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're prone to mould if used in damp environments. Kitchen and bathroom formulations (and others) are available, or a mouldproofer can be added.

Prone to mild discolouring if used on radiators.

Covering ability varies widely: 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 many 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.

Dulux paints at DIY sheds and Dulux centres aren't the same. Quality and price are higher at the Dulux shops.

Household gloss

File:Gloss dulux 2532-2

• Oil based gloss for woodwork.
• Produces fumes during application and for a few days afterwards.
• Use over oil based undercoat
• Water based undercoats or primers can reduce paint life
• May also be used for walls & ceilings where easy cleaning and hard wearing are required, but ventilation during and after application is needed.
• 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, eg washing up liquid, binbags or baby oil.

Eggshell

• Oil based matt paint
• mainly used on walls
• harder wearing than emulsion
• ventilate the area after application

Masonry paint

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

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
• The term is also sometimes used to describe distemper or milk paints.
• Lasts well outdoors
• Exceptionally cheap at under £7 per 100kg

Preparation

1. Buy or prepare lime putty. Its prepared by adding water to builder's lime to make a putty consistency.
2. Dilute the putty 50/50 with water, and you have paint.

When extra sticking ability is needed, 1% of boiled linseed oil may be mixed in.

Adding skimmed milk to lime paint is occasionally done to improve toughness, but this is only good for indoor use.

Builder's lime gives a coarser paint than a mature putty. It suits exterior masonry.

Use

For exterior masonry, just paint it on. Add a second coat the next day, immediate overpainting just takes the first coat off. It looks excessively thin at first, but don't worry, it bodies up on drying, and bodies up again on curing, which takes a couple of days.

Lime paint isn't normally thickened, so it drips quickly from the brush. To minimise drips and maximise work rate, rotate the paint brush while you carry it from can to wall.

Cleanup is especially easy with lime paint, as even after drying it redissolves immediately in water. Outdoor work can typically be done with no covering of paths etc, and the path just rinsed off at the end of the day. If cured, the paint is readily removed with acid.

Lime is probably the quickest paint to use, as for most outdoor work there's no need to mask or cover anything, drops don't matter, and cleanup takes seconds with a hose. And single coat work is quite practical.

Check its not about to rain when painting, it can wash off. Once cured, lime paint is completely rainproof. Dry lime paint is also easily brushed off until it cures. This isn't particularly a problem in practice, as its trivially easy to patch it if ever needed.

Surfaces should be sound before painting, but on occasion the work involved isn't justified. In such situations lime paint soaks in well and provides some degree of bonding to a loose or powdery substrate. This works fairly well with crumbly old lime plaster, which coats of lime paint can bond back together.

Lime paint isn't for kids, it can do serious damage to eyes.

Colours

Lime is normally white.

• For a broken white colour, a very small amount of seived subsoil can be mixed in
• For pink, add iron oxide, sold as red cement pigment.
• For sky blue add laundry blue and use the paint immediately, else it bleaches in a few hours.
• Where a heavily weathered appearance is wanted quickly, add a little yogurt or rotted horse manure to the mix for quick biofilm formation.
• Coloured emulsion can be added in small amounts
• Adding kids waterpaints is yet to be tried. It probably would work fine with some colours, but not all.
• Lime is alkaline, and not all pigments are alkali stable.
• red, yellow, green, blue and black can be obtained using sheep raddle powder from a farmer's co-op or agrimerchant.

Thickness, coats and issues

Outdoor work is easily done with 2 coats, but its also possible to use 1 or 3.

Its possible to use a single thickish coat of slightly thicker mix for outdoor masonry where a fine finish isn't wanted. Wait until you're familiar with the paint's handling before doing this, as if the mix is too thick the paint will crack and craze. If that should happen, just put another coat on top, it fills the cracks fine and bonds properly.

An unusual way to apply lime is to use undiluted putty, wiping it on with a rubber grout spreader or similar. This fills the uneven masonry surface to a fair extent, producing a smoother finish, but not as smooth as rendering. It acts as filler and paint in one.

For a finer finish for indoor work, dilute the paint further and use several thinly applied coats. Use matured putty for the smoothest result.

There's plenty of misinformation about regarding surface compatibility with limewash and distempers, including from sources that should know better.

Distemper

• The forerunner of modern emulsion
• very 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 repeated 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, unlike emulsion.
• Distemper can be made at home, but so few people do it that its hard to know which recipes produce a cleanable paint. The basic formula is lime, fat, pigment, water and heat.

Potential Confusion

There are 2 different types of paint called distemper. There is soft distemper, which is discussed below inder the heading /Whitewash/ and oil bound distemper, discussed here, which is the more versatile paint. Oil bound distemper is a mainly 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. This probably accounts for the considerable amount of confused, conflicting and incorrect advice concerning distemper on the net.

Stove enamel

• A hard thick coating
• An exceptionally tough thick paint-like finish
• Used on cookers, a minority of high end cookware, and some other goods with long life expectancy
• Relatively expensive
• Not possible to paint such a finish on, the coated item is kilned after application

Powder coat

• Tough finish for metal goods
• Heated after application.
• Resin based

Whitewash

• Whiting (chalk powder) and water soluble glue.
• Very cheap
• Short lived
• Useful for temporary applications, such as greenhouse shading, where it gradually washes off in winter

Also known as soft distemper, it was widely used on ceilings until about 50 years ago. It is a matt paint and only one coat is needed. The natural colour of a greyish shade of white was normally used but occasionally it was tinted.

It can be (and should be) washed off before another coat is put on. During WW2 it was used on walls because it was the only paint readily available, but this gave it a bad name because it easily brushes off onto clothes.

