Undercoating

A good undercoat is,more than anything else,the basis of a good paint job. Any’pimples’,rough patches or unevennessof colour in the undercoat will show through the gloss paint,particularly if this is one of the lighter shades.So the objective in undercoating is a velvet-smooth surface and an absolute evenness of colour.

    White and the reds ,particularly are likely to show up all imperfections.For white ,two coats of undercoat are best.For red,the evenness of colour will be improved if a tube of tint colour the same shade as that of the topcoat is mixed in well with the undercoat.

  With the paint in your paint kettle at the right depth,dip in the brush and wipe off any surplus on the inside of the kettle.Beginners often make the mistake of dabbing on too much paint too lightly;this causes the ugly ,sagging effect known as ‘curtaining’.The correct way is to make the paint spread as far as you possible can while still looking even in colour.

  Paint first with the grain of the wood,holding the brush quite firmly and whithout lifting it except where it naturally rises from the surface at the end of a stroke.Without reloading the brush,and pressing much more lightly,work backwards and forwards across the grain.This avoids a striped effect by eliminating the first brush marks.Finally’lay back’.Holding the brush almost flat with the work,brush so lightly that you can hardly feel the bristles touching the painted area,and in one direction only –with the grain,and working from the newest edge of the paint(the ‘wet edge’)back towards the previously painted area.

  When you load your brush for the second time,start applying the paint,not on top of the existing wet edge,but one brushload away from it,and work back towards the already-painted bit.This avoids a build-up of paint in one place-the prime cause of curtaining.The strokes,on a wide flat surface,should be about 305-457mm(12-18in).

  Edges are tricky;they catch the tip of the brush and release a globule of paint around the corner.Avoid this by stroking towards edges,where possible,rather than away from them.If you do cause a run in this way,wipe the paint of your brush and’spear ‘ off the run by pushing(instead of drawing)the brush.The same trick is used to pick up any stray bristles that appear.

     Allow 24 hours for the undercoat to dry.Sand off any pimples,brushmarks or other irregularities with grade 1 glasspaper ,and remove the dust with thinners –dampened rag.If the undercoat is uneven in colour-remember,the gloss coat will probably not correct this-repeat the whole procedure.It is well worth the trouble to get a first-class job.Once the undercoating has been completed ,clean brushes and kettle thoroughly once more.

 

 

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London Painters and Decorators