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Lubricating oils

Oils whose primary use is for lubrication.

Machine oil

Machine oils are a class of thin light petroleum oils used for undemanding lubrication, such as small machinery, hand tools etc. They are also widely used to thinly coat steel tools before export, preventing rust.

Sewing machines and many other appliances use machine oil.

Some machine oils are edible, such as for use on food processing equipment, some are not.

Baby oil

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Baby oil is a highly refined petroleum oil, much like a food grade machine oil, with a little mild perfume added. Its a very convenient way to buy a machine oil for many DIYers. (The method of its extraction from babies remains a closely guarded secret.)

Engine oil

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Engine oils are excellent lubricants. They are highly stable petroleum derived oils, with additives to enhance their stability even further.

20/50 was once the most common engine oil grade, but 10/30 took over as the dominant grade a couple of decades ago. 10/30 is less viscous, and pumping it uses less energy. Engine oils are much more viscous than machine oils.

Used engine oil

Used engine oil is blackened by engine deposits and assorted burnt matter. It still lubricates, but there is potential for toxicity of a contaminant. Used oil is also believed to be carcinogenic to some degree, and garage staff are advised to use gloves when changing oil. These issues plus its gross dirtiness make it very unpopular for DIY use.

50/50 used engine oil plus paraffin or diesel has long been used to preserve exterior woodwork. Its cheap, but is dark in colour and the engine contaminants are an issue. New oil and paraffin/diesel at least avoids these issues.

Used or new engine oil can be used for steel hardening.

Castor oil

Castor oil was the original engine oil, and the source of the name Castrol. Its still available for historic vehicles designed to use it. Its a fixed grade of oil, unlike today's multigrades, so its viscosity varies more with temperature. Its much more prone to gumming than modern engine oils, and is not suitable for modern engines.

Gear oil

Gear oils are designed to survive higher shear forces than engine oils. Engine oil is not recommended for gearboxes (with the exception of the original Mini, which was designed to work with engine oil).

2 stroke oil

Another petroleum lubricating oil. Designed to produce minimum smoke and residue when burnt.

Silicone oil

Silicone oils and greases are much more expensive than other (carbon based) oils. They have fewer DIY uses, but are particularly effective for applications with plastics and rubbers which may be damaged by more traditional oils.

Silicone oils

  • insulate well electrically
  • conduct thermally.
  • are not flammable
  • don't degrade plastics and rubber compounds - and so are commonly used in some plumbing applications with plastic fittings and rubber O rings.
  • remain stable at high temperatures (over 200C)

Silicone oils are also found in anti-flatulence products, though this is possibly more 'don't do it yourself' than DIY.

DOT 5 Brake Fluid

Brake fluid is used in most automotive brake and clutch systems. While Dot 3, 4, and 5.1 are glycol ether based, DOT 5 is actually a silicone oil based fluid.

Chainsaw bar oil

A biodegradable "anti-fling" oil with added tackifiers. Its designed to cling to the cutting bar and chain and provide lubrication, reducing heat build up, and extending bar and chain life dramatically. Wrongly specified oils should not be used as substitutes, since they do not perform well and are harmful to the environment.

Airline oil

Drip-fed automatically into compressed air feeds for lubrication. Not recommended for lubricating air transport companies.

Fuel oils

Some fuel oils have DIY uses.

Gas Oil (35 second oil, red diesel)

Gas oil is found as the heating oil for some old installations.

  • Diesel fuel makes a cheap release agent when casting concrete in wooden forms.

Kerosene (Kerosene C2, 28 second oil, heating oil)

Kerosene is widely used for central heating. Market prices track crude oil prices, and it is worthwhile phoning around and pitting the suppliers against each other.

  • Kerosene is a less refined grade of paraffin, and therefore usable for many of the same purposes for DIY activities.

Paraffin (Kerosene C1, premium kerosene, premium burning oil /PBO)

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Best known as a fuel for heating & old blowlamps, paraffin has several other uses too:

  • mix with a heavier oil to make a penetrating oil
  • engine oil flushing additive
  • cleaner especially effective for all types of vehicle & road dirts, oils, tars and bitumen
  • insect repellent - sometimes a little was applied to window frames to discourage insects
  • softens scalpings to make it cold layable

Paraffin can be used neat for cleaning car parts, or it can be mixed with water & a detergent.

Historically, paraffin has been dyed with several different colours including blue, pink, yellow and green.

Lamp oil

Lamp oil is a deodorised dyed paraffin. It has the same uses but avoids creating the famous oil heater whiff.

Lighter fuel

Formulations vary and are proprietary to manufacturers.

  • Lighter fuel is a useful cleanser for metals, and evaporates quickly.

Decorating and Wood finishing oils

There are a range of oils popularly used for decorative finishing.

