TM 1-1500-204-23-11
Table 6-6.
Common Bonded Repair Errors -- Continued
Results
Common Errors
- Undercured material
Cure temperature too low- or -
- Weak repair
Cure time too short
- Thermal damage to part
Cure temperature too high - or -
- Thermal degradation of repair materials
Failure to exhaust exotherm (two-part adhesive)
- Weak repair
before applying heat
- Excess resin advancement
Storing ilm adhesive/pre-preg at ambient temperature
- Poor low characteristics
- or -
- Weak bond
Using expired shelf life materials
Failure to thaw ilm adhesive/pre-preg before opening - Condensation of moisture on material
sealed bag - or -
- Weak porous repair
Storing ilm adhesive/ pre-preg in unsealed bags
Inadequate drying - or -
- Skin to core unbond/laminate blistering
Failure to dry part before repair
- Weak/porous repair
Improper surface preparation - or -
- Contaminated bond surface
Bond surface contaminated after surface preparation
- Poor bond durability
- Weak bond
6-20. GALVANIC CORROSION OF CARBON COM-
b.
Titanium is the preferred metal to use with carbon
POSITES Aluminum parts will extensively corrode if
iber composites. CRES fasteners are accept-
they are used with carbon iber composites and a
able if authorized in the system speciic technical
protective layer is not included.
manual. Use titanium fasteners if the type of fas-
tener is not speciied in the system speciic tech-
nical manual.
a.
A glass barrier ply must be used any time an
aluminum part is mated to a carbon iber struc-
ture and should be included in the lay-up. Inti-
c.
Fasteners used in carbon iber composites must
mate contact is not required, just an electrical
also be protected to prevent galvanic corrosion.
path so even if steel or titanium separates the alu-
Titanium fasteners are preferred and must be wet
minum and carbon composite, the isolation is still
installed with MIL-PRF-81733 sealant.
required.
6-91/(6-92 blank)
