back in the days before fusibles, i used elmer's school glue to hold the patches on my husband's army fatigue uniforms. didn't take much on the back, put them in place, then pressed with heavy books on it for awhile. no fingers were abused by pins this way. once sewn in place you didn't know the glue was there, and it came out when washed and the patches were all flat. my 2 cents worth.