ASTM C790-90

Guide for Use of Latex Sealants (Withdrawn 1992)

General Information

• Status: Withdrawn
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants

Standards Content (Sample)

AMERICAN SOCIETY FOR TESTING AND MATERIALS
#]b Designation: c 790 - 90
1916 Race SI. Philadelphia. Pa. 19103
Repiinlod Irorn lhe Annual Ewk of ASTM Standards. Copyrighl ASTM
II no1 tisled in lhe cuirenl combined index. will appear in lhe nexl ediiion
Standard Guide for
Use of Latex Sealants'
This standard is issued under the fixed designation C 790; 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 (e) indicates an editorial change since the last revision or reapproval.
5. Substrate Surface Preparation
1. Scope
5.1 Cleanliness-Substrate surfaces to be sealed should be
1.1 This guide describes procedures for the selection and
application of latex sealants. Applications where latex seal- sound, dry, free of oils, dust, mortar spatter, release agents,
ants are used include interior and exterior joints of residen- all old caulking, bitumen, flaking or peeling paint, or other
tial and commercial buildings. Sections describing substrate contaminants. Slight substrate dampness can be tolerated.
surface preparation, weather conditions, backing, primers, The manufacturer of the latex sealant should be consulted
gun selection, gunning procedures, painting, clean-up, selec-
concerning the adhesion of its product to substrates con-
tion, and identification are included.
taining special treatments such as protective coatings on
1.2 This standard does not purport to address the safety
metal and waterproofing or water-repellent treatments on
problems associated with its use, It is the responsibility of the
wood or masonry.
tuer of this standard to establish appropriate safity and
5.2 Removal of Contaminants-Dust and dirt should be
health practices and determine the applicability of regulatory
removed by blowing with oil-free compressed air, whisking,
limitations prior to use.
or wiping. For a wet nonporous surface the moisture can be
removed by wiping the area with a clean, dry cloth. For a wet
2. Referenced Documents
porous surface, a drying period of 48 to 72 h is recom-
mended before sealant application, All old sealant, flaking or
2.1 ASTM Standards:
peeling paint, and other contaminants that cannot be wiped
C 7 17 Terminology of Building Seals and Sealants*
or blown away should be removed by scraping, cutting,
C 962 Guide for Use of Elastomeric Joint Sealants'
grinding, or chiseling.
3. Terminology
3.1 Definitions-Refer to Terminology C 7 I7 for defini-
6. Weather and Climate Conditions
tions of the following terms used in this guide:
6.1 Low- Temperature Applicat ion-Low surface tempera-
bond breaker,
ture of substrates decreases the ability of sealants to adhere
joint,
because the surface wetting characteristic of the sealant is
latex sealant,
reduced. The ease of extrudability of latex sealants is also
primer,
reduced at low temperatures. Frost, which can form on the
sealant backing,
substrate surface during periods of high humidity with-
substrate, and
temperatures below 40'F (4"C), prevents optimum adhesion
tooling.
of the sealant. Frost should be removed and the surface
3.2 Descriptions of Terms SpecHc to This Standard:
aliowed to warm prior to application. Latex sealants should
3.2.1 extrudabilip-force required to produce sealant
not be applied when freezing temperatures are anticipated
flow through an orifice.
within 24 h after application. For these reasons, sealant
3.2.2 tack-sticky or adhesive quality of the surface of
should not be applied at surface and air temperatures below
applied sealant.
4a"F (4°C) or when temperatures may fall below 32°F (OOC)
within 24 h. Store the sealant above the manufacturer's
4. Significance and Us0
recommended minimum temperature until just before use,
4.1 This guide provides information and guidelines for
6.2 Hot- Weather Application-Hot-weather application
consideration by the applicator of latex sealants. Section 6
will shorten the tack-free time and cure time of the sealant.
provides information on the possible effects caused by
The tooling time wiii also be reduced and therefore shorter
uncontrollable weather and climate conditions. Section 12
runs of sealant may be necessary before tooling is done.
on selection and identification aids the specifier and pur-
6.3 Inclement- Weather Application-Sealing should not
chaser, as well as the applicator, in selection of the appro-
be done immediately before, during, or immediately after a
priate sealant for the application.
rain. However, rain within 8 h after the sealant has become
tack free usually has no serious effect unless there is forceful
w
impingement of flowing water or prolonged hlNX&XL No'
I This gulde is under the juridiction of ASTM Committee C-24 on Building
Seuls and Sedants and is the dir& responsibility of Subcommittee (24.16 on exterior seal
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