TM 10-3930-664-24 (a) Thoroughly  clean  all  existing  sealant  and  dirt  that  may  remain  on  switch.    Replace  the  switch  if corroded.  The sealant must have a clean surface to adhere to or there will not be an effective seal. (b) After switch is cleaned and reassembled or replaced, apply sealant. Cover the switch and terminals completely   with   sealant.      Press   sealant   into   and   around   the   terminals   to   ensure   complete coverage. (c) Sealant will set in 15-30 minutes depending on temperature and humidity. (3) Loctite  Retaining  and  Sealing  Compounds.    These  compounds  will  resist  solvents,  heat,  shock  and vibration.  They provide a positive seal against leakage and sheer strength resistance to loosening when used in the assembly of threaded, slipfit or press fitted parts.  Use the grade of Loctite specified. Once cured,  these  compounds  have  an  operating  temperature  range  of  -65  to  300  degrees  F  (-54  to  149 degrees C), and will resist attack by oils, chemicals, hydraulic fluids and solvents.  Do not use  Loctite where other retaining means are provided, such as lock wires, lock washers, lockplates and fasteners. Do  not  substitute  grades  or  usage  unless  specified.    Do  not  use  Loctite  on  items  that  need  frequent servicing, brass fittings or plugs, or when operating temperatures exceed 300 degrees F (149 degrees C). (Example: Engine exhaust systems.) Loctite is applied as follows: (a) Threadlock Adhesives.  Primers are not required with threadlock adhesives, but if used will speed up the cure and act as a  cleaner.  Surface  preparation  depends  on  type  of  metal  and  purpose  of application.  In general, most surfaces must be cleaned thoroughly. (b) Apply  Loctite  to  bolts  and  studs  by  filling  full  length  of  thread  with  one  strip  in  diameters  up  to  1 inch,  two  strips,  180  degrees  apart,  on  diameters  up  to  2  inches,  and  three  strips,  120  degrees apart, on diameters over 2 inches.  Apply one strip into tapped holes.  For blind hole applications, apply   enough   Loctite   to   fill   the   bottom   2   to   3   threads   of   engagement,   then   insert   stud.      If engagement length exceeds one diameter, use proportionally more Loctite.  For non-seated studs (studs that to deeper in hole than required) turn stud one turn deeper than required.  After bubbling stops, apply a ring of Loctite around stud at top of hole, then back stud to required height.  Loctite will set in 10 minutes to 2 hours.  Temperature and humidity affect drying time. (c) Plastic Gasket.  Plastic gasket is used as a seal on large close fitting metal parts.  Mating surfaces must be clean and degreased.  Spread an even coat (0.061 cubic inch per 40 square inches) on one of the mating surfaces.  Assemble  and tighten bolts.  Plastic gasket will dry in approximately 12-24 hours.  Temperature and humidity affect drying time. 1-39