Painting And Decorating Paper 2 WASSCE (SC), 2018

Question 6

(a)      What is a primer?
(b)     State four primers for ferrous metals.
(c)     Outline the process of preparing a new ferrous metal surface for painting.

Observation

Candidates that attempted the question did very well. The candidates were expected to provide the following answers in order to score good marks:
           

  •      -            It is the first coat of paint applied to a new surface to prevent decay of 

      wood  and corrosion of metal.  

  •       The basis or foundation of the entire paint system upon which the

 stability of the success of the whole system depends.  

  •       A first coat on new metal or wood or on an old surface from which all

old paint film has been removed.

  •       The first coat of paint to be applied to any surface.                                                    

                                                                 
            (b)        -           Red lead primer;
-           calcium plumbate;
-           micaceous iron oxide;

  •       zinc chromate;
  •       zinc phosphate;
  •       zinc rich primers etc.

                 
(c)        -           Clean thoroughly to remove dirt’s;
-           sand or grit blast to loose rust and mill scale;
-           scrape/remove the loose rust and millscale;
-           wire brush the surface to remove corrosive substance;
-           clean the surface and allow solvent to dry off;

  •       apply primer after cleaning.