TM 1-1500-204-23-11
installed. The pleats need to be placed in strategic
components require envelope bagging because they
locations that ensure the vacuum bag material will
can be very dificult to seal and insuficient vacuum
not be stretched too far and burst upon vacuum
is achieved using a single-sided bag.
application. In addition, great care must be taken
when using the envelope-bagging process to prevent
(1) Facilities, Equipment, and Materials. The
damaging the repair part. Vacuum pressure can easily
following items are required to perform envelope bag-
crush core and collapse edge structure if the part
ging procedures: vacuum source (venturi or vacuum
is not bagged properly or is inadequately supported
pump), vacuum hoses, vacuum port, vacuum gage,
in the vacuum bag. On thin skin components, it
self-vacuum ittings, caul plate, temperature/vacuum
may be necessary to locate the vacuum ports off
controller, heat blanket (as needed), thermocouples,
the structure to eliminate the possibility of damaging
scissors, straightedge or tape measure, marking pen,
the skin when vacuum is applied. This can be
fairing bars, edge supports, caul plates, utility knife,
accomplished by fabricating a vacuum bag extension
peel ply, non-porous release ilm, porous release ilm,
or lap. Tooling may also need to be fabricated to
bleeder plies, breather cloth, bagging ilm, vacuum
protect the part before the envelope-bagging process
bag sealant tape, and lash breaker tape.
can begin. Parts can be damaged from the application
of vacuum pressure when using the envelope bagging
process. Tooling aids must be fabricated to prevent
part damage. Refer to system speciic technical
Parts can be damaged from the application
manual for tooling and vacuum pressure requirements.
of vacuum pressure when using the enve-
Figure 6-31 illustrates the procedure for envelope
lope bagging process. Tooling aids must be
bagging a component that can be placed onto a
fabricated to prevent part damage. Refer to
worktable.
system speciic technical manual for tooling
and vacuum pressure requirements.
(2) Procedure. When envelope bagging, many
part conigurations will require the bag be pleated when
Figure 6-31. Envelope Bagging a Part on a Worktable
