Paint

Paint can transform appearance, it can make a style, it can emphasise desired features and partially obscure others.

Types of Paint

Emulsion

Emulsion paints are water-soluble (until dried) and are the usual choice for covering walls and ceilings. They are available in matt and semi-matt (often known as 'silk') finishes.

• They are prone to mould if used in damp environments: "kitchen and bathroom" formulations (and others) are available for such locations.

• They are prone to mild discolouring if used on radiators.

• They vary widely in covering capability: the best (such as Dulux Trade) have a mayonnaise-like consistency and can cover even dark colours with 2 or 3 coats, normally requiring only one to give a good coverage on light surfaces. By contrast some 'shed' own-brands require almost infinite coats to cover even light surfaces. The thicker consistency paints are also less prone to splattering when applied with a roller.

• A wide range of colours is available off-the shelf and major brands offer ranges which can be mixed to almost any required colour.

Household gloss

• Oil based gloss for woodwork.
• Produces fumes during application and for a few days afterwards.
• May also be used for walls & ceilings where easy cleaning and hard wearing are required, but good ventilation during and after application must be provided.
• Curing takes longer than drying, so either avoid pressing painted surfaces together as soon as dry (eg door frames), or coat them with a lubricant to avoid sticking.

Eggshell

• Oil based matt paint
• harder wearing than emulsion

Masonry paint

• For exterior use only
• Not recommended for old non-cavity walls
• The term covers more than one formulation of paint

Limewash

• Lime putty & water
• Dead matt finish
• Limewash looks very thin on initial application, but bodies up both through drying and through carbonation over several days after application
• When extra stick is needed a tiny amount of boiled linseed oil may be mixed in. Don't add too much.
• The term is also sometimes used to describe distemper or milk paints.

Distemper

• The forerunner of modern emulsion
• Dead matt finish
• Distemper can be washed off with hot water and detergent
• Can be cleaned with cold water, but is not as robust as emulsion and will come off with persistent cleaning.
• Well suited to intricate mouldings, as its easy removal avoids paint build up over time obscuring detail.
• Mostly available in mid and light colours due to chalk content, but dark colours are possible.
• Sometimes chosen for its appearance, which is slightly different to emulsion
• Covers hairline cracks

Potential Confusion

• There are 2 different types of paint called distemper. There is soft distemper, which is not discussed here, and oil bound distemper, which is the more versatile paint. Oil bound distemper is a water based paint.
• Note that of oil bound distempers there is a fair variety of recipes, and not all perform identically. For example some less successful recipes wash off with detergent in cold water.
• The above probably account for the considerable amount of confused, conflicting and incorrect advice concerning distemper on the net.

Stove enamel

• A hard thick coating
• Possibly the toughest of all paint finishes
• Used on cookers, a minority of high end cookware, and some other goods with long life expectancy
• Relatively expensive
• Heated after application

Powder coat

• Tough finish for metal goods
• Heated after application.

Whitewash

• Whiting (chalk powder) and water soluble glue.
• Very cheap
• Short lived
• Useful for temporary applications, such as greenhouse shading

Water based gloss

• A semi-gloss household paint mainly used for woodwork
• Durability not comparable to oil based gloss paint
• Not very robust

Pliolite

• Matt
• Synthetic resin
• Pinholes heavily
• Longer lived than budget masonry paints
• Contains naphtha

Linseed oil paint

• Takes days to dry
• Nice smell while drying
• Non-toxic
• Soaks into woodwork
• Boiled linseed oil is used to ensure drying
• Made with & without driers (chemicals). Driers speed up drying time but shorten paint life.

Hammerite

• For metal
• Pinholes badly

'Hammerite' paints were originally distinguished by (and named for) their finish which resembles the appearance of some soft metals given a dimpled or crinkly hammer-beaten surface effect.

Hammerite now also produce paints with a smooth finish. Some varieties can be applied by sponge roller, which can give a consistent finish free of brush-strokes.

A particular characteristic of Hammerite paints is that they can be applied direct to metal, including rusted areas (but not to flaking rust) without a primer.

Ronson (and probably others) produce similar, competing paints.

