ASTM C679-87(1997)e1

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
´1
Designation:C679–87(Reapproved1997)
Standard Test Method for
Tack-Free Time of Elastomeric Sealants
This standard is issued under the fixed designation C 679; 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.
This standard has been approved for use by agencies of the Department of Defense.
´ NOTE—Keywords were added editorially in June 1997.
1. Scope 4. Summary of Test Method
1.1 This test method covers a procedure for the determina- 4.1 Thetestconsistsoflightlytouchingasurfaceofacuring
tion of the tack-free time property of single- and multi- sealant with a polyethylene film at regular intervals until the
component elastomeric sealants commonly used for sealing, sealant does not attach itself to the film and the film appears
caulking, and glazing in buildings and related construction. clean when peeled from the surface.
1.2 This test method is applicable to self-leveling and 4.2 More specifically a strip of polyethylene film is placed
non-sag grades of sealant. Sealants requiring slight heating to on the surface of the curing sealant and a 30-g (1.06-oz) weight
facilitate extrusion from the cartridge or gun are also described is placed on the film. The weight is left in place for 30 s, then
by this test method. removed and the polyethylene strip is removed and examined
for sealant attachment to the film. The length of time from
NOTE 1—See Specification C 920C 920 for type and grade definitions.
when the sealant was first applied and tooled into the template
1.3 The values stated in metric units are to be regarded as
until the time the sealant is no longer picked up by the film is
the standard. The values given in parentheses are provided for
called tack-free time.
information purposes only.
4.3 With some sealants, interpretation of the end point is
1.4 This standard does not purport to address all of the
confusing in that a very thin film of sealant or oil will transfer
safety concerns, if any, associated with its use. It is the
to the film. For consistency of data, record the point where the
responsibility of the user of this standard to establish appro-
bulksealantisnolongertransferredtotheplasticbutignorethe
priate safety and health practices and determine the applica-
very thin uniform film of sealant or the plasticizer transferred
bility of regulatory limitations prior to use.
to the plastic test strip.
2. Referenced Documents
5. Significance and Use
2.1 ASTM Standards:
5.1 The tack-free time is a measure of the surface cure time
C 717 Terminology of Building Seals and Sealants
and may generally be correlated to a variety of useful param-
C 920 Specification for Elastomeric Joint Sealants
eters such as the time interval before the sealant (1) resists
damage by touch or light surface contact, (2) resists job-site or
3. Terminology
airborne dirt pick-up, (3) resists impinging rainfall.
3.1 Definitions—See Terminology C 717C 717 for defini-
5.2 The tack-free time is sometimes used as an on-the-job
tions of the following terms used in this test method: caulking,
quality assurance test. A quality product that is consistent and
compound, cure, elastomeric, glazing, non-sag sealant, sealant,
reproducible will generally fall within a maximum and mini-
and self-leveling sealant.
mum tack-free time.
5.3 This test for tack-free time can be used at any tempera-
1 ture and humidity. It is important that if a sealant will be used
This test method is under the jurisdiction of ASTM Committee C-24 on
Building Seals and Sealants and is the direct responsibility of Subcommittee C24.32 in a climate quite different than the standard conditions called
on Chemically Curing Sealants.
out in this test method, then those conditions be used to test the
Current edition approved Nov. 27, 1987. Published September 1988. Originally
sealant.
published as C 679 – 71. Last previous edition C 679 – 71 (1977).
Annual Book of ASTM Standards, Vol 04.07.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
´1
C679–87 (1997)
6. Apparatus 8.3 Prepare at least two specimens for each sealant as
follows: Center the template on the metal plate and carefully
6.1 Cabinet or Room, capable of maintaining a temperature
fill it with sealant avoiding air pockets. Strike off the surface
of 23 6 2°C (73.4 6 3.6°F) and 50 % 6 5 % relative humidity.
flat using a metal straightedge, to a uniform thickness.
6.2 Weight, rectangular, with dimensions of 41 by 19 mm
5 3
(1 ⁄8 in. long by ⁄4 in. wide) and mass of 30 g (1.06 oz).
8.4 Relative Tack-Free Time Unknown. If the relative tack-
free time is unknown, the procedure is to pretest one of the test
NOTE 2—The thickness of the weight should be approximately 6 mm
specimens by lightly touching the surface of the sealant with a
( ⁄4 in.) but planed to a thickness that will provide the 30-g (1.06-oz) mass.
film of polyethylene wrapped over the end of a finger. Touch
6.3 Polyethylene Strips, several (often 6 or more), clear, low
the test piece in accordance with an appropriate time interval
density with dimensions 127 by 25 by 0.15 mm (5 by 1 by
described in 8.5. Try to touch a different place on the surface
0.006 in.).
each time. After the polyethylene wrapped finger is lightly
6.4 Timer, capable of measuring minutes and hours.
touched to the surface of the sealant, it is immediately removed
6.5 Rectangular Plates, several (often 6 or more), rectangu-
and examined to see if sealant was picked up on the polyeth-
lar, approximately 152 by 76 mm (6 by 3 in.), made of
ylene film. When no sealant is picked up on the polyethylene
non-porous material such as tin plated steel or aluminum.
strip, perform the next test as described in 8.6.
6.6 Template, rectangular, of steel, brass or other suitable
material, 3.2 mm ( ⁄8 in.) thick with inside dimensions 95 by 8.5 Time Intervals—If the relative tack-free time is un-
25.4 mm (3 ⁄4 by 1 in.); outside dimensions approximately 120 known, the procedure is to pretest, as in 8.4, one test specimen
by 31 mm (5 ⁄4 by 2 in.).
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