Linseed oil

  • A classic wood preservation and finishing oil
  • Thins oil based paints, but greatly extends drying time
  • Enables water based paints to adhere to a greater range of surfaces (mix in 1-2% linseed oil)
  • Makes a range of putties & mastics
  • Thins linseed putty
  • Makes tack rags
  • Used as an additive to many finishing oil mixtures for wood
  • The traditional oil used when building up (shellac based) French Polish
  • Distinctive strong pleasant smell

Raw & boiled Linseed

Raw linseed oil is just linseed oil. Boiled linseed oil is nowadays linseed oil with added chemical dryers. Boiled oil sets to a gum over a few days, raw either doesn't set or takes an extremely long time. Boiled should be used in all the above applications except French Polishing and tack rags.

Tung oil

Tung oil (aka China wood oil) is a natural oil used for wood finishing. Water, heat and alcohol resistant, it penetrates the wood and imparts a deep finish which enhances and brings out the natural grain of the wood. Applied in several coats, it can be built up into a relatively glossy finish. Once cured, it is a though finish offering good protection, which is also very easy to repair. Most commercial Tung oils are actually a blend of natural tung oil plus additives to speed drying, and eliminate the natural tendency of the oil to wrinkle when air dried.

Oils sold as "Pure tung oil" create a matt to satin finish that is also safe for use on food contact surfaces. Hence its a popular choice for salad bowls, chopping boards, and kitchen worktops.

Teak oil

Teak oil is a Wood finishing oil usually formulated from a mixture of Tung oil and Linseed oil. Its well suited to finishing hard and exotic woods, and naturally oily woods like Teak and Iroko. Usually supplied with added driers, and UV filters to make it suitable for both internal and external wood protection and finishing.

Danish oil

Also a blend of pure Tung Oil and natural oils. Traditionally used for many fine furniture finishes. Water, heat and alcohol resistant. Sometimes supplied blended with a varnish.

Hair oils

Hair conditioners are normally oils, and produce gloss and increased control. Oils are used in 2 ways: mixed in with shampoo for mild conditioning, or applied on their own after washing for stronger conditioning.

Commercial hair conditioners tend to use thick oils such as palm oil, castor oil, jojoba etc. Thin oils give less result. Lanolin grease produces stickiness.

Oil in shampoo

A little oil added to shampoo makes a conditioning shampoo. The percentage of oil is small enough not to produce any oily feeling or stickiness.

A spoonful of oil added to a litre of shampoo makes a very mild conditioner, or less than one drop per application. Oil content can be increased, but oil in shampoo gives an inevitably mild result.

The oil separates out on standing (commercial conditioners include an emulsifier to prevent this.) The mix needs shaking before use.

If a 2nd small container is used for the conditioning mix its easy to control how much conditioning you use each time, for better results than using the same conditioner strength regardless.

Oil after washing

A little oil is applied all over the hands, and rubbed into hair. The result is much glossier than oil in shampoo.

When using margarine, ensure its all spread over hands before applying, you don't want lumps!

Palm oil

Palm oil is a thick semi-solid natural oil, and a widely used hair conditioner in some countries. Its available from Asian grocery stores, and in low cost supermarket baking margarines.

Castor oil

Castor oil is another effective conditioning additive, but availability of the oil is poor, and allergic reaction to the castor bean is a known, albeit rare, phenomenon.

Coconut oil

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A good choice for sore skin that might rub & hair conditioning.

Vegetable oil

Vegetable cooking oils are thinner than the more usual conditioning oils, and less effective. Sometimes its adequate for mild conditioning.


Margerines are oils emulsified in water, and make a convenient way to apply hair oil. Palm oil margerine is sold as low cost baking marge.

Multi-purpose oils

A variety of commercial oil products are marketed as "multi-purpose oils". These products typically claim to be able to serve as lubricants, corrosion inhibitors, cleaners and penetrating oils. For most applications, a purpose-designed oil will be technically "better", but a multi-purpose oil is often ideal for a relatively undemanding application like a squeaking door hinge or inserting a screw. Multi-purpose oils can be had in small cans (with a spout) and aerosols (with a propellant).

A few branded products are well known in DIY and deserve their own mention.


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3-in-One is a brand of oil, marketed for lubrication, cleaning of metal and protection against rust. It is prone to becoming gummy, which limits its usefulness for lubrication. Nevertheless, it comes packed in a small can with a spout, so it comes in handy for all sorts of jobs.

At least one manufacturer of air conditioners recommends 3-in-One for use during making-up of flared pipe connections, because it does not contain unwanted additives.


WD40 is usable as a lubricant, penetrating oil, water displacer, rustproofer, cleaning solvent, and even as a cocaine use preventer according to the manufacturer. For each task there are better & cheaper options, but WD40 is one widely available product that can do all these when needed.

The manufacturer claims 2000 uses for WD40. While many of these are not uses we would rush to recommend, and many are simply duplication, there are some practical ones too. More uses & information.