Enamel

• Enamel is not one specific type of paint. It simply means a paint with a hard finish.
• The term enamel means the paint imitates stove enamel, which is an optimistic description for any paint
• Suited to rigid metalwork.
• Not suitable for wood

Car paints

Car paints are not flexible enough for use on wood. They are much tougher than a lot of household paints, and more expensive. Good for small items that will see a lot of use, eg painted handles.

Cellulose

Tough long lasting car paint.

Acrylic

A less expensive type of car paint used for respray work, still tough but can be prone to fade.

Japan black

• A high durability low cost black paint.
• Very popular during the early part of the 20th century.
• More info

Clay paints

• Limited range of dull earthy colours possible
• Minimal cost
• Easily made
• May be mixed with lime and/or red iron oxide to give a limited range of colours.

Vinyl Dye

• For painting plastics
• Penetrates the surface of the plastic for a more durable finish
• Solvent based
• Stinks

2 part polyurethane gloss

• Marine grade paint
• Super tough
• Currently around £40 per litre, plus cost of primer
• For wood, GRP, steel and light alloy
• Correct primer also required
• Complete stripping normally required before application

Finishes

• Gloss - shiny
• Silk -partial surface shine
• Matt - no surface shine, or almost none

Some matt paints are more matt than others, for example distemper & limewash are matter than matt emulsion.

Some gloss paints are glossier than others, car spray paints for example will give a much glossier result than household gloss.

Preparation

General

It is possible to paint directly onto almost any household surface, but a little preparation helps ensure consistently good results.

• Clean the surface
• Remove any flaking or bubbling paint

New plaster

New plaster is very absorbent, and needs extra water for the first coat of paint. There are 2 ways to do this.

Piss coat

• Paint with a 50/50 mix of emulsion and water.

Water coat

1. Paint the wall with a coat of water. There is no need for any particular care with this, so it can be done very fast.
2. Wait 5 minutes
3. Paint with normal strength emulsion.

• This method is quicker and no paint mixing is involved.
• Gives a full strength coat rather than a thin coat.
• If you paint before the water has soaked in the paint doesn't stick to the wall, if you make this mistake just give it a few more minutes.

Solvent weld plastic

Paint adhesion to solvent weldable plastic can be improved by wipping the plastic with solvent before painting. This has an etch like effect on the plastic.

Unsound Surfaces

Surfaces not in good condition should be repaired before painting, but the demands of time and budget sometimes mean that crumbling plaster and flaking paint needs to be painted. The simplest approach is to brush off any loose material using a household floor brush, then coat the surface with PVA diluted 1:4. Once dried this will normally give a surface that will last a while.

Don't overdo the PVA. If a slick surface of PVA forms, paint doesnt stick to it, and painting it successfully will be problematic.

If the existing surface is chalky, due to it being deteriorating lime paint or lime plaster, well diluted lime putty is a traditional alternative to PVA. This soaks in and rebonds the materials together, without the downsides of PVA, but more than one coat may be needed.

Paints by purpose

Ceilings

• Emulsion
• Distemper
• Limewash
• Gloss if a shiny easy clean finish is desired

Walls

• Emulsion
• Distemper
• Limewash for walls subject to light wear
• Gloss for a tough easy clean finish. Not as attractive as matt paints.

Woodwork

• Gloss
• Waterbased gloss
• Emulsion can be used but tends to not wear well
• Distemper to preserve fine detail where the woodwork is not subject to heavy wear
• Linseed oil paint
• Water based paints then varnish

Asbestos

• Emulsion
• Household gloss

Wood floors

• Paint not recommended, Normal wear will make it look very bad.

Concrete floors

• Concrete floor paints
• Epoxy paints

Exterior Masonry

• Masonry paints for cavity walls
• Limewash, especially for old non-cavity walls
• Pliolite

Iron & steel

• Car paints
• Hammerite, smoothrite & similar
• Enamels
• Household gloss can be used is prone to fade and isnt as tough

Plastics

• Vinyl dye

PVC

• Household gloss topcoat, no undercoat or primer
• This chemically bonds to the pvc, giving much longer paint life than on wood.
• Vinyl dye

Solvents

Water

• for all water based paints

Turps substitute

• Thins oil based paints
• Will also thin linseed paint, but not the best choice for this

White spirit

• Very similar to turps substitute, but affects the paint handling characteristics
• Turps substitute is preferred, but this also works.
• Good choice for brush cleaning with oil based paints
• Will also thin linseed paint, but not the best choice for this

Linseed oil

• Thins linseed based paints.
• Can also thin other oil based paints, but it will heavily extend drying times.
• Boiled linseed sets in days, raw takes very much longer and is not a good choice for most paint uses.

