TM 1-1500-204-23-11
(p) Place vacuum connector base and vac-
(x) Cover the entire rigid box with two layers
uum gage base on pads located on top
of breather cloth.
of breather plies. Remove the back-
ing paper from the vacuum bag sealant
(y) Place vacuum connector base and vac-
tape and place inner vacuum bag mate-
uum gage base on pads located on top
rial over the layup and press into vac-
of breather plies. Place outer vacuum
uum bag sealant to seal the bag. Make
bag material over the breather on the
small slits in the bagging ilm over the
rigid box and press into vacuum bag
two bases and install vacuum connec-
sealant to seal the bag. Make small slits
tor and vacuum gage.
in the bagging ilm over the two bases
and install vacuum connector and vac-
(q) Connect the vacuum source to the inner
uum gage.
bag. (A dedicated vacuum pump is
recommended to ensure vacuum level
(z) Apply vacuum to the outer box as fol-
integrity.) Apply a minimum of 20 inches
lows:
of mercury vacuum.
Remove vacuum source to inner
1
(r)
Make sure there are no wrinkles in the
bag ensuring a minimum of 25
vacuum bag over the laminate. Wrin-
inches of mercury vacuum is
kles will leave markoff on the laminate.
retained in the inner bag.
Apply vacuum to the outer box.
2
When the vacuum level in the outer
3
To ensure the integrity of the repair, it is
box is within 1 inch Hg of the inner
critical to complete the inner bag leak check
bag, reapply vacuum to the inner
procedure.
bag.
(s) Disconnect vacuum source and take
(aa) Smooth wrinkles in the outer bag as air
initial reading on inner vacuum bag
is evacuated. Ensure a minimum of 20
gage to check for leaks. Wait 5 minutes
inches of mercury vacuum is obtained
and take inal reading on inner vacuum
on the outer bag vacuum gage without
bag gage. The vacuum level must not
audible leaks. If a minimum of 20 inches
drop more than 5 inches of mercury
of mercury cannot be obtained on the
over a ive minute interval. Repair or
outer vacuum bag and/or audible leaks
replace bag until bag can meet leak
cannot be eliminated, repair or replace
check requirements.
outer bag using new bagging materials.
(t)
If a leak is found, work the bag into the
sealant tape and look for tears/punc-
(ab) Debulk the patch per system speciic
tures. If necessary, replace the bag
technical manual, engineering guideline
until the leak rate meets the speciied
or table 7-6.
requirement.
With vacuum applied to both bags,
1
(u) Reapply vacuum to the bag after the
heat laminate to the required
leak check has been completed.
debulk temperature at a rate of 3-5
F per minute. Ensure a vacuum of
NOTE
20 inches of mercury minimum is
maintained in both bags.
If using the double vacuum tool, before closing
the outer box, verify the O-ring seal and mating
Upon the coldest thermocouple
2
surfaces are clean and the O-ring is properly
reaching the minimum debulk tem-
retained inside the outer box groove.
perature, begin a timed soak. Con-
tinuously monitor and record all
(v) Center the rigid box over the laminate.
thermocouples to ensure the tem-
perature range is maintained dur-
(w) If necessary, place a bead of vacuum
ing the soak period.
bag sealant just outside of the perime-
ter of the rigid box on top of the inner
vacuum bag material.
7-109
