(a) The rivet stem and collar shall be
In general, trimmed holes are not restricted as to size
or shape, however, those of rectangular, circular,
(b) A slight " f l a s h " caused by the
square and oval and rectangular with round ends
pressure necessary to drive the rivet is acceptable
usually are more desirable as to appearance and ease
(c) The configurations of installed rivets
(c) Clean the interior surface of the un-
with the blind side visible shall be similar to those
damaged facing with emery cloth and a clean lint free
cloth soaked with methyl-ethyl-ketone.
(d) Superficial stretch marks which may
(d) Cut a plug patch plate of the same size as
appear on the rivet are not detrimental to rivet
the trimmed hole using the aluminum facing fur-
strength and are acceptable.
nished with the repair kit.
(e) After stem trimming, stem can be
(e) Cut a section of honeycomb materiel the
checked for tightness by applying a force of ap-
same size as the trimmed hole using the honeycomb
proximately ten pounds (4.5 kg) to the trimmed stem
core furnished with the repair kit.
of the rivet, push steadily; do not strike. If the stem
(f) Fabricate a doubler plate the same shape
is neither pushed out or loose; tightness is
sat is factory.
(g) Drill rivet holes in the doubler plate using
(f) Rivet head gapping shall be checked
a number 30 drill (0.128 - 0.132 inch (0.3251 -
with a 0.002 (0.0051 cm) feeler gage. Rivets with a
0.3353 cm) diameter) and spaced as illustrated in
0.002 (0.0051 cm) gap on more than 40 percent of the
rivet head circumference shall not be acceptable.
Drill matching holes
in the plug patch
(g) A partial gap on a round surface is
plate and panel using the doubler plate as a
acceptable, provided the rivet head bears at
(i) Apply a thin coat of adhesive to the
(l) Apply primer and, after primer is dry,
cleaned interior facing (step (c), above) to the edges
repaint repair area using paint conforming to Federal
of the honeycomb core and to the tack of the plug
Standard 595A, Color Chip X34087.
(3} Repair to honeycomb panel with damage to
(j) Insert the honeycomb core into the
both surfaces. Panel damage which penetrates both
trimmed area of the panel and press firmly in place.
surfaces shall be repaired using the procedure given
Place the plug patch plate in position and press
in paragraph (2), above. Both facings shall be
(k) Secure the patch plate in position using
(4) Repair to damaged honeycomb panel edging
1/8 inch (0.3175 cm) domed head blind rivets (from
(closeouts). Repair damaged panel edging as follows:
repair kit), using procedures given below.
(a) Remove the damaged phenolic edging
1. Hold parts to be riveted tightly together
with a sharp knife to cut away from honeycomb core,
with epoxy or other satisfactory method.
using care to prevent damage to honeycomb core and
2. Insert proper rivet in hole and apply
aluminum facing edge.
with gun (supplied with repair kit) by inserting stem
(b) Cut a section of phenolic edging the
head of rivet in bottom slot in gun pulling head
same size as the damaged area and apply a thin
coat of the two part adhesive to the phenolic
Wet all rivets with sealant (EC 776, 3M Co., or
(c) Press the edging firmly in place nad allow
equivalent) before installation.
to cure for a minimum of 8 hours.
3. Hold gun at right angle to work. Push
(5) Repair to honeycomb floor panel. Repair the
gun against work with just enough force to firmly
damaged floor panel as follows:
seat rivet and to aid in avoiding sheet or other
(a) Trim and clean damaged surface as
described in paragraph (2), above.
4. Pull rivet until stem breaks.
5. Installed blind rivets shall be checked
surface of floor panel only.
per step 8., below, before proceeding.
(c) Fill interior floor surface around repair
6. Trim the broken stem flush with the
patch with epoxy.
(d) After epoxy has hardened, smooth with
7. Firmly press on the installed rivet to
(e) Refinish floor surface.
8. Installed rivets shall be inspected as