ASTM_C_693_-_93_2013.pdf

Designation:C69393(Reapproved 2013)Standard Test Method forDensity of Glass by Buoyancy1This standard is issued under the fixed designation C693;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the densityof glasses at or near 25C,by buoyancy.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:E12 Terminology Relating to Density and Specific Gravityof Solids,Liquids,and Gases(Withdrawn 1996)23.Terminology3.1 Definitions:3.1.1 density of solidsthe mass of a unit volume of amaterial at a specified temperature.The units shall be stated asgrams per cubic centimetre(see Terminology E12).4.Significance and Use4.1 Density as a fundamental property of glass has basicsignificance.It is useful in the physical description of the glassand as essential data for research,development,engineering,and production.5.Apparatus5.1 Analytical Balance,with sensitivity and accuracy of 0.1mg.5.2 Beaker,of convenient capacity(250 to 750 cm3)to fitinside the balance chamber and allow immersion of the basketor wire loop specimen holder in distilled water.5.3 Thermometers,calibrated(20 to 30C),sensitive to0.1C for determining air and water temperatures.5.4 Nickel-Chromium-Iron or Platinum-Alloy Wire,lessthan 0.2-mm diameter for suspending the specimen either in abasket or a loop made of the same wire.The suspension wireshall be cleaned by degreasing or heating in a vacuum.3Anacceptable alternative method of cleaning the platinum-alloywire is to heat in an oxidizing gas flame until there is no longerany color emitted from the gases passing around the wire.5.5 Weights,with accuracy of 0.1 mg.5.6 Barometer,with sensitivity of 1-mm Hg(optional,seeNote 3).6.Reagent6.1 Distilled Water,fresh,boiled,and used within 24 h,allowed to stabilize at balance air temperature for at least 2 hin the beaker.7.Test Specimen7.1 Specimens weighing about 20 g,with a minimum ofseeds or other inclusions(Note 1),shall be taken or cut fromthe sample object,preferably in cylindrical or rectangular barform with smooth,slightly rounded surfaces having no cracksor sharp edges.NOTE1For a specimen of 20 g with a density of approximately 2.5g/cm3,a gaseous void of diameter 2 mm will cause an error in measureddensity of 0.05%.7.2 The specimens shall be cleaned,handling them withtweezers throughout subsequent operations,by immersionpreferably in an ultrasonic bath of hot nitric acid,chromic-sulfuric acid,or organic degreasing solvent,followed by arinsing in alcohol and distilled water.For samples only soiledby ordinary handling or exposure,adequate cleaning may beobtained using a warm 2%volume MICRO-brand4detergent,followed by a deionized or distilled water rinse.8.Procedure8.1 Hold the specimens and covered beaker of boileddistilled water near the laboratory balance until the water hascooled to ambient temperature before weighing.1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee C14.04 onPhysical and Mechanical Properties.Current edition approved Oct.1,2013.Published October 2013.Originallyapproved in 1971.Last previous edition approved in 2008 as C693 93(2008).DOI:10.1520/C0693-93R13.2The last approved version of this historical standard is referenced onwww.astm.org.3Bowman,H.A.,and Schoonover,R.M.,“Procedure for High Precision DensityDeterminations by Hydrostatic Weighing.”Journal of Research,National Bureau ofStandards,Vol 71C,No.3,JulyAugust 1967,pp.179198.4Manufactured by International Products Corporation,PO Box 70,Burlington,NJ 08016.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.2 Read the laboratory air temperature to the nearest 1C.Read the barometric pressure to the nearest 1-mm Hg.A fixedlaboratory average barometric pressure estimate is an accept-able alternative to the barometric pressure measurement(seeNote 3).Determine the density,A,of the air from Table 1.8.3 Weigh the glass specimen in air to the nearest 0.1 mgand record as WA.8.4 Place the beaker of water with immersed thermometeron a platform supporting it over the balance pan so that the panor balance arm is free to swing.8.5 Place the specimen in the basket or loop holder and hangthis holder from the balance arm by means of a suitable hookand the suspension wire.Immerse the basket and specimen byraising the beaker of distilled water until the surface of thewater is at a predetermined