DIY - Panduan Mengecat Rumah

Paint application

Visible under colour

When painting with gloss you will need an undercoat to hide strong colours underneath. Here are some things you can do to make sure you don’t see the under colour peeking through.

To avoid visible under colour:

• Use good quality brushes and rollers
• Use a colour darker than the wall you are painting onto
• Apply undercoat
• Apply paint evenly

TIP – don’t worry if you can still see the original colour after the first coat, the second coat will cover, this is normal.

TIP – yellows, reds, oranges are what we call “low hiding” because of the pigment they sometimes need a couple of coats to cover.

Uneven roller marks

A high quality paint and roller should provide a smooth paint finish. If your roller edge leaves marks you can cut the edges to round their shape.

Make sure you always prepare the surface of the wall so it is clean, even and dry before you start.

How to use a roller:

• Wash before use
• Remove any excess water
• Load evenly with paint
• Apply even pressure (not too hard)
• Spread paint evenly with vertical strokes
• Always try and work as quickly as possible across the wall in even sections, paint from top to bottom. Try and maintain a “wet edge and don’t worry if the paint you applied at the beginning looks a different colour, it is drying down.

Uneven paint finish

If you are painting on a porous surface, using a primer is very important. If you don’t use a primer, the paint may be absorbed into the wall unevenly, leaving a poor finish. If you are finding that the surface looks uneven, check that there was no contamination on the wall before you started. Grease from cooking, bleach residue from cleaning, can both have an effect on the way your paint looks.

Getting a good paint finish:

• Use a primer on porous walls
• Stir the paint before you use it
• Avoid overlapping your paint strokes
• Make sure the surface is clean!

Spattering

When you are using a roller to put paint on your interior walls, paint can spray out over your hands and clothes.

To avoid spattering:

• Buy a good quality roller
• Use slow, smooth strokes
• Don’t overload the roller with paint
• Don’t use too much pressur

Lapping on interior surfaces

Lapping on interior surfaces can mean darker or glossier areas showing on your painted surface. Or even visible brush or roller marks.

How to avoid lapping:

• Maintain a wet edge during painting
• Prime porous surfaces
• Try not to let paint dry too quickly
• Apply paint evenly
• Work the paint across the wall in the same direction all the time, e.g. from right to left try not to work back over yourself
• Don’t thin the product too much

Foaming and cratering

Formation of bubbles and foaming, resulting in small, round concave depressions or craters. These occur when bubbles break during application and drying.

How to avoid foaming and cratering:

• Don’t stir the paint too much
• Use appropriate brushes and rollers for your job
• Don’t over dilute the paint

Paint runs

When paint runs it leaves an uneven surface, can look terrible and be difficult to remove if allowed to dry.

How to avoid paint runs:

• Don’t overload brushes and rollers with paint
• Don’t paint in humid or cool conditions
• Don’t over dilute paint
• Remove runs when paint is still wet using a damp sponge

Non-uniform colour or “picture framing”

A non-uniform colour may appear when paint is applied on walls with a roller, but brushed in around the edges. The brushed areas usually appear darker and look like a picture frame.

How to avoid non-uniform colour:

• Make an edge with a brush first
• Use a roller over the top of the brushed area as close to the edge as possible

Wrinkling on interior surfaces

Wrinkled paint is a rough, crinkled paint surface, this happens more outside and on interior timber surfaces.

How to avoid wrinkled paint:

• Clean the wall properly
• Don’t apply paint too thickly
• Don’t paint during extremes of temperature – too hot or too cold or damp weather, causing the paint film to dry faster on the surface than at the base
• Don’t apply a topcoat over an insufficiently cured/dry undercoat

Crackling, flaking, chipping

The splitting of dry paint film through at least one coat thickness. Initially the problem appears as hairline cracks; and later on paint chips flake off, leading to complete failure of the paint.

How to avoid cracking, flaking and chipping:

• Don’t over dilute the paint or spread it too thin
• Prepare the surface well
• Use a primer when necessary (previously unpainted, porous surfaces contaminated surfaces, etc
• Don’t paint apply too many coats

Blistering

Blistering is the formation of bubbles resulting from local loss of adhesion and the lifting of the paint film from the underlying surface.

How to avoid blistering:

• Don’t apply paint on damp or wet surfaces
• Clean the surface of dust or dirt

Paint rejection

Paint rejection may occur as soon as the paint is applied, producing stripes and round concave depressions or craters on the paint film. There is only one cause and that is contamination of the surface you are painting.

How to avoid paint rejection:

• Make sure the surface is free of grease and is thoroughly clean

Sumber: http://www.liquidimagination.eu/paint-expert/interior-paint-tips/paint-application/