TM 5-1940-321-13&P
NOTE:
A complete cure of the glue requires 7 days. The craft may be used after 72
hours. Small patches that are nonstructural require less time; 48 hours is
sufficient.
( 1 ) If the glue appears stringy in the fingertip test, wait 45 seconds and test again. If
the glue does not feel sticky during the fingertip test, it has dried too much and
must be reactivated with solvent. The glue must always be reactivated when the
relative humidity is higher than 75 percent. When gluing large patches or
patches which are difficult to apply, reactivate the glue in small sections as the
application progresses.
( 2 ) Reactivate glue by applying a thin coating of the correct solvent using a clean
shop towel. Do not scrub the surface with solvent. Simply apply a thin, even
coating of solvent. After reactivating with solvent, it is necessary to wait before
joining pieces to be glued. The solvent will take a minute or so to soften the
glue. The glue may then be stringy in the fingertip test. Additional time will allow
glue to reach the correct stage for joining. The correct stage is indicated by the
fingertip test. The glue should sticky to the touch, but strings of glue should not
pull away from the surfaces.
( 3 ) Glazed glue must also be reactivated. Be alert for signs of the glue glazing.
Glazing is present when the applied glue turns white. Glazing occurs when the
relative humidity is too high, usually outdoors and glazing can occur indoors if
an open door allows a humid draft to blow on the applied glue.
( 4 ) When joining the pieces, ensure that they are correctly aligned. Large patches
may be rolled up for easier handling and positioning. When patches are rolled,
carefully align the edge of the patch with the surface to be patched as shown in
figure F-10. Push the patch down lightly at first, and slowly unroll the patch while
lightly pressing it into place.
( 5 ) Avoid puckers, creases, and blisters in the fabric. If a crease, pucker, or blister
appears, lift that area and reapply the patch lightly. When the two pieces of
fabric are in position, use a towel dampened with solvent to rub and press the
two pieces together as shown in figure C-11. The possibility of creases and
puckers is reduced if you rub from the center to the edge.
( 6 ) For small patches, the two pieces must then be firmly bonded into contact with a
boning knife ( PN 7034). Figure C-12 illustrates the boning operation. Begin
boning in the center of the patch or fabric area. Work from the center to the
outside in all directions. This technique minimizes puckers and blisters. When
boning, apply heavy pressure to firmly adhere the two pieces of fabric. Bone the
entire surface. When sufficient pressure is applied to the boning knife, the
surface of the fabric will appear slightly marked. These marks can be removed
by wiping the patch with solvent.
F-14
