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HAZARDS FROM LEAD
HAZARDS FROM ASBESTOS
GET
RID OF MILDEW
CLEAN
THE AREA
PREPARE
GLOSSY SURFACES
PREPARE
BARE WOOD
PREPARE
OTHER UNPAINTED SURFACES
PREPARE
PREVIOUSLY PAINTED SURFACES
PREPARE
STAINED AND DISCOLOURED SURFACES
PREPARE
WALLPAPERED SURFACES
THE
FIRST STEP ... AND THE MOST IMPORTANT!
Unless you really love to paint and want to do it again soon
you absolutely must prepare the surface properly before you
paint.
TIP:
Allow plenty of time for preparing the surface. It will probably
take longer than the actual painting.
Hazards from Lead and Asbestos
Be sure to take the appropriate precautions when
preparing surfaces which may contain harmful materials such as lead
or asbestos. See our recommendations in the section below.
The paint on old houses or buildings may contain lead pigments.
White lead was used in house paints until the mid-1950s, and red
lead was commonly used in primers until the 1980s. Lead chromate
pigments were used in some red, yellow and orange colours, and
calcium plumbate pigment was used on galvanised iron and steel
structures up to the 1980s.
Lead test kits can be purchased from specialist paint stores.
If possible, the old lead-containing paint should be left
undisturbed and simply cleaned and repainted.
However, if you are removing lead paint inside:
Remove curtains and furniture and, if possible, remove or fully
cover carpet.
Close doors to other rooms.
Use drop sheets to catch debris.
Regularly clean up debris.
Wipe down all ledges, sills etc. with a damp cloth, and vacuum
floor to remove dust. Place in garbage bag for disposal.
Dealing with the Dangers of
Asbestos
Before 1983 most fibrous cement sheeting and roofing and some
textured coatings contained asbestos. Asbestos fibres present a
serious health hazard if they are disturbed and inhaled during
cleaning, repainting or removal.
Therefore cleaning or removal of mould and moss should be done
WITHOUT sanding, wire brushing or scraping so as not to create a
dust. Wash down with a low pressure garden hose.
If the fibrous cement sheet cannot be prepared or painted without
disturbing the surface, a sample should be tested for the presence
of asbestos. Contact your state EPA or Worksafe (National
Occupational Health & Safety Commission) in Australia, or the
Department of Labour, Occupational Safety and Health in New Zealand,
who will recommend a testing laboratory.
If it is proved that asbestos is present, and the surface will be
disturbed during the work, then a handling procedure recommended by
the EPA or Worksafe (OSH in NZ) must be followed. For large jobs, it
is recommended that a trained specialist contractor, approved by
Worksafe, be engaged to conduct the work.
GET
RID OF MILDEW
What
is mildew?
Its that spotty black, grey and brown mould that grows in warm,
moist, low-light environments. Laundry rooms, bathrooms and shower
rooms are mildews favorite places.
Can
you paint or stain over mildew?
No! The
paint or stain may cover it at first, but before long the mildew
will grow right through the new coating.
How
do you get rid of it?
-- Prepare a 3:1 mixture of water and household bleach (3 parts
water to 1 part bleach).
-- Sponge the mixture on the mildew, covering a 0.5m area around the mildew.
-- Allow it to remain on the surface for at least 20 minutes, and
reapply as it dries.
-- Rinse thoroughly with water.
-- Then wash the area with a mild detergent and rinse with water
again.
Always wear
goggles, rubber gloves and old clothes when working with bleach.
Never mix bleach with ammonia products. The combination can release
poisonous vapours.
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CLEAN
THE AREA
Paint adheres
better to a clean surface. Heres what you need to do:
On smooth surfaces: Mix a mild detergent with warm water and apply
with a rag or sponge. Rinse thoroughly with clean water to eliminate any detergent
residue. Allow the surface to dry completely.
Rough
surfaces
(masonry & tile): Apply detergent and warm water with a rag
or sponge, then clean with a bristle brush. If dirt and grease build-up
is substantial, use a stronger cleanser, like TSP or Sugar Soap. Rinse thoroughly
and allow the surface to dry completely.
