.210037181210
400.421052222518
600.6320682733253310
800.84308134413137
100153041121050344020olive oil
20021,00082281710905852
30031,4753424151307460
40041,9504630201701126430glycerine
50052,4805838252181436840
1,000104,60069493902648590castor oil
2,000209,400800540103
3,0003014,5001,230833121
4,0004018,5001,5701,060133molasses
5,0005023,5001,350corn syrup
6,0006028,0001,605
7,0007032,5001,870
8,0008037,0002,120
9,0009041,0002,360
10,00010046,5002,670honey
15,00015069,400
20,00020092,500
30,000300138,600
40,000400185,600
50,000500231,000
60,000600277,500
70,000700323,500
80,000800370,500
90,000900415,500
100,0001,000462,000sour cream
125,0001,250578,000molasses*
150,0001,500694,000
175,0001,750810,000
200,0002,000925,000peanut butter
viscosities at 25 °C unless otherwise stated
*measured at 2 °C (a cold winter day)
Note: The precision of conversion in this table is limited by two factors. It assumes that the density of liquids is 1 so that stokes and poises are the same and that viscosity is independent of shear rate, i.e., the fluid is Newtonian. To correct for density in converting from centistokes to centipoises, multiply specific gravity by centistokes.

Any standard viscosity grade of polydimethylsiloxane can be blended together with another viscosity grade of the same fluid to produce an intermediate viscosity. This chart provides a means for determining the proper blend ratio. The chart should be used as follows:

  • Decide upon the viscosity grades to be blended. For high accuracy, measure the actual viscosity of the blending fluids.
  • Locate the lower viscosity on the left hand scale. Locate the higher viscosity on the right hand scale.
  • Connect these two points with a straight line.
  • Locate the point where the line indicating the desired blend viscosity intersects the constructed line.
  • From this point, follow down to the horizontal scale to read the percent of the higher viscosity fluid to use in the blend.

This method is reasonably accurate in predicting blend viscosity when the two fluids differ in viscosity by no more than one magnitude (one power of ten). When fluids covering a wider range are blended, the chart will only approximate the finished viscosity. To achieve a viscosity of 800 cSt as shown in the example, 68% of 1000 cSt and 32% of 500 cSt fluids are blended.

calculation basis for blending