ARMY TM 5-6115-612-34 NAVY AG-320B0-MME-000 c     Requirements. (1) Equipment.    An    approved    metalizing    gun designed  to  provide  automatic  gas  pressure  and  wirer feed control. (2) Coating materials. (a) Bond     coat     Shall     be     an     approved martensitic chromium corrosion resistant steel or a nickel aluminum composite wire (item 11, appx B) (b) Coating   alloy   Shall   be   an   approved aluminum alloy wire (item 14, appx B) (c) Resin sealer coat (Item 105, appx B) d Procedure WARNING Toxic solvent Is used for general cleaning Illness or skin damage may be caused by prolonged breathing    of    solvent    fumes    or    excessive    skin contact   with   the   liquid   Ensure   there   is   adequate ventilation  and  avoid  open  flame  or  sparks  when using flammable solvent (1) Cleaning  Parts  shall  be  thoroughly  cleaned free  from  grease,  oil,  dirt,  or  other  foreign  materials  by vapor  degreasing  or   by   washing   In   petroleum   solvent (item 5, appx B) or other suitable solvent (2) Masking Parts shall be masked as required to protect areas not designated to be coated Masks may be   steel,   brass,   or   other   suitable   materials   properly protected against adherence of the sprayed coating (3) Surface  conditioning  Grit  blast  the  masked parts  sufficiently  to  remove  all  metallic  luster,  excessive blasting snail be avoided (a) Care must be taken to prevent contamination   of   the   prepared   surfaces   by   contact   or other  means.  If  necessary  to  handle  the  prepared  part, clean,  lint-free  gloves  (Item  6,  appx  B)  must  be  used Parts  shall  be  spray  coated  as  soon  as  possible,  but  In no  case  longer  than  2  hours  after  surfaces  have  been prepared for coating If this time is exceeded, repeat step (3) (b) Wipe  grit  blasted  surfaces  with  clean, lint-free  rag  (item  7,  appx  B)  dampened  with  acetone (item  1,  appx  B)  or  other  suitable  solvent  just  prior  to spraying (4) Spray coating. (a) Place part in fixture designed to permit uniform coverage of areas designated to be coated (b) Preheat the cleaned and masked parts to 175-200° F (79-93° C) (c) Apply  the  bond  coat  onto  designated areas to a thickness of 0 002-0 007 in (0.05-0 18 mm) (d) As   soon   as   spraying   operations   are started,  introduce  a  stream  of  air  onto  the  part  being coated  to  maintain  a  part  temperature  120-250°  F  (40- 121° C) Maintain cooling air blast throughout all coating operations. (e) Spray   the   aluminum   alloy   (item   14, appx  B)  coating  onto  the  designated  areas  to  a  total thickness  sufficient  to  meet  drawing  requirements  after finish machining. (f) The spray coating must impinge on the surface  to  be  coated  at  an  angle  of  75-105  degrees (1.31-1.83 radians) (g) Remove masking in a manner that will avoid damage to the sprayed coating (h) Impregnate the aluminum alloy coating completely with an approved silicone resin coating (item 15,  appx  B)  Completely  impregnation  is  accomplished when, 30 minutes after application,  resin is still present on  the  coated  surfaces  Bake  the  silicone  resin  coated part by heating to 140-160° F (60-73° C) holding at heat for  25  to  30  minutes,    heating  to  440-460°  F  (226-238° C), holding at heat for 55 to 65 minutes, heating to 575- 625° F (301-331 o C) and holding at heat for 165 to 195 min- utes, and cooling In air to room temperature e QualityThe sprayed coating shall be adherent to the basis material and shall have a uniform surface free from blisters, chips, or other objectionable imperfections not readily removable by finishing operations. (1) Examination  shall  show  the  coatings  to  be free from cracks and massive oxides, and contamination at the interface between the coating and substrate. (2) Quadrant   cases   Hairline   cracking   of   the coating at the permanent (non-disassembled) split line is acceptable   provided   there   is   no   evidence   of   bond separation Change 4    14-7