ASTM C419-20

Standard Practice for Making and Curing Test Specimens of Mastic Thermal Insulation Coatings

SIGNIFICANCE AND USE
5.1 The method of preparation of test specimens of mastic thermal insulation coatings will have an impact upon values obtained during testing. Testing laboratories shall follow this practice to help ensure the reproducibility of test methods for which a cured sheet or film of a mastic thermal insulation coating is required.
SCOPE
1.1 This practice covers the preparation of specimens of mastics and coatings in the form of cured sheets or films that are used in other procedures for evaluation of physical properties.  
1.2 Three procedures are described for casting and curing (Note 1) mastics and coatings of all types for thermal insulation. When reinforcing mesh in recommended by the mastics and coatings manufacturer, test specimens shall be prepared using reinforcing mesh.
Note 1: The term “cure” is used primarily to denote the condition that develops as the result of loss of volatile matter but also to denote possible subsequent changes in chemical or physical properties due to crosslinking.  
1.2.1 Procedure A is intended to provide a specimen of controlled thickness applied to the intended insulation for field use and equivalent in other respects to that obtainable under field application conditions.  
1.2.2 Procedure B is intended to provide a free-film specimen of controlled thickness having smooth surfaces on both sides. This type is required for some types of physical testing.  
1.2.3 Procedure C is intended to provide a free-film specimen of controlled thickness having one smooth surface (as field applied).  
1.3 The procedures of this practice are not intended for the evaluation of application properties. These are covered in Test Methods C461 and Guide C647.  
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

General Information

• Status: Published
• Publication Date: 29-Feb-2020
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.33 - Insulation Finishes and Moisture

Relations

• Replaces: ASTM C419-08(2013) - Standard Practice for Making and Curing Test Specimens of Mastic Thermal Insulation Coatings
• Effective Date: 01-Mar-2020
• Refers: ASTM C168-24 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Apr-2024
• Refers: ASTM C647-19 - Standard Guide to Properties and Tests of Mastics and Coating Finishes for Thermal Insulation
• Effective Date: 01-Mar-2019
• Refers: ASTM D6/D6M-95(2018) - Standard Test Method for Loss on Heating of Oil and Asphaltic Compounds
• Effective Date: 01-May-2018
• Refers: ASTM C168-18 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Apr-2018
• Refers: ASTM C168-17 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jun-2017
• Refers: ASTM C461-81(2015) - Standard Test Methods for Mastics and Coatings Used With Thermal Insulation
• Effective Date: 01-Dec-2015
• Refers: ASTM C168-15a - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Oct-2015
• Refers: ASTM C168-15 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jun-2015
• Refers: ASTM C647-08(2013) - Standard Guide to Properties and Tests of Mastics and Coating Finishes for Thermal Insulation
• Effective Date: 01-Nov-2013
• Refers: ASTM C168-13 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Apr-2013
• Refers: ASTM C533-13 - Standard Specification for Calcium Silicate Block and Pipe Thermal Insulation
• Effective Date: 01-Mar-2013
• Refers: ASTM C533-11 - Standard Specification for Calcium Silicate Block and Pipe Thermal Insulation
• Effective Date: 15-Sep-2011
• Refers: ASTM D6/D6M-95(2011)e1 - Standard Test Method for Loss on Heating of Oil and Asphaltic Compounds
• Effective Date: 01-Jan-2011
• Refers: ASTM C168-10 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jan-2010

Overview

ASTM C419-20: Standard Practice for Making and Curing Test Specimens of Mastic Thermal Insulation Coatings sets forth procedures for the preparation and curing of mastic and coating specimens in the form of cured sheets or films. These test specimens are essential for evaluating the physical properties of mastic thermal insulation coatings in a controlled, reproducible manner. By adhering to this standard, testing laboratories and manufacturers can ensure consistency and reliability in test results, which is vital for quality assurance and product development in the thermal insulation industry.

Key Topics

• Specimen Preparation: ASTM C419-20 details three procedures for casting and curing specimens:

  • Procedure A (Adhered Film): Produces a specimen with controlled thickness applied to the intended insulation material, simulating field installation.
  • Procedure B (Free Film, Both Sides Smooth): Provides a self-supporting film with smooth surfaces on both sides, used for specific physical tests.
  • Procedure C (Free Film, One Side Smooth): Yields a free film with one smooth surface, representing typical field application.

• Use of Reinforcing Mesh: When the mastic or coating manufacturer recommends reinforcing mesh, it must be incorporated into the test specimens to accurately reflect real-world applications.

