Painting Tips and Techniques
PREPARATION: 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. It might sound harsh but experience shows that preparing the surface accordingly prior to painting is the first and most important step of the project.
TIP: Allow plenty of time for preparing the surface. Follow the specific product instructions and plan the steps to prepare the surface prior to painting accordingly. It will probably take longer than the actual painting.
- CLEAN THE AREA
Paint adheres better to a clean surface. Here’s 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.
- GET RID OF MILDEW
What is mildew?
It’s that spotty black, grey and brown mould that grows in warm, moist, low-light environments. Laundry rooms, bathrooms and shower rooms are mildew’s 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.
- 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 manufacturer’s instructions carefully.
- Exercise safety precautions – protective goggles & clothing, gloves, respirator.
- 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.
- PREPARE OTHER UNPAINTED SURFACES
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
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 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.
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.
- 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 of the methods described here to prepare the surface for a new coating.
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.
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.
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.
- 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.
- USE THE RIGHT EQUIPMENT
Ask any professional painter about the importance of the right equipment and they may tell you a few stories. It is extremely important to use the right equipments for the project. Taking shortcuts and using low quality equipment can cost you a lot more because it can affect the final result.
Before you start your paint job, please make sure you have a check list with the right equipment needed to get the job done well. There are a number of specific paint rollers, brushes and tools that are ideal for different painting application. Choosing the right equipment, product and technique will help to achieve your painting job faster, cheaper and better than alternative methods.