Cellulose thinners

• cellulose paints
• hammerite, smoothrite
• ...

Paint Effects

See Paint Effects for a quick easy introduction to paint effects aimed at people who have not used paint effects before, ie most DIYers.

This covers

• woodgraining
• ragrolling
• spotting
• marbling
• sprayed fades
• colourwash
• fibres
• camouflage

Paint Styles

Some colour schemes are presented in Colour Schemes. These include:

• 70s
• earthy
• medieval
• minimalist
• Victorian

Online Paint Scheme Tool

Paint schemes can be tried out at Online Paint Scheme Tool though its worth bearing in mind that the colour rendition will not generally be accurate.

Troubleshooting

• A cracked paint finish is generally due to use of a paint coat that was too thick.
• Failure to adhere may be due to surface contamination, eg with oil or grease
• Lime rendered exterior walls should be painted with porous paints, if paint is wanted.
• Brickwork on old houses with no wall cavity should be painted with porous paints if at all.
• When putting water based paints over gloss, paint the gloss first with a coat of matt oil based paint. Another option is to lightly sand the old gloss first, or to rub in whiting with a damp cloth. Otherwise the paint shrinks into little islands while wet (called "cissing"), and it takes several coats to get full coverage.
• For problems with masking tape see Tapes

Stains

Stain appearance is due to an underlying stain that is (fully or partly) soluble in the paint being used. 2 options:

1. Use a layer of paint based on a different solvent to block the stain. This normally means using an oil based undercoat on water based paints.
2. If this doesn't work try a stain block paint, which are sometimes more effective

Alternatives to paint

For Wood

• Varnish
• Wax
• Stain
• Liming
• Oiling
• No coating

For Walls

• Wallpaper
• Fabric drapes
• Panelling
• Wood cladding
• PVC cladding, not highly recommended

For Ceilings

• Wallpaper
• Fabric drapes

For Metal

• Polishing
• Plating
• Varnish/lacquer

For exterior walls

• Removing all paint with a stripper eg caustic
• Pebbledash
• Cladding
• Bare brick/stone/wood etc

Paint retouching

Paint retouching may be used between repairs to extend the life of existing paint finishes. It can also be used when there is not enough time to repaint.

Paint retouching is a fast minimal cost way to make a house look in much better decorative order. The ok can be made to look good, and even the tatty can be made to look ok.

Typically a room can be decorated this way using a teaspoonful of paint or less.

1. Clean the existing paintwork. This will brighten it up as well as clean it.
2. Obtain a teaspoonful or a miniature pot of matching paint. If you don't already have the paint you need, match to a cleaned fragment of paint, otherwise you won't get quite the right colour.
3. Colour matching is critical.
4. Use an artists brush with the matching paint to fill in any chips in the paint finish.

The 2 golden rules:

1. Paint tint must never be brighter than the existing paintwork, not by the tiniest bit. The match must be either exact or the new paint should be a fraction duller.
2. Never allow any paint whatever to overlap the edges of the chip hollows. Absolutely none. It is not necessary to fill the hollows fully, but any overlap at all ruins the effect.

This method works very well if the 2 golden rules are followed, but will look like a poor bodge if they're not.

Removal of Paint

Several removal methods are unsafe to use with historic paintwork. See #Toxic Paints section.

Blowlamp

• A cause of house fires and damage to woodwork
• Not advised with lead paints

Heatgun

• Not advised with lead paints

IR Heatgun

• Used around windows this avoids the risk of heat cracking the glass.
• More energy efficient, as the heat isnt being blown away
• Heat absorption dependant on paint colour

Sanding

• Not advised with lead paints

Stripping chemicals

Caustic soda

• Strips oil based paints
• Caustic soda with wallpaper paste added makes a gel which keeps the stripper in contact with the workpiece.
• Caustic destroys wallpaper paste unless its concentration is kept fairly low.
• Caustic & wallpaper paste makes a low cost stripper
• Avoid skin contact, caustic burns.
• No toxic fumes
• Splashes to the eye can cause major damage over time after the incident, so any such splash must be treated immediately and properly. Seek medical assistance.
• Neutralise caustic residue with a mild acid before repainting, eg citric acid or vinegar.