• Curing Conditions: Guidance is given for both initial ambient-temperature curing and subsequent oven curing, ensuring specimens achieve the required degree of cure for dependable testing.

• Degree of Cure Determination: The standard addresses methods for determining the degree of cure, primarily through loss of volatile content and referencing established ASTM test methods.

• Measurement and Reporting: Requirements include measuring dry thickness, removing and cleaning specimens post-curing, and documenting key details such as number of coats, primer or membrane use, and deviations from the standard procedure.

Applications

ASTM C419-20 is primarily used in the following scenarios:

• Laboratory Testing: Prepares uniform test specimens for evaluating the physical properties (e.g., strength, adhesion, thermal resistance) of mastic thermal insulation coatings under controlled conditions.
• Quality Control: Ensures manufacturer and third-party testing are comparable and reliable, promoting consistent product quality.
• Product Research and Development: Facilitates comparison of new and existing mastic formulations and coatings, expediting innovation in thermal insulation technologies.
• Specification Compliance: Assists manufacturers and specifiers in demonstrating that products meet industry or project requirements by supporting accurate and repeatable testing results.

This practice is not intended for application property evaluation (such as workability or field application performance); those aspects are covered by separate ASTM standards referenced below.

Related Standards

ASTM C419-20 is part of a broader framework for evaluating thermal insulation materials and coatings. Key related standards include:

• ASTM C168 - Terminology Relating to Thermal Insulation
• ASTM C461 - Test Methods for Mastics and Coatings Used With Thermal Insulation
• ASTM C533 - Specification for Calcium Silicate Block and Pipe Thermal Insulation
• ASTM C647 - Guide to Properties and Tests of Mastics and Coating Finishes for Thermal Insulation
• ASTM D6/D6M - Test Method for Loss on Heating of Oil and Asphaltic Compounds

Understanding these standards in conjunction with ASTM C419-20 supports comprehensive assessment and documentation of mastic thermal insulation coatings.

Practical Value

Following ASTM C419-20 ensures reproducible laboratory specimen preparation, a foundational step in reliable product testing for the thermal insulation industry. By standardizing how mastic thermal insulation coating specimens are made and cured, organizations can ensure consistency, facilitate quality assurance, support regulatory compliance, and promote innovation in insulation systems.

Standards Content (Sample)

