Method for repairing a cracked metal part using repair plugs coated with a surface layer of zinc

A method of repairing a cracked metal part having an outer surface, comprising the steps of;

• providing a series of overlapping blind holes extending from and intersecting a crack in the part;
• fixedly securing a lock in said series of overlapping blind holes;
• providing a hole through said crack in a manner so that said hole overlaps a portion of said lock;
• tapping said hole with a tap;
• threading a repair plug coated with a surface layer of zinc and having a weakened portion intermediate its length in said tapped hole;
• said step of threading said repair plug including the application of a turning torque to a head on said repair plug until said repair plug fails in shear at said weakened point;
• and
• removing any portion of said repair plug extending beyond the outer surface of said part.

A method of repairing a cracked metal wall having an outer surface, comprising the steps of:

• providing a first series of overlapping blind holes extending away from and intersecting a crack in the wall;
• providing a second series of overlapping blind holes extending away from and intersecting said crack;
• fixedly securing a lock in each of said first and second series of overlapping blind holes;
• providing a plurality of overlapping repair plugs, each of which is coated with a surface layer of zinc, in said wall along said crack between said locks;
• and
• removing any portion of each repair plug which extends beyond the outer surface of said wall.

A method of repairing a cracked thin metal part having an outer surface, comprising the steps of:

• providing a hole of diameter no greater than 0.200" in a crack in the part;
• tapping the hole with a tap having more than 27 threads per inch;
• securing a plug coated with a surface layer of zinc and having the same number of threads per inch as the tapped hole in the tapped hole;
• and
• torqueing the plug until the torqueing force exceeds the strength of the plug, whereby a portion of the plug extending beyond the outer surface of the part snaps off.

A method of repairing a cracked thin metal part having an outer surfac,e comprising the steps of:

• providing a first series of overlapping holes intersecting and extending generally perpendicular to a crack in the part;
• providing a second series of overlapping holes intersecting and extending generally perpendicular to the crack;
• fixedly securing a lock in each of the series of overlapping holes;
• providing a hole of diameter no greater than 0.200 inches in the crack between the locks so that the hole overlaps a portion of one of the locks;
• tapping the last-mentioned hole with a tap having more than 27 threads per inch;
• securing a plug which is coated with a surface layer of zinc and having the same number of threads per inch as the tapped hole in the tapped hole;
• and
• torquing the plug until the torquing force exceeds the strength of the plug whereby a portion of the plug extending beyond the outer surface of the part snaps off near the outer surface of the part.