ASTM C285-10(2020)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C285 − 10 (Reapproved 2020)
Standard Test Methods for
Sieve Analysis of Wet-Milled and Dry-Milled Porcelain
Enamel
This standard is issued under the fixed designation C285; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
These test methods provide a rapid means of determining the fineness of glass frit in wet- or
dry-milled porcelain enamel coating materials by sieve analysis. Fineness is a key predicator of
fusibility, tearing, gloss, opacity, suspension in the slip, and ease of spraying because of the direct
relationship to surface area.
1. Scope 2. Referenced Documents
1.1 These test methods cover the determination of the 2.1 ASTM Standards:
fineness of frit in wet- or dry-milled porcelain enamels and E11Specification forWovenWireTest Sieve Cloth andTest
other ceramic coatings for metals by means of the No. 200 Sieves
(75-µm) or No. 325 (45-µm) sieve.
3. Significance and Use
1.2 The two methods appear as follows:
3.1 The fineness of the frit has a direct bearing on many of
Sections
itsproperties,suchasfusibility,tearing,gloss,opacity,suspen-
Method A—Referee Method 4to9
sion in the slip, and ease of spraying.
Method B—Routine Method 10 to 14
METHOD A—REFEREE METHOD
1.3 MethodAis intended for use where a referee method of
higher accuracy is required, while Method B is intended to
4. Apparatus
meet the needs of normal enamel plant production control
operations where a rapid, simplified method of sieve testing is
4.1 Balance—The balance or scale shall be of at least 500-g
required. The accuracy of the simplified method has proved to
capacity, and accurate to 0.1 g.
be entirely adequate for this use. The simplified test, however,
4.2 Sieves—The sieves shall conform to Specification E11.
is not recommended where high accuracy is required.
They shall include the No. 40 (425-µm) sieve and also the No.
1.4 This standard does not purport to address all of the
200 (75-µm) or the No. 325 (45-µm) sieve, or both.ANo. 325
safety concerns, if any, associated with its use. It is the
sieve shall be used when the fineness is such that, from a
responsibility of the user of this standard to establish appro-
sample containing 100 g of dry solids, less than2gis retained
priate safety, health, and environmental practices and deter-
on a No. 200 sieve. An 8-in. (203-mm) full-height sieve is
mine the applicability of regulatory limitations prior to use.
recommended. This height is preferred because there is less
1.5 This international standard was developed in accor-
tendencytofloodorsplash,andalsobecauseitfitscommercial
dance with internationally recognized principles on standard-
automatic tapping and shaking machines. All sieves used for
ization established in the Decision on Principles for the
testing shall be standardized initially and after every 50 tests
Development of International Standards, Guides and Recom-
against a reference sieve tested by the National Bureau of
mendations issued by the World Trade Organization Technical
Standards and bearing its precision seal.The correction for the
Barriers to Trade (TBT) Committee.
sieveusedinthistestshallbedeterminedbysievingtestsmade
in conformity with the procedure of this test method. Identical
samplesshallbesievedthroughthereferencesieveandthetest
These test methods are under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatingsand are the direct responsibility of Subcommittee
B08.12 on Materials for Porcelain Enamel and Ceramic-Metal Systems. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2020. Published December 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ε1
approved in 1951. Last previous edition approved in 2015 as C285–10(2015) . Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/C0285-10R20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C285 − 10 (2020)
sieve. Test materials shall be chosen so that 5 to 10% of the continuous sieving. Weigh the portion of the sample retained
material will be retained on the reference sieve.The difference on the sieve to the nearest 0.1 g.
between the percentage residue on the reference sieve and that
6.3 Machine Sieving—If a mechanically operated sieve
on the test sieve is the amount of correction which shall be
shaker is used, vary the time during which the sieve (with pan
algebraically added to, or subtracted from, the correction for
and cover attached) and the sample are shaken, and note the
the reference sieve to obtain the final correction (Note 1). The
length of time necessary to operate the sieve shaker in order to
No. 40 sieve need not be calibrated.
get the same result as that obtained with hand sieving.
Calibrate the machine-sieving operation in terms of hand
NOTE 1—For example, when comparing the reference sieve with a test
sieving.
sieve, should 8.5 g be retained on the reference sieve and 7.5 g on the test
sieve, the total correction for the test sieve would then be 8.5−7.5,
or+1.0.
7. Procedure for Dry-Milled Enamel
4.3 Dryer—A suitable means for drying the sieves and slip
7.1 TransferthesamplequantitativelytotheNo.200or325
sample, without exceeding a temperature of 250°F (122°C),
sieve. Complete the sieving and weighing operation in accor-
shall be provided. No dryer is needed for sieve tests of
dance with 5.2 or 5.3. Make tests in duplicate.
dry-milled enamel.
8. Calculation and Report
4.4 Mechanically Operated Sieve Shaker—The mechanical
shakingdeviceshallbesuchastoproducealateralandvertical
8.1 Using the average of duplicate runs, report the fineness
motion of the sieve, accompanied by a jarring action so as to
of the frit in percentage by mass (to the nearest 0.1%) of the
keep the sample moving continuously over the surface of the
drysolidscontentofthesampleretainedontheNo.200or325
sieve. If a machine shaker is to be used, the thoroughness of
sieve. The weight in grams is equivalent to weight percentage.
sieving shall be tested by comparing and calibrating with the
hand method of sieving, as described in Section 6.
9. Precision and Bias
9.1 Precision—It is generally accepted within the porcelain
5. Sample
enamelindustrythatduplicatetestsrunbythesameoperatorin
5.1 Wet-Milled Enamel—Select a sample of slip representa- the same laboratory should show a precision of 60.5 or less.
tive of the material to be tested. Protect samples from evapo- Failure to duplicate determinations within this limit indicates
ration. Determine the water content of the slip by drying a the necessity for repet
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