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: C419 − 20
Standard Practice for
Making and Curing Test Specimens of Mastic Thermal
Insulation Coatings
This standard is issued under the fixed designation C419; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This practice covers the preparation of specimens of
ization established in the Decision on Principles for the
mastics and coatings in the form of cured sheets or films that
Development of International Standards, Guides and Recom-
are used in other procedures for evaluation of physical prop-
mendations issued by the World Trade Organization Technical
erties.
Barriers to Trade (TBT) Committee.
1.2 Three procedures are described for casting and curing
(Note 1) mastics and coatings of all types for thermal insula-
2. Referenced Documents
tion. When reinforcing mesh in recommended by the mastics
2.1 ASTM Standards:
and coatings manufacturer, test specimens shall be prepared
C168 Terminology Relating to Thermal Insulation
using reinforcing mesh.
C461 Test Methods for Mastics and Coatings Used With
NOTE 1—The term “cure” is used primarily to denote the condition that
Thermal Insulation
develops as the result of loss of volatile matter but also to denote possible
C533 Specification for Calcium Silicate Block and Pipe
subsequentchangesinchemicalorphysicalpropertiesduetocrosslinking.
Thermal Insulation
1.2.1 Procedure A is intended to provide a specimen of
C647 Guide to Properties and Tests of Mastics and Coating
controlled thickness applied to the intended insulation for field
Finishes for Thermal Insulation
use and equivalent in other respects to that obtainable under
D6/D6M Test Method for Loss on Heating of Oil and
field application conditions.
Asphaltic Compounds
1.2.2 Procedure B is intended to provide a free-film speci-
men of controlled thickness having smooth surfaces on both
3. Terminology
sides. This type is required for some types of physical testing.
3.1 Definitions—For definitions used in this practice see
1.2.3 Procedure C is intended to provide a free-film speci-
Terminology C168.
men of controlled thickness having one smooth surface (as
field applied).
4. Summary of Practice
1.3 The procedures of this practice are not intended for the
4.1 Mastics and coatings are applied by a metal blade to
evaluation of application properties. These are covered in Test
thermal insulation backing material in a thickness regulated by
Methods C461 and Guide C647.
guide bars. Moderate heat is applied to the specimens to dry or
1.4 The values stated in inch-pound units are to be regarded
otherwise cure them.
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
5. Significance and Use
and are not considered standard.
5.1 The method of preparation of test specimens of mastic
1.5 This standard does not purport to address all of the
thermal insulation coatings will have an impact upon values
safety concerns, if any, associated with its use. It is the
obtained during testing. Testing laboratories shall follow this
responsibility of the user of this standard to establish appro-
practice to help ensure the reproducibility of test methods for
priate safety, health, and environmental practices and deter-
which a cured sheet or film of a mastic thermal insulation
mine the applicability of regulatory limitations prior to use.
coating is required.
This practice is under the jurisdiction of ASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation
Finishes and Moisture. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2020. Published April 2020. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1958. Last previous edition approved in 2013 as C419 – 08 (2013). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/C0419-20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C419 − 20
6. Apparatus depressions, until a coat of uniform thickness extending from
end to end of the specimen covers the entire space between the
6.1 Guide Bars—Two rectangular steel bars of thickness
guide bars. Remove the guide bars without disturbing the wet
equal to the desired wet thickness of the applied mastic or
specimen.
coating. The guide bars shall be equal in length to the total
length of the specimens. Guide bars with mechanical means of
7.5 Procedure B (Free Film)—For the determination of
holding the bars in position during preparation of the test
degree of cure as described in 8.1.2, prepare one extra
specimen such as projecting pins on the lower surface are
specimen in addition to the number required by the other
helpful.
procedures in which they are to be used. Place a sheet of the
release film on the backing block or other suitable hard smooth
6.2 Strike-Off Bar—A flat strip of rigid metal, not less than
surface so that the release surface faces upward, away from the
2 in. (51 mm) greater in length than the width of the specimen.
backing block. Place and secure guide bars of thickness equal
One edge shall be smooth and straight.
to the desired wet mastic thickness on the release film along
6.3 Leveling Roller—One section of straight 1 ⁄2-in. (38-
each of the long edges. Fill the area between the guide bars
mm) stainless steel pipe or any other convenient cylindrical
withmasticandsmoothoutwithatroweltoalevelabout0.063
leveling tool. The tool shall have a smooth surface. Minimum
in. (1.6 mm) above the guide bars. Place on the freshly applied
length shall be 2 in. (51 mm) longer than the width of the
mastic another sheet of release film with the release surface
specimen.
facing the mastic, in the following manner: Place a short edge
6.4 Backing Material—Unless otherwise specified by the
of the release film at one end of the mastic-filled area and
procedure for the test to be made, the backing for the specimen
gradually roll the film into the wet mastic, using the leveling
shall consist of commercial block-type calcium silicate insula-
roller. Take care to prevent formation of air pockets, or
tion meeting the requirements of Specification C533 and
bubbles, under the film. When firmly in contact with the
measuring 2 by 18 by 24 in. (51 by 457 by 610 mm). The mastic, roll out the film-covered mastic until its thickness
backing block shall be prepared by assembling not more than
matches that of the guide bars. Then remove the guide bars
three blocks of smaller dimensions by the use of suitable withoutdisturbingthethicknessofthespecimenortheposition
adhesive or pins, in such a manner as to form a solid, rigid