Methyene Chloride

Methylene chloride, also known as dichloromethane, will strip nearly any type of paint. It is fast acting and aggressive. It is a solvent with an array of known toxic effects, and good ventilation is important in use. Use it outdoors when possible.

Boiled linseed oil

• Softens oil based paints

Ecover washing up liquid

• Contains low levels of plant solvent oils
• Removes emulsion paints. Soak in a dilute solution for hours and the paint just wipes off.

Alcohol

• Softens emulsion
• Long soak needed

Acids

• Remove all lime based paints

Dip stripping

Dip stripping baths are routinely run until so weak that long immersion times are needed. Long immersion in caustic attacks the glues in the workpiece, often resulting in doors cracking apart and joints coming loose. The wood surface is also often left in poor condition after a dip strip. Dip stripping is quick but has a habit of producing poor results and damage. Where the woodwork is of value, dip stripping is best avoided.

Electric Scraper

Electric scrapers have a vibrating blade, and are reasonably good at pulling layers of paint off.

Wire wheel

High speed wire wheels (run on angle grinders) are extremely effective paint removers. They will also damage wood surface quite a bit unless used lightly, and even then are much too rough for goods with a fine finish. These are a fast way to remove paint from hard surfaces (eg tough concrete) or where surface finish is unimportant. There is no paint tough enough to resist them, but they don't get into depressions in a rough workpiece.

Low speed wheels (run in a drill) are reasonably effective, but a little force may need applying to get it to do the job, and they won't always remove everything.

Miniature wire wheels (run in a die grinder) are effective for very small areas.

Since all of these are rotary wheels, none will reach into corners properly. Cup wheels get closer than flat wheels, but are much less powerful at paint removal. Miniature die grinder wheels get closer than larger ones of course, but make much slower progress.

Toxic paints

White lead, grey lead and red lead are well known. Some lead paints are still in use. Historic arsenic green paints are also found occasionally. The others are less likely to be encountered in house paints.

A list of some of the more common toxic paint pigments:

Flake white

lead carbonate

Cremnitz white

lead carbonate

Grey lead

lead monoxide

Red lead

Paris green

sometimes contains copper acetoarsenite

Emerald green

sometimes contains copper acetoarsenite

chrome yellows

lead chromate

Less common:

Naples yellow

sometimes includes lead antimoniate

Cadmium yellows

Chrome green

lead chromate

Schweinfurt green

sometimes contains copper acetoarsenite

Paul Veronese green

sometimes contains copper acetoarsenite

Cadmium reds

Cadmium orange

Viridian

Chrome oxide

Manganese blue ;

Manganese violet

Cobalt violet

sometimes contains cobalt arsenate

Raw & burnt umber

Vermilion

mercuric sulfide

Removal of toxic paints

Lead paints are common, more so on older houses. They are still in use, although much less common than previously, and are liable to have been used on buildings as recent as the 1970s. They can cause serious health problems if handled wrongly.

Arsenic pigment paints are rare, but removal of those also poses a health risk. Arsenic paints in damp locations are also a risk, as a reaction may occur liberating an arsenic gaseous compound.

Generally it is safer to leave lead paint in place and overpaint it rather than remove it. This also gives the benefit of greater woodworm resistance and a more durable base coat.

Leaded paints should be removed when necessary in a manner which does not produce dust, and traps any dust that may occur. A gel paint stripper is ideal. Lead paints should not be removed with a blowtorch or hot air gun, or by sanding, which produce dust and disperse it into the air.

Handling of paints containing arsenic and other toxins is beyond the scope of this article. These are rare however.

For paint testing services, a good place to look is water testing companies, who test drinking water for a wide range of contaminants.

More information on toxic paints: http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/e90e9830b5080ecb/eadbad7afe47bc71#eadbad7afe47bc71

See Also

Wiki Contents

Wiki Subject Categories

Traditional paints FAQ

Mould Resistant Paint

Paint Strippers - Wikipedia

Paint Effects