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The repair of Galvanized steel bodies is similar to mild steel dump bodies. The same equipment used to repair steel bodies is the same equipment used to repair galvanized steel, and exists within most repair facilities. The repair and maintenance of Galvanized bodies costs about the same as repairing mild steel and can be accomplished with stick welders and regalvanized with standard torch equipment and zinc stick. There are no big hidden costs to upgrade equipment in the shop at a later time. Sometimes hot dip galvanized coatings are damaged by excessively rough use or damage. Damage may also be the result of welding or flame cutting or excessive abrasion. Where limited areas are damaged, the use of low melting point zinc alloy repair rods or powders, the use of organic zinc rich paint, or the use of sprayed zinc (metallizing) is recommended as a very quick repair to the exposed area. The repair principles and skills required in the repair shop are not special. Most all mechanics have the skills necessary to complete the re-galvanizing quickly and completely. Training and complete competency can be achieved within one to two hours if not already possed. Immediately after welding to repair damaged areas or modifications to attach new components, the mechanic immediately cleans the area to remove all flux, dirt and loose material. Then the mechanic heats the exposed ares to approximately 800 degrees with a rosebud or LP flame torch. The mechanic then applies flux and the low melting zinc alloy stick to the effected area. This repaired galvanized ares is almost as good as the original galvanizing. Mechanics can read ASTM recommended practice A780 "Repair of Damaged Hot Dip Galvanize Coatings" covers acceptable methods of reconditioning the damaged areas. Normally after reading and studing this material a mechanic can effectively complete the repair process with no further training, unlike stainless or aluminum.
In the picture example a 8" steel I-beam was arc welded with flux covered rods and left to weather for 12 years. When this weld is view close up, absolutely no evidence of blistering of the galvanized coat next to the bead. It this weld would be on a painted surface, significant paint coat eruption would be evident for several inches on both sides of the weld. This picture shows the self healing exclusive feature of Hot-dipped galvanizing. The correct procedure for apply a galvanized coating to the weld bead is as follows: After welding is completed; and repaired area is still hot, remove all flux, wire brush, apply zinc based flux, and apply addtional heat with a torch, until the solder is drawn into the weld bead. This same procedure will work on a cold steel surface as the process just requires more heat. Any repair technican who had solder household copper water pipes, presently has the skill necessary to spot galvanize a blimished surface. |
