TO 35-1-3 - Robins Air Force Base

TO 35-1-3
3.11 MAINTENANCE STAND RAILS AND RAIL HOLD-
ERS.
degree FORMIT® spray wand or equivalent to apply CPC
through the drain holes the entire length of the stand rails.
3.12 HOLLOW STRUCTURAL MEMBERS.
Do not drill drain holes in weldments seams or beads.
NOTE
Using activities that find standing or entrapped water
in equipment due to the lack of drainage should forward
this information to the responsible equipment
specialist or system engineer for action through Material
Deficiency Reporting channels as outlined in
TO 00-35D-54.
3.11.1 Drain Holes. Field units are authorized to drill necessary
drain holes at the lowest point on the maintenance
stands rail holders to avoid water from collecting in the holders.
3.11.2 Drain Hole Corrosion Prevention and Treatment.
Paint the edges of the drain holes after drilling to prevent
corrosion from occurring around the holes.
3.11.2.1 Since repeated installation and removal of the rail
into the rail holder will result in damage to the paint on both
items, additional protection is required on the ID of the holder
and the OD of the bottom part of the rail.
3.11.2.2 Coat the ID of the rail holder and the bottom part of
the stand rail that are inserted into the holder with solid film
lubricant conforming to MIL-L-23398 or MIL-PRF-46147 (air
curing types). The solid film lubricant shall be applied and
completely cured prior to assembly.
3.11.2.3 To prevent corrosion, CPC, MIL-PRF-16173, Grade
4, or MIL-PRF-81309, Type II should be applied periodically
to the exterior bottom of the rail and interior of the holder and
the interior of the stand rails. Use the appropriate length 360
3.12.1 Drainage for Closed Hollow Members, When
Open Drain Holes are Possible. A completely air tight
weld is required for closed hollow members to prevent condensation
of moisture in the interior surface. To prevent moisture
accumulation from occurring (since it is difficult to obtain
perfect welds), all closed hollow members will have drainage
provisions at the lowest drain-through-drain-to point of the
member, reference Figure 3-2.
3.12.1.1 For horizontal members, drain hole(s) will be provided
on the lower side equally spaced across the hollow
member at an approximately thirty-six inch interval.
3.12.1.2 For vertical members, drain hole(s) will be provided
on bottom end-cap.
3.12.2 Drainage for Closed Hollow Members, When
Open Drain Holes are Not Possible. If a drain hole is not
possible due to design (such as a butt joint with a plate behind
it or two pipes forming a saddle joint) then a drain hole should
be placed at the lowest possible drain-through-drain-to point,
see Figure 3-3. Application of sealant that is formed to direct
the drainage to the drain hole is authorized to facilitate fluid
drainage.
3.12.2.1 The drain hole should not penetrate a weld and must
be approved by the responsible engineering organization.
Since the location of the drain hole could allow water inside
the hollow member insert a removable plug (weld-nut) into the
drain hole. Preferred size of the hole for the weld-nut is 0.50
inch, minimum size is 0.375 inch. Length will be as determined
by the hollow member wall thickness. A suggested
source of supply for the weld nuts is available from the Molly
Division of USM Corp., 504 Mt. Laurel Avenue, Temple,
Pennsylvania 19560 or any Chevrolet Truck Parts Department.
Figure 3-2. Hollow Member Drain Hole Configuration
3-7