![]() Nor is there a single cup that allows good measurement of all possible viscosities. It's an extrapolation way off the chart :-(Ī carpenter doesn't drive tacks with a sledgehammer, nor landscape spikes with his tack hammer he uses different hammers for different jobs. A Ford cup with efflux time "more than 200 seconds", is meaningless. That is,Ĭentipoise = centistokes x specific gravityīut as previously explained to Aniruddha, you're using the wrong cup. It includes a chart by Euverard showing a conversion factor of 3.7 for the Ford #4 cup. On Amazon] as it has an excellent chapter on the subject of viscosity and its measurement with the various cups and devices. Please also try to also get hold of the ASTM Gardner/Sward "Paint Testing Manual" [affil link ![]() covers viscosity measurement with the Ford Cup. Can you correlate these parameters to the disagreement of the cups? How do I say that a particular #4 cup is faulty and should be discarded?Ī. Can anyone explain to me the reasons? I can verify the volume of cup and the dia of orifice. I find that Two cups - #4 cups never give the same results. According to the previously referenced chart at it looks like the efflux time for an F5 cup would be about 48 seconds. The viscosity which you are trying to measure is beyond the workable range of an F4 cup. Using a cup with a large hole to measure the viscosity of thin liquids that will drain in a flash would be like timing a jackrabbit with a sun dial and using a cup with a tiny hole to measure the viscosity of very thick fluids would be like using a stop watch to time the lifespan of an tortoise :-) Meghan's posting was from 3 years ago so he might not be around to answer.īut I think the basic issue is that there are practical limits to such rough conversions.
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