Hopper; Hopper Care; Hopper Repair - Thrush Aircraft S2R–T660 Maintenance Manual

Regardless of the materials used in the construction or coating of the hopper, it should be
thoroughly washed after each day's work. Use cold, clean water and any domestic detergent.
Inspect the interior of the hopper daily, for evidence of chemical attack, such as surface roughness or
deterioration of the resin. Look for cracks that may have started in the areas of highest stress, such
as attach points and stiffener center portions. Repairs may then be made at the beginning of the
problem, rather than after it has progressed to a serious degree.
After washing, it is very important that the door and gate be left
open for good ventilation and complete drying. It is good practice to
rinse the hopper with cold water after use with chemicals, even if
the idle period ahead is going to be only a few hours.
Hopper repair may be accomplished as follows:
A. Fiberglass surfaces must be clean, dry and free of oil, wax or other foreign matter. If
chemical erosion is evident, sand rough areas and wash with any good domestic detergent.
Rinse with clean water. Sand all surfaces that are to receive a polyester coating. Use
Ashland Specialty Chemical Company's 7241 T15 AROPOL
for the hopper repair.
B. If damage consists only of surface cracks, excessive abrasion or chemical erosion, sand all
affected surfaces smooth. Extend the prepared surface six inches beyond the damaged
area.
C. If damage consists of cracks or holes extending completely through the wall, sand the
surfaces on both sides deep enough to expose the first layer of cloth.
D. Surface damage requires repairs only to the eroded or cracked side. Damage extending
through the wall requires repairs to both the inner and outer surfaces of the hopper. The
number of layers in either case should equal the original basic wall thickness. (Figure 9-1)
Highly stressed areas, such as attach points, require an extra layer of cloth and mat on
each side, in addition to the basic wall thickness.
9 – 3
THRUSH AIRCRAFT INC - T660 TURBO THRUSH
AIRCRAFT MAINTENANCE MANUAL

HOPPER

HOPPER CARE

HOPPER REPAIR (Figure 9-1)
(Figure 9-2)
* NOTE *
™
polyester resin or equivalent
Effective: 12/17/03