of the film. A c
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C419 − 08 (Reapproved 2013) C419 − 20
Standard Practice for
Making and Curing Test Specimens of Mastic Thermal
Insulation Coatings
This standard is issued under the fixed designation C419; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers the preparation of specimens of mastics and coatings in the form of cured sheets or films that may be
are used in other procedures for evaluation of physical properties.
1.2 Three procedures are described for casting and curing (Note 1) mastics and coatings of all types for thermal insulation.
When reinforcing mesh in recommended by the mastics and coatings manufacturer, test specimens shall be prepared using
reinforcing mesh.
NOTE 1—The term “cure” is used primarily to denote the condition that develops as the result of loss of volatile matter but also to denote possible
subsequent changes in chemical or physical properties due to crosslinking.
1.2.1 Procedure A is intended to provide a specimen of controlled thickness applied to insulation, the intended insulation for
field use and equivalent in other respects to that obtainable under field application conditions. The thermal insulation intended for
field use may be specified as the backing.
1.2.2 Procedure B is intended to provide a free-film specimen of controlled thickness having smooth surfaces on both sides. This
type is required for some types of physical testing.
1.2.3 Procedure C is intended to provide a free-film specimen of controlled thickness having one smooth surface (as field
applied).
1.3 The procedures of this practice are not intended for the evaluation of application properties. These are covered in Test
Methods C461 and Guide C647.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
C168 Terminology Relating to Thermal Insulation
C461 Test Methods for Mastics and Coatings Used With Thermal Insulation
C533 Specification for Calcium Silicate Block and Pipe Thermal Insulation
C647 Guide to Properties and Tests of Mastics and Coating Finishes for Thermal Insulation
D6/D6M Test Method for Loss on Heating of Oil and Asphaltic Compounds
3. Terminology
3.1 Definitions—For definitions used in this practice see Terminology C168.
This practice is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation Finishes
and Moisture.
Current edition approved Nov. 1, 2013March 1, 2020. Published March 2014April 2020. Originally approved in 1958. Last previous edition approved in 20082013 as
C419 – 08.C419 – 08 (2013). DOI: 10.1520/C0419-08R13.10.1520/C0419-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C419 − 20
4. Summary of Practice
4.1 Mastics and coatings are applied by a metal blade to thermal insulation backing material in a thickness regulated by guide
bars. Moderate heat is applied to the specimens to dry or otherwise cure them.
5. Significance and Use
5.1 The method of preparation of test specimens of mastic thermal insulation coatings canwill have an impact upon values
obtained during testing. Testing laboratories shouldshall follow this practice to help ensure the reproducibility of test methods for
which a cured sheet or film of a mastic thermal insulation coating is required.
6. Apparatus
6.1 Guide Bars—Two rectangular steel bars of thickness equal to the desired wet thickness of the applied mastic or coating. The
guide bars shall be equal in length to the total length of the specimens. For use on relatively soft backing material, the guide bars
may be equipped with pins projecting from the lower surface at each end, which can be forced into the backing to hold the bars
in position during preparation of the test specimen.Guide bars with mechanical means of holding the bars in position during
preparation of the test specimen such as projecting pins on the lower surface are helpful.
6.2 Strike-Off Bar—A flat strip of rigid metal, not less than 2 in. (51 mm) greater in length than the width of the specimen. One
edge shall be smooth and straight.
6.3 Leveling Roller—One section of straight 1 ⁄2-in. (38-mm) stainless steel pipe or any other convenient cylindrical leveling
tool. The tool shall have a smooth surface. Minimum length shall be 2 in. (51 mm) longer than the width of the specimen.
6.4 Backing Material—Unless otherwise specified by the procedure for the test to be made, the backing for the specimen shall
consist of commercial block-type calcium silicate insulation meeting the requirements of Specification C533 and measuring 2 by
18 by 24 in. (51 by 457 by 610 mm). The backing block mayshall be prepared by assembling not more than three blocks of smaller
dimensions by the use of suitable adhesive or pins, in such a manner as to form a solid, rigid block.
6.5 Release Paper—Film—A smooth, dense white paper coated on one side with dextrin, or other water-soluble gum. Size
shouldpaper or film with a suitable non-soluble release surface such as PTFE or silicone. Size shall be approximately the same as
the backing block.
NOTE 2—Films coated with PTFE or other suitable nonsoluble release agent may be used as an acceptable alternative.
7. Preparation of Test Specimens
7.1 Stir the mastic or coating until uniform throughout the container before removing the sample for specimen preparation.
7.2 Determine the percent volatile matter by weight in accordance with Test Methods C461, for use in calculating the degree
of cure in 8.1.2.
7.3 Unless otherwise specified, lay Lay down films to aspecified nominal wet thickness of 0.125 in. (3.2 mm).thickness.
7.4 Procedure A (Adhered Film)—For the determination of degree of cure as described in 8.1.2, prepare one extra specimen in
addition to the number required by the other procedures in which they are to be used. If a primer or pretreatment of the block is
specified, apply to the test specimen in accordance with the recommendations of the manufacturer of the mastic or coating. Place
and secure guide bars of a thickness equal to the desired wet mastic thickness on the backing material along each of the long edges.
Fill the area between the guide bars with mastic and smooth out with a trowel to a level about 0.063 in. (1.6 mm) above the guide
bars. Place the strike-off bar upon the guide bars at one end of the filled area and move it slowly to the other end of the specimen,
pushing the mastic along the surface of the backing. A see-sawing motion of the strike-off bar will be found to aid in uniform
distribution of the mastic
...