Decorative Painting Tips: Surface Preparation
NEVER sand an MDF piece BEFORE basecoating. MDF is a type
of hardboard, which is made from wood fibres glued under heat
and pressure. It contains a substance called
urea formaldehyde, which may be released from the material
when you sand it - this
may cause irritation to the eyes and lungs.
If you see a dent in your wood piece
just when you are going to paint it
try "lifting" the
dent using a steam iron held close to (but not touching)
the dent. The steam will swell the cells in the wood
dent should disappear.
Wood is a porous thing and every application of something
wet will raise the grain of the wood. The grain WILL come up
- how much depends on the quality of the wood. Applying the
sealer coat first will minimise the amount of grain that is
raised in successive coats. In some woods, the grain will raise
when you apply the basecoat even after you have sealed it. Sanding
between each coat removes the raised grains and creates a smooth
surface for you to decorate.
To seal wood, apply a coat of All Purpose
Sealer or Clear Glazing Medium. If possible, leave it to cure
for about 48 hours. The longer, the better. Do not sand it before
it cures because the sandpaper will remove the sealer.