Water based gloss

• A semi-gloss household paint used for interior 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 strong smell while drying
• Non-toxic
• Soaks into woodwork
• Boiled linseed oil is used to ensure drying
• Made with & without added driers (chemicals). Driers speed up drying time but shorten paint life.

Hammerite & Smoothrite

• For metal
• Pinholes badly

'Hammerite' paints were originally distinguished by (and named for) their finish.

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
• Generally solvent based

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 more 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
• For wood, GRP, steel and light alloy
• Correct primer also required
• Complete stripping normally required before application

Anti climb paint

This paint never sets, and is used to deter and mark climbing intruders. It can be bought ready made, or (so we're told) made by mixing equal amounts of household gloss and engine oil. Presumably it accumulates bugs over time.

Anti-climb should only be used out of reach of people on the ground, and a warning sign should be fitted.

Varnish

Varnishes can be regarded as clear paints. Several formulations exist with their own varying characteristics. Fancy writing an article on them?

Coal refurbishment paint

Paint for refurbishing coal? Almost - its for painting artifical coals used in gas & electric fires.

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 give more gloss than household gloss.

Preparation

General

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

• Clean the surface (see Discussion )
• 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's 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 wiping the plastic with solvent before painting. This has an etch like effect on the surface.

Unsound Surfaces

Surfaces not in good condition should be repaired before painting, but the demands of time and budget sometimes mean that crumbling plaster 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 years if not poked about.

Don't overdo the PVA. If a slick surface of PVA forms, paint doesn't stick to it, and painting 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 repeat coats may be needed.

Paints by purpose

Ceilings

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

Walls

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

Woodwork

• Gloss usually
• 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 makes it look very bad in time.

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, but is prone to fade and isn't 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 the better choice.
• Will also thin linseed paint, but not the best choice for this
• Good choice for brush cleaning with oil based paints
  • dirty white spirit can be settled and decanted for re-use

Linseed oil

• Thins linseed based paints.
• Can also thin other oil based paints, but will heavily extend drying times.
• Boiled linseed sets in days, raw takes very much longer and is not recommended for most paint uses.
• sometimes used to make lime paint stick to a wider range of surfaces

Cellulose thinners

• for volatile solvent based paints: cellulose, hammerite, smoothrite etc

Mixing

Mixing paints of the same type is straightforward. It works, and what you see is what you get.

• Be sure that every drop of the mix is well mixed
• Be sure you've mixed enough to do the whole job, trying to match it later can be a problem
• Keep some spare mix for maintenance
• Store your spare mix properly so it'll be usable
• Mixing can turn unpleasant colour leftovers plus white into nice pastel paints

Mixing paints with different base formulae isn't recommended, but isn't a no-go either.

• sometimes it works fine
• sometimes it doesn't work, they just won't mix
• sometimes it works but colour issues occur, eg the colour changes noticeably during drying.

Paint mixing can also be used to create special effects if you're willing to experiment. I once mixed 2 types of car paint in blue & green for use on some metal. It took persistence to mix it, but the 2 paints separated during drying, giving a fine hexagonal lattice of one colour filled in with dots of the other. The result was pretty and robust.

Paint Effects

See Paint Effects for a quick introduction. This covers

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

Paint Styles

Some colour schemes are presented in Colour Schemes.

Online Paint Scheme Tool

Paint schemes can be tried out at Online Paint Scheme Tool though its worth bearing in mind that on-screen colours 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.
• SPAB recommends using porous paints such as lime on the infill of Exposed timber frame buildings.
• Brickwork on old houses with no wall cavity should only be painted with porous paints.
• Shrunken paint patches: when putting water based paints over gloss, the old paint should be matted to enable new paint to stick. Otherwise the paint shrinks into little islands while wet (called "cissing"), and it takes several coats to get full coverage. A few options:
  • paint the gloss with a coat of matt oil paint.
  • lightly sand the old gloss first
  • rub in whiting with a damp cloth.
• For problems with masking tape see Tapes
• Lime paint behaves a bit differenly to other types, see Paint#Limewash for troubleshooting lime

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

For severe or very stubborn staining, use alternating coats of any 2 of emulsion, oil based matt paint and stain block. Sometimes several coats are needed.

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.

Oil paint

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. Its 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 looks like a poor bodge if they're not.

Emulsion

Simply paint over any marks on the wall. Use the minimum amount of paint possible, aim for a layer that covers imperfectly. The trick is to avoid patches that look new, so don't put too much on.

The result isn't as good as touched up oil paint, the patches are visible, but as long as only a thin paint layer is added they don't stand out, and they do make a wall look a lot better than unpatched, enabling it to go longer before repainting.

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

Steaming

A steamer which is normally used to strip wallpaper can be very effective in lifting layers of paint and should be safe to use on lead paint

Scraper

A scraper is the most popular method

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.

Methylene 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

• Linseed oil softens oil based paints

Ecover washing up liquid

• Contains low levels of 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 quicker than hand stripping, but has a habit of producing poor results and damage. Where the woodwork is of value, dip stripping is better avoided.

Electric Scraper

Electric scrapers have a vibrating blade, and are reasonably good at pulling layered 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 of detail.

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 progress is slow.

Paint stripping wheel

File:Paint removing wheel 1551-2.jpg

Abrasive impregnated nylon mesh disc, used with angle grinder. Less effective and less damaging than wire wheel.

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 unlikely to be encountered in house paints, but are readily found in artist's murals, frescoes etc.

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 pigmented 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 its 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

See Also

• Wiki Contents
• Wiki Subject Categories
• Traditional paints FAQ
• Mould Resistant Paint
• Paint Strippers - Wikipedia
• Paint Effects