TM  10-8400-203-23 I 2-6. REPAIR   AND   MAINTENANCE   OF   PNEUMATIC   MATTRESSES–Continued (c) Allow the cement to dry at least 10 minutes, then press the two parts of the seam firmly into place. Allow the bonded seam to dry at room temperature 18-24 hours before stitching. (Proper drying will  allow  the  seam  to  develop  optimum  green  strength;  incompletely  dried  cement  will  cause debris to form on the needle). (d) Stitch along the seam, 5/16 ± 1/16 inch (0.79 ± 0.15 cm) in from the outer edge. Start 2 inches ahead of the defective portion of the seam and stitch 2 inches beyond it. (e) Seal the stitch holes with 3 coats of the cement, allowing 10 minutes drying time between coats. When the final coat has dried, dust with talc or mica dust. (f) Allow the sealant to set overnight, then inflate and test for leaks. This may be done by immersing the repaired edge in water, or by applying soapy water. Alternatively, the inflated mattress may be allowed to stand overnight; although this method will not give the location of any leaks that maybe present. f.  Repair  of  Blown-Out  Border  Seams. (1)  Recommended  sewing  machine  equipment.  Use  the  finest  practicable  size  chrome  plated  round point needle. Teflon presser foot, knurled feed dog, Singer needle cooler. Thread may be run over a pad saturated with water. Use no wax, oil, or grease thread lubricant. Avoid high sewing speeds. Stitch Type 301; 8 to 10 stitches per inch. (2)  Repair  procedure.  The  repair  consists  of  cementing  together  the  separated  border  seam,  stitching the seam along the inner edge, and sealing the stitch holes. The detailed procedure is as follows: (a) Open the blown-out seam so that the seam separation extends the full width of the seam, i.e., the separated area is squared off. (b) Prop the seam open and apply a heavy coat of cement to both sides of the open seam. (Excess cement beyond the seam will do no harm). (c) Allow the cement to dry at least 10 minutes, then press the two parts of the seam firmly into place. (Incompletely  dried  cement  will  cause  debris  to  form  on  the  needle.) (d) Stitch along the seam, 5/16 ± 1/16 inch (0.79 ± 0.15 cm) in from the outer edge. Start 2 inches (5.1 cm) ahead of the defective portion of seam and stitch 2 inches (5.1 cm) beyond it. (e)  Seal  the  stitch  holes  with  3  coats  of  cement,  allowing  10  minutes  drying  time  between  coats. When the final coat has dried, dust with talc or mica dust. (f) Allow the sealant to set overnight, then inflate and test for leaks. This maybe done by immersing the repaired edge in water, or by applying soapy water. Alternatively, the inflated mattress may be allowed to stand overnight, although this method will not give the location of any leaks that maybe present. 2-13