The biggest problem in painting is the person behind the roller or brush.
A Fold statement but true.

The majority of the problems of painting are human error. People think that by not sanding, not washing down, skipping coats, using the wrong primer or undercoat and many more little anomalies, they save time, get finished quicker and use less paints. By taking short cuts or using cheap paint when a better quality material is available, you are making more work for yourself in the long run.

Paints fail generally through lack of careful preparation of the surface.
Read and follow the directions shown on each can of paint. If in doubt, seek the advice of the professionals, either paint consultants in your local store or phone the paint manufacturers and ask their advice.
When I prime my exterior woodwork with primer, the acrylic paint I used over it, peeled off. Why?
Modern acrylic paints have many benefits when used correctly. In many cases they do not need sealers or undercoats. However, when being used on timber, it is most important to use only pink primer and to not red primer to prime the bare timber.
Red primers carry an excess of oil which do not allow the acrylic proper adhesion to the surface. These oils can also be drawn from the surface by the sun and cause blistering of the acrylic paints.
Check the label for directions or ask the advice of a paint consultant as to which is the correct primer for your job.

How can I paint over old varnish with an oil paint?
One of the biggest difficulties in painting over old varnish with oil paint is that there could be “bleeding” of the varnish through the new coat of paint. To avoid this happening, you must first wash down walls, lightly sand and then apply two coats of bleed sealer. The surface is then painted in the normal way.

Why does mildew re-appear on the walls in a bathroom after re-painting?
Mold or mildew will grow on any type of surface given the right conditions. This type of problem is most prevalent in rooms which lack adequate ventilation and suffer from excessive amounts of steam or warm moist air flowing through them.
Despite treatment with anti-mould solutions, mould and mildew can re-appear unless an effort is made to fix the problem at its source. The problem is usually completely cleared up by adding additional ventilation to the room;  an exhaust fan or extra ventilator will help, by creating an air flow through the room moist air does not have a chance to condense on walls and give the mould spores the opportunity to grow.

Paint blistering or bubbling after application?
This is a most common problem and is usually caused by some form of grease or moisture on the surface.
The way to avoid having paint blistering is to properly clean the surface before the application of any paint and to thoroughly sand the surface.

Why does exterior oil paint lose its gloss overnight?
In some cases, gloss paint can lose its gloss overnight. This is caused by frost or dew settling on the surface whilst the coating is not completely dry. The solution to this problem is to stop painting by mid afternoon when there is the possibility of frost or dew. Simply sand down and repaint the affected areas.

Why does paint bubble when using a roller?
Applying paint by roller can be fast, convenient and easy if you choose the right roller to do the job. Most roller related problems are caused by using the wrong roller with the wrong paint. Check the manufacturers specifications or seek help from your friendly paint advisor.

After painting my wrought iron with enamel, rust re-appeared. Why?
When painting a surface which contains any traces of rust, it is critical that all rust be completely removed or treated with a rust inhibitor. Even though, in some cases, anti-rust paints have been used, rust has continued to grow under the surface of the coating. The only adequate way is first total treatment of the rust and second, follow the manufacturers’ recommendations on what primer to use when re-painting.

Why did my gloss paint go flat when I thinned it?
Some people have experienced the problem of having a gloss enamel go flat on the interior of their house. Unlike the problem of having gloss paint go flat due to the exposure to dew or frost this problem is caused by the over thinning of the paint. Most paints come from the manufacturers ready to use. If thinning is required it should never be more than ten per cent maximum.