Finding Solutions to common paint problems

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Air bubbles under the paint

This usually happens in gloss paint and is caused by applying paint in bright sunlight or on a hard shiny surface or on water-based undercoats. Use a chalky-type undercoat(e.g.Crown) on non-wood surfaces such as MDF.(Medium Density Fibreboard)

Bitumen and tar stains keep bleeding through paint finishes

Prime with an aluminium primer, then normal undercoat and topcoat.

Brushes; how to keep soft when not in use

Brushes that are being used in oil-based paints eg undercoat/gloss/varnish/stain can be kept soft by storing in water. Place brushes in a container and fill with water up to the tops of the bristles. Overfilling with water can result in water getting into the stock of the brushes and leaking out gradually while you are painting. Brushes can be kept soft for weeks at a time with this method (take care that the water does not evapourate in warm weather). Brushes used in emulsions and other water-based paints can be kept soft for several days by wrapping tightly in plastic bags ensuring that no air reaches the bristles.

Blistering paint

Caused by moisture pressure when exposed to the sun. Scrape off, sand down and repaint.

Color;not all the same shade

This is the result of not stirring the paint properly. Paint should be stirred thoroughly before use, especially strong and dark colors.

Cracking paint

Usually on old paint which hardens over time and is unable to expand and contract with changing weather conditions. With small cracks, sand down, fill , prime and repaint. With severe cracking strip back to bare wood, prime and repaint.

Flaking paint

This is the advanced stage of blistering and all paint should be stripped back to bare wood, primed and repainted.

Flashing(uneven sheen or matt areas in gloss coat)

Caused when paint is applied in misty or humid conditions or when condensation is forming. Allow to dry thoroughly and recoat under better conditions.

Flies; stuck on newly painted surfaces

Don't try and pick the flies out of the wet paint. Leave the paint to dry overnight and the flies can be wiped away with a damp cloth next day often without any trace.

Hairs/bristles; coming out of the brush

If you get a bristle in your paintwork don't try to pick it out with your fingers. Turn the brush and gently pick up the bristle with the very edge of the brush. Even very small bits of hair and bristle can be picked up this way.

Metalwork; paint flaking off

galvanized gate
This is a common complaint on galvanized metal which has been wrongly painted. Galvanized metal should be first primed with a zinc plombate primer.

Mildew

Remove with a weak bleach mixture. Mildew needs moisture to survive so identify and fix moisture problem before re-decorating.

Moulting brushes

Poor quality brushes often shed bristles. Also over-thinned alkyd paint causes moulting.

Nailhead stains showing through

Sand nailheads back to bare metal, touch up with a metal primer(e.g. red oxide), fill if necessary and re-decorate.

Paint is slow to dry

Emulsions and other water-based paints are normally quick to dry but can be dried quickly when required using a hot-air gun or a hair drier. Do not hold too close to the painted surface and keep the gun moving in a horizontal figure-8 motion. Oil-based paints can be helped to dry quicker by adding about half a teaspoonful of Terebine to each litre of paint. Do NOT try to dry oil-based paints using a hot-air gun.

Paint;runs

Runs are normally caused by applying paint too heavily. Always try to brush out the runs before the paint sets. Leave off with an upward motion of the brush.

Paint;chipping

Chipping off paint is caused by the top coat not having a sufficient key. Commonly the result of applying gloss finish directly on top of previously glossed surfaces. To prevent this you must first apply a suitable undercoat or sand down the surface with a fine sandpaper.

Peeling paint

Caused by moisture pressure when exposed to the sun. Scrape off, sand down and repaint. If stripped back to bare wood , prime and repaint.

Resin;bleeding through paint

Resin usually comes from knots in the wood. Prevent this by sealing the knots with a proprietary brand Knotting. French Polish or industrial shellac will also solve the problem.

Uneven or poor coverage

Caused by brushing out the paint too much. Apply another coat.

Water stains; on ceilings and walls

To stop stains coming through emulsion treat with a proprietary sealer such as Stainblock(Polycell) which comes in cans(brushable) or aerosol spray(ideal for small amounts and easy to apply). If you can't buy a proper sealer then coating the stain with gloss paint and allowing to dry will solve the problem.

Wood pigment stains

Some wood extracts, usually brown in colour, bleed through some paint finishes. Wash with soapy water, prime and recoat.

Wrinkling

Caused by applying second coat before the first one is dry or applying in strong, direct sunlight. Sand down until smooth and repaint.