To: "Vladimir Galogaza" , atm{at}shore.net
From: tkrajci{at}san.osd.mil
Reply-To: tkrajci{at}san.osd.mil


I made the post about the viscosity tester at work, and my book was not
handy, so I did not try and describe it for fear of getting it wrong.

Looking at the book now:

Pointed steel rod weighted with 1Kg (2.2Lbs) is allowed to penetrate a
pitch sample for 5 minutes.  Depth of penetration is measured, and compared
to a chart/nomogram to see if the pitch is 'suitable.'  (The nomogram has
temperature on one axis and penetration distance on the other axis...then
you see if your results are within the preferred range of pitch viscosity.)

The steel rod's point is tapered at a 14 degree angle and the tip is
flattened to about 0.04 inch (about 1mm).

You can use just about any framework of wood or metal with holes in it to
support the steel rod upright while it's pressed down against the pitch by
the 1Kg mass.  You do not need a dial indicator to measure penetration
depth...any finely divided ruler will work.

The desired range of pentration depth after 5 minutes is between 0.02 and
0.25 inches, with 0.07 inches considered the ideal.

The nomogram shows a slightly complex relationship between temperature and
viscosity.  With the nomogram you can make one test at a given
temperature...and use the nomogram to find out at what temperature you
'should' be at for ideal results.  Without the nomogram you'll have to test
at various temperatures until you find your ideal temp.

I'll try and scan the nomogram and send it to interested users tomorrow.

Tom Krajci
Tashkent, Uzbekistan

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