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PREPARE
GLOSSY SURFACES
Glossy areas
should be dulled or paint/primer may not adhere well.
-- Sand with a fine grit paper such as #180 or #220.
-- Then remove any dust with a damp rag.
Chemical deglossers
are available, but require care and caution. Leaving a chemical
deglosser on the surface too long can soften and wrinkle the old
coating. If you use a chemical deglosser:
-- Make sure there is ample ventilation. Open windows and use fans.
-- Follow manufacturers instructions carefully.
-- Exercise safety precautions protective goggles & clothing,
gloves, respirator.
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PREPARE
BARE WOOD
First, check
for mildew. If you find that ugly, spotty black, grey and brown
mould, follow the directions in the "Get Rid of Mildew"
section. (Don't sand the surface before removing mildew, as
this will just spread the mould spores.)
Fill any holes or cracks with a
suitable wood filler, allow to dry.
Then, if the wood surface is rough, it should be sanded:
-- Use a medium
grit garnet paper (100 120 grit)
-- Always sand WITH the grain, never against it, diagonally, nor
across the grain.
-- To achieve smoothest surface, sand again with a fine grade
sandpaper.
-- Wipe away dust with a rag.
An alternative
method to achieve
the smoothest appearance, but only for timbers which do not
exhibit tannin-staining:
-- Apply a coat of water to the wood with a damp rag.
-- Allow it to dry 30 minutes to raise the grain of the wood.
-- Sand with fine garnet paper to remove the raised grain.
Apply a heavy
coat of stain-blocking acrylic primer and allow to dry overnight. A second
coat can be applied if staining is evident. Oil-based or alcohol-based
stain-blocking primers are best for high-staining, tannin-rich woods like
merbau, kwila, cedar. (Proper ventilation and the use of a respirator are
required with oil or alcohol-based primers.)
After applying
stain-blocking primer and allowing it to dry, light sanding may
be required before a finish coat is applied.
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PREPARE
OTHER UNPAINTED SURFACES
New
Wallboard
Before painting
materials like new plasterboard or gypsum board be sure all joints
and patches are sanded smooth, dusted with rags or vacuumed. Next
apply an acrylic sealer/undercoat. Pay attention to the manufacturer's
instructions and spread rates.
New
Plaster
Allow plaster
to dry thoroughly. With a simple patch job, this will take one to
two days, for larger areas like walls and ceilings it can require
a week or more depending on the weather and interior humidity conditions.
Thick plaster applied in extremely humid conditions it can take
a month to dry adequately. Once dry, all rough areas must be sanded
smooth with medium grit paper followed by a second treatment with
fine grit paper. Clean surface of all dust with dry rags or vacuum
and then apply an oil based undercoat or a stain-blocking interior acrylic primer recommended
for plaster surfaces. Be sure to wear a mask and protective eyewear
when sanding.
Tile
Treat any suspected
mildew and inspect grout joints and repair them as necessary. Next
wash the entire surface with a detergent and an abrasive non-metallic
pad. Rinse and dry thoroughly. As an option to guarantee maximum
adhesion, sand the tile surface with a fine (#220) aluminium oxide
sand paper. Clean area off with a damp rag. Specialty, tile paint
systems are available from some paint brands which include a high-adhesion
interior acrylic bonding primer. This type of primer requires the
use of a respirator and ample ventilation. Allow it to dry thoroughly
before applying a finish coat.
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PREPARE
PREVIOUSLY PAINTED SURFACES
Inspect the
surface for cracking, peeling, flaking, loose paint. Depending on
the severity of the damage you may choose to employ one or more
the methods described here to prepare the surface for a new coating.
Scraping
This is
a traditional effective approach for most flat surfaces from plaster
and wallboard to wood and ferrous metal. Use shaped scrapers like
triangle or oval shapes to get into corners and on rounded profiles.
Take care not to gouge, score or otherwise harm the surface. Feather
sand all rough edges with a medium, then fine grit garnet sand paper.
Wire
or Bristle Brushing
Use a stiff wire
brush, being careful not to damage the substrate. Once all loose
paint has been removed sand the surface with a medium then fine
grit garnet sand paper.
