ASTM C631-95a(2004)

Standard Specification for Bonding Compounds for Interior Gypsum Plastering

ABSTRACT
This specification covers the minimum requirements for bonding compounds used in adhering interior gypsum plasters to structurally sound surfaces. The bonding compound should be a tinted film-forming material suitable for application by brush, roller, and spray. It shall have a non-oxidizing, non-toxic, and non-flammable composition, and have a smooth, homogeneous, and flexible consistency with no settling of the solids. It shall also be free of foreign matter, and shall not be noticeably affected by mild acid or alkali. The apparatus needed for the preparation of the compound are moist cabinet, forced drift type oven, freezer, balance, timing device, tamper, steel straight edge, metal-bladed spatula, paint brush, briquet testing machine, briquet molds, divider, and clips. Specimens shall be sampled, tested, and conform accordingly to the following performance requirements: bonding capability; degradation; high temperature stability; freeze-thaw stability, and bond strength.
SCOPE
1.1 This specification covers minimum requirements for bonding compounds for adhering interior gypsum plaster to structurally sound surfaces.  
1.2 This specification also covers test methods for determining performance requirements and physical properties.  
1.3 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units are approximate.  
1.4 The following safety hazards caveat pertains only to the test methods described in this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Oct-1995
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C11 - Gypsum and Related Building Materials and Systems
• Drafting Committee: C11.02 - Specifications and Test Methods for Accessories and Related Products

Relations

• Replaces: ASTM C631-95a(2000) - Standard Specification for Bonding Compounds for Interior Gypsum Plastering
• Effective Date: 10-Oct-1995
• Replaced By: ASTM C631-09 - Standard Specification for Bonding Compounds for Interior Gypsum Plastering
• Effective Date: 01-May-2009
• Referred By: ASTM C842-05(2021) - Standard Specification for Application of Interior Gypsum Plaster
• Effective Date: 10-Oct-1995
• Referred By: ASTM C843-23 - Standard Specification for Application of Gypsum Veneer Plaster
• Effective Date: 10-Oct-1995
• Referred By: ASTM C926-23 - Standard Specification for Application of Portland Cement-Based Plaster
• Effective Date: 10-Oct-1995

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C 631 – 95a (Reapproved 2004)
Standard Specification for
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Bonding Compounds for Interior Gypsum Plastering
This standard is issued under the fixed designation C631; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope suitable for application by brush, roller, and spray. The
compound shall be tinted to show, by visual inspection, where
1.1 This specification covers minimum requirements for
ithasbeenapplied.Thetintingmaterialshallnotshowthrough
bonding compounds for adhering interior gypsum plaster to
the material being bonded. The surfaces to which bonding
structurally sound surfaces.
compounds are applied shall be relatively smooth, clean, and
1.2 Thisspecificationalsocoverstestmethodsfordetermin-
dry. Surface coatings shall be removed if their nature indicates
ing performance requirements and physical properties.
an unsatisfactory condition. Surfaces shall be prepared in
1.3 The values stated in inch-pound units are to be regarded
accordance with the manufacturer’s directions.
as the standard. The SI equivalents of inch-pound units are
4.2 Consistency—The bonding compound shall be of a
approximate.
homogeneous nature with no settling of the solids. The
1.4 The following safety hazards caveat pertains only to the
compound shall be free of foreign matter, and when applied in
testmethodsdescribedinthisspecification: This standard does
accordance with the manufacturer’s directions, shall cover
not purport to address all of the safety concerns, if any,
evenly.
associated with its use. It is the responsibility of the user of this
4.3 Film Characteristics—A dry film of the bonding com-
standard to establish appropriate safety and health practices
pound shall be uniform and smooth and shall remain flexible.
and determine the applicability of regulatory limitations prior
Thefilmshallnotbenoticeablyaffectedbymildacidoralkali.
to use.
5. Performance Requirements
2. Referenced Documents
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5.1 Bonding Capability—A dry film of bonding compound
2.1 ASTM Standards:
shall be capable of bonding gypsum plaster immediately after
C11 Terminology Relating to Gypsum and Related Build-
drying and 10 days after drying when tested as specified in
ing Materials and Systems
Section 12.
C28 Specification for Gypsum Plasters
5.2 Degradation—Bonding compound that separates shall
C472 Test Methods for Physical Testing of Gypsum, Gyp-
beabletobere-mixedtoauniformconsistencywhentestedas
sum Plasters, and Gypsum Concrete
specified in Section 10.
C511 Specification for Mixing Rooms, Moist Cabinets,
5.3 High Temperature Stability—Thebondstrengthshallbe
Moist Rooms, and Water Storage Tanks Used in the
not less than 20 psi (138 kPa) when tested as specified in
Testing of Hydraulic Cements and Concretes
Section 9.
3. Terminology
5.4 Freeze-Thaw Stability—The bond strength shall be not
less than 20 psi (138 kPa) when tested as specified in Section
3.1 Definitions—For definitions relating to gypsum and
11.
related building materials and systems, see Terminology C11.
5.5 Bond Strength—Bondstrengthofafreshsampleora30
4. Physical Properties
day old sample shall be not less than 20 psi (138 kPa) when
tested as specified in Section 12.
4.1 General—The bonding compound shall be a film form-
ing, non-oxidizing, non-toxic, non-flammable composition
6. Sampling
6.1 Take a sample of not less than 1 kg from each shipment
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This specification is under the jurisdiction of ASTM Committee C11 on
or consignment for analysis and tests. Except in special cases,
GypsumandRelatedBuildingMaterialsandSystemsandisthedirectresponsibility
take the sample from not less than three separate containers,
of Subcommittee C11.02 on Specifications and Test Methods for Accessories and
chosen at random. In addition, take samples from containers
Related Products.
Current edition approved Oct. 10, 1995. Published December 1995. Originally
that appear to be nonrepresentative, and test separately. Imme-
approved in 1988. Last previous edition approved in 1995 as C 631–95.
diately place the samples in airtight glass containers and
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
transport to the testing laboratory in these containers. Take
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on precautions to reduce evaporation or drying to a minimum.
the ASTM website.
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C 631 – 95a (2004)
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