YOUR  EQUIPMENT  AND  MATERIALS Selection  of  drafting  equipment  and  materials will  depend  largely  upon  each  of  your  drafting assignments.  Let  your  good  judgment  and common sense guide you in their selection. After some  experience,  you  will  automatically  select proper   equipment   and   materials   as   they   are required.  Until  you  become  proficient,  don’t hesitate  to  seek  the  advice  of  your  drafting supervisor or an experienced draftsman. Assign- ments to staff and support billets within the Naval Construction   Force   (NCF)   will   expose   you   to modern drafting equipment and materials, such as the adjustable drafting board with a drafting machine  attached. Drafting Board As  a  SEABEE  draftsman,  you  will  probably not be able to select your drafting board. Unless the  board  is  new,  it  will  probably  be  marred and  full  of  small  pinholes.  To  obtain  a  smooth drawing surface, you should cover the board with a vinyl material or heavy manila paper. Laminated vinyl  covering  minimizes  pencil  scoring,  is  non- glaring, and is easily kept clean by wiping with a damp cloth. Heavy manila paper will serve the same  purpose,  but  must  be  replaced  when  it becomes  soiled  or  marked  with  use. Drafting Paper Most of the drawings that you will prepare will be drawn on tracing paper, which was described in chapter 2. You will use tracing paper to copy or trace drawings either in pencil or in ink. You will  also  prepare  most  of  your  original  pencil drawings on tracing paper. This type of paper is especially  suited  for  reproduction  of  blueprints. However, it tears easily and becomes soiled after repeated handling. When  making  a  drawing  directly  on  tracing paper, you should place a smooth sheet of white paper  below  it  (detail  paper  works  well).  The whiteness of this sheet (called a platen sheet) gives better line visibility, and its hard surface makes it  possible  to  draw  good  pencil  lines  without grooving  the  tracing  paper. Do  not  usc  gritty  erasers  on  tracing  paper, especially when ink is to be applied. If erasures must  be  made,  use  a  green  or  red  ruby  eraser, which is only slightly abrasive. Abrasive erasers wear  away  the  surface.  Erase  carefully  so  you don’t  tear  the  drawing.  A  light  back-and-forth motion works best. If the surface of the drawing becomes scratched by erasing, it can be partially smoothed by burnishing the damaged area with a hard, smooth object or your thumbnail. Avoid using the electric eraser on tracing paper, as it will quickly  “burn”   a  hole  through  the  paper.  To clean  up  smudges  and  dust,  use  a  soft  art  gum eraser  or  sprinkle  pounce  on  the  drawing  and  rub lightly  with  your  hand  or  a  triangle. Water,  perspiration,  or  graphite  from  your pencil will ruin drawing paper. In order to keep moist hands or arms from marring the drawing, use a clean sheet of paper as a mask to protect the  drawing  surface  next  to  the  work  area. Between  drawing  sessions  you  should  protect unfinished  drawings  by  covering  them. Tracing paper must not be folded. The crease marks will damage the lines on the drawing and cause  blurred  prints  when  the  drawing  is reproduced. For that matter, no drawing should ever be folded. Drawings and tracings should be either stored flat or rolled and placed in cylindrical containers. Prints or drawings larger than 8 1/2 in.  by  11  in.  may  be  folded  so  that  they  can  be filed  in  standard  filing  cabinets. Besides  tracing  paper,  you  will  select  other types  of  paper  for  special  uses.  You  will  be  mainly concerned  with  the  gridded  papers  described  in chapter 2. The quality of the gridded paper that you will use is similar to that of tracing paper and should  be  used  in  the  same  manner. As you gain experience, you will learn which type  of  paper  to  use  for  each  drafting  assignment. Of  course,  you  will  be  limited  by  the  types  of paper available and the guidelines given to you by  your  drafting  supervisor. Drafting  Pencils For  the  average  drafting  assignment,  three  or four   pencils   are   usually   sufficient.   A   hard pencil, 4H or 5H, should be used to lay out the drawing  in  light  construction  and  projection  lines. A medium pencil, H or F, is then used to darken the required lines and to make arrowheads and lettering. The grade of drawing paper you use will also  determine  which  pencil  you  choose  for making a drawing. A soft, rough-textured paper usually requires a softer pencil for layout work, since a hard pencil would leave indentations in the  paper  and  thus  spoil  the  appearance  of  the drawing. One  way  to  find  out  if  you  are  using  the proper pencils on a drawing is to make a blueprint (reproduction) of the drawing. If the reproduced 3-2