A stiff bristle brush is often a better choice than a wire brush, as it will not leave any metal swarf in the paint film which may cause rust spots if the surface becomes moist.
Filling
Any holes or cracks in the surface should be filled before the surface is sanded. There are many types of filler available. Choose one that is specific for the type of surface (eg plaster, wallboard, timber etc), and for the size of crack or hole that is to be filled.
Sanding
If the surface
is just flaking slightly you can simply sand the area with progressively
finer grit garnet papers starting with coarse, then medium, then
fine.
Chemical
Paint Removers
Choose a paint
remover that is recommended for the coating and substrate you're
preparing. Apply a heavy coat of the remover with an old or a low-end
natural bristle paint brush since the remover will likely ruin the
brush. Give the product plenty of time to work as recommended by
the manufacturer, usually 15 to 20 minutes or longer depending on
the thickness of the old paint. Carefully remove the softened paint
using a putty knife or wooden blade and scrape the material into
doubled paper grocery bags inside a cardboard carton. Reapply more
stripper if needed and then clean the surface with wadded up paper
toweling, newspaper or a commercial pad designed for this purpose.
Before using these products, clear the area of children and pets.
Cover floors and steps and remove plants, rugs and furniture. Dispose
of all refuse after the job carefully following manufacturer instructions.
Wear goggles or face mask for eye protection; use chemical resistant
gloves, long sleeve shirt and pants to protect the skin; and protect
breathing with a respirator designed for use with chemical solvents.
There are low odour alternatives to the strong solvent removers,
but they may take several hours to accomplish the same job. Once
the remover has done it's work, sand the surface thoroughly with
fine garnet paper and dust before applying primer, stain or varnish.
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PREPARE
STAINED AND DISCOLOURED SURFACES
Water
Stains
First,
make sure that the source of the stain has been discovered and eliminated.
Then:
-- Clean as much of the stain as possible with a mild detergent
and water, then rinse with plain water.
-- Allow the surface to dry
-- Apply a stain-blocking primer. It can be oil-based, alcohol-based
or acrylic. Oil-based and alcohol-based are better for tough stains,
but require good ventilation and an appropriate respirator.
-- If you can still see the stain, apply a second coat of primer.
-- Allow the primer to dry completely, then apply the finish coat.
Tobacco,
Fire Damage, Soot, Grease
-- Clean as much
of the stain as possible with a mild detergent and water, then rinse
with plain water.
-- Allow the surface to dry
-- Apply a stain-blocking primer. It can be oil-based, alcohol-based
or acrylic. Oil-based and alcohol-based are better for tough stains,
but require good ventilation and an appropriate respirator. If there
is fire damage, an oil-based primer will also minimise odour.
-- If you can still see the stain, apply a second coat of primer.
-- Allow the primer to dry completely, then apply the finish coat.
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PREPARE
WALLPAPERED SURFACES
If at all possible,
remove wallpaper and adhesives before painting! If you must paint
over wallpaper, you may have problems with curling, staining and
uneven textures.
How
To Remove Wallpaper:
Remove old wallpaper by peeling, soaking and scraping, or steaming
and scraping. Scrub off any glue or sizing and rinse thoroughly.
Gouges and scratches should be patched with plaster or spackling
compound, then sanded and dusted with a damp rag. Before painting,
apply interior oil-based or acrylic stain-blocking primer.
If
You Must Paint Over Wallpaper:
First check for loose areas of paper and open seams. Re-glue these
problem areas. Next, follow these steps on a small out-of-the-way
area of the room to see if the paint will look okay. Make sure to
include a seam in the test area.
-- Apply an
oil-based, stain-blocking primer. Make sure there is ample ventilation
and use a respirator.
-- Allow the primer to dry overnight.
-- If there is discolouration when dry, apply a second coat of primer.
-- Apply a finish coat to the test area and allow it to dry. (A
flat finish paint will minimise the texture of the underlying paper.)
-- If necessary, apply a second coat and allow it to dry.
-- Evaluate the test area to see if you will proceed with the entire
room.
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