Figure 8-62.—Dolly blocks used to shape body panels. NOTE Make  sure  the  surfaces  of  the  spoons, hammers,  and  dollies  are  free  from  scratches and/or  dents.  Surface  defects  on  these  tools will  cause  similar  defects  in  the  sheet  metal they are used on. To remove surface defect on these  tools,  use  a  file  and  fine  grit  sandpaper until you have a smooth surface. With these tools and experience you will be able to remove the dents and creases while restoring the body to a like-new condition. The ease and speed with which you  can  straighten  the  sheet  metal  is  dependent  on starting  the  repair  work  at  the  right  point  and  the correct use of the tools. If this is done, the amount of “dinging” (light tapping of the metal with a hammer) required  to  remove  the  dent  is  reduced  considerably. As  metal  is  dinging  and  formed,  a  certain  amount  of stretching  occurs.  This  causes  additional  work  when nearing  completion  of  the  repair.  Always  remember, when  straightening  a  damaged  panel,  the  damage should be removed in reverse order of how it occurred. REMOVING  DENTS Before attempting any body repairs, scrape off any undercoating or foreign matter located in the area to be repaired.  Dirt  or  undercoating  will  cake  on  the  dolly block.  No  amount  of  hammering  will  produce  a smooth surface when this occurs. Next make sure the outer side is clean to protect the hammer. Without  prior  body  repairing  experience,  a mechanic  will  usually  start  applying  pressure  at  the spot where the panel was struck first and is depressed the  most.  The  CORRECT  METHOD  is  to  apply pressure at the ridge farthest from the point of impact. To  make  the  procedure  clear,  refer  to  the  damaged panel in figure 8-63. Assume  that  the  original  form  of  the  panel  is shown as the dotted line. Point Y is where it was struck, and X is a ridge that was formed last. With the use of a spoon and hammer or mallet, place the spoon on the ridge  (X)  and  strike  it  with  the  hammer.  Aim  your hammer blows directly at the ridge (X). By following the ridge with the spoon and hammer, you will find that the  ridge  will  gradually  disappear  while  the  major portion of the depression at point Y will spring back and very closely resemble the original contour of the panel. Using  a  dolly  block  with  the  same  general curvature as the panel, place it under the panel at point O and strike the dent as shown. In this way, the dolly block acts as a hammer and raises the dented portion to the  original  contour,  as  the  dolly  block  is  gradually moved  toward  point  Z.  The  most  common  mistake made by an inexperienced body repairman is trying to do all the work with one blow of the dolly. All that is necessary of the hammer or dolly is to press the metal back into position. A number of light blows with the hammer or dolly is better than a few heavy ones. Heavy blows result in the metal stretching excessively during the straightening process. This requires that the panel be shrunk later to remove bulges. When   working   with   the   hammer,   apply   blows rapidly  with  a  pulling  action  so  the  hammer  tends  to slide  as  it  contacts  the  metal.  Above  all,  don’t  try  to rush the job by striking the metal too heavily. Figures 8-64 and 8-65 show the procedures for removing dents when   performing   bodywork.   Use   of   a   flat-faced hammer  should  be  confined  to  the  flat  or  nearly  flat surfaces and the outside of curved surfaces. Hammers with  crowned  faces  are  for  use  on  concave  surfaces only. 8-49