There are complaints online of Appliances that have been ruined by the indiscriminate application of WD40. Opinions are mixed on whether there are common products and materials to which it should not be applied, such as some rubber & plastics.

From the manufacturer:

  • Rubber - OK with most rubbers on light surface spraying, some rubber will swell with prolonged exposure or immersion.
  • Plastic - Mostly OK, but polycarbonate and polystyrene may stress craze or crack in contact with WD40.

WD40 used to contain white spirit and a little mineral oil, replicating which is simple. Now it contains a different mix of solvent petroleum fractions.

WD stands for 'water displacer.' Water displacers are of limited use in DIY today, primarily used

Machine oil is the temporary coating of choice for preventing rust, and is widely used as a temporary rust prevention coating on imported steel tools.

WD40 also acts as a weak penetrating oil, though there are cheaper and better options out there, such as automatic transmission fluid.

WD40 is not a great lubricant as it contains mainly solvent, and tends to strip out existing lubricant, sometimes causing premature failure of motor bearings. And it can become gummy. But it's good enough for less demanding lubrication jobs.

WD40 can be used as a cleaner in some situations since it contains petroleum solvents. Paraffin & white spirit are much cheaper alternatives that don't leave an oily residue.

Test for plastic compatibility.

Other oils

High Viscosity Oils

Very thick treacle like oils are used on their own in dashpots, such as used to slow the opening of cassette deck doors.

They're also sometimes added to car engines to thicken the engine oil and reduce the blue smoke output of a worn engine. These oil thickeners are available from car accessory shops.

Penetrating oil

Penetrating oil is a mix of thin oil and a cutting agent such as paraffin which cuts the oil's viscosity.

Penetrating oils are able to penetrate tiny gaps and help unseize corroded fixings. These are much used in car repair.

If no penetrating oil is to hand, a mix of oil and a viscosity cutter (eg paraffin) works. Thin oil and paraffin are best.

Solvent oil

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Solvent oils are mainly used for cleaning off difficult deposits, like waxes and ballpoint pen ink. Orange oil is used in commercial cleaners, and olbas oil is often to hand.

Additives & alternatives

Engine oil & paraffin

A 50/50 mix is useful for

  • penetrating oil
  • corrosion inhibitor - but can become slightly sticky

The paraffin eventually evaporates. Diesel fuel can be used instead of paraffin, and evaporates more slowly.


Graphite is a solid lubricant. Graphite powder is sometimes added to oils to improve lubrication, and in some cases can even be used instead of oil. Its electrically conductive, which rules out some uses.

Graphite is used to lubricate locks, as unlike oil it doesn't attract muck.


PTFE 2516-2.jpg

PTFE aka Teflon is another dry solid lubricant.

PTFE produces toxic products if overheated, and should not be used in tasks where this is a possibility.

PTFE is a good electrical insulator.

Boron Nitride

A white powder used to lubricate locks. Less liable to stain than graphite.


Although not often used to reduce friction in DIY, it can be used as a temporary very low friction barrier between materials, such as when moving heavy items into place. Bin bags, rubble bags & dust sheets are suitable supplies.

Vegetable oil

Several plant derived oils are used for cooking. These lubricate, but over time they gum up badly. This greatly limits their use, but they're fine for jobs such as lubricating screws. Feeding the DIYer is the main use.

Vegetable oil is also occasionally used to clean oily, greasy or bituminous muck off hands. The veg oil is then washed off with soapy water. This sometimes works with clothes too.


Most margarines are plant oil (sometimes fish oil) based, with a large percentage of added water. These can sometimes be used as a last ditch lubricant, but they gum up eventually. The water content gradually dries out, but can cause corrosion until it does.

Petroleum Jelly (soft paraffin, Vaseline)

Protects bright metal parts from corrosion. Particularly useful to protect plated parts on vehicles during winter; washes off with warm soapy water.



Viscosity is measured in cs (centistokes), seconds, W or WT.

Centistokes are a standardised measure.

Seconds ratings are timings made in various ways, such as how long a given cup with hole takes to empty, or how long a ball takes to fall through the oil.

W and WT are not standardised measures, and the same viscosity oil could receive a different W rating by different manufacturers.

Multigrade Vs Monograde

Many automotive oils are "multigrade" formulations. These are oils that must meet two viscosity specifications; one for low temperature (i.e. Winter) and one for high temperature operation. For oils that meet the Society of Automotive Engineers (SAE) specifications, these are usually specified with two numbers like 10W-40. The first (or W) number giving the cold start (Winter) viscosity. Multigrade oils need to give adequate lubrication and protection for engines running at full temperature, but also not become so viscous at low temperatures that they prevent the engine turning over during starting in the winter.


The viscosity of oils varies widely with temperature. Higher temperatures produce a thinner oil. This is of course undesirable for some applications. Multigrade oils (ie 10/30 and 20/50) are designed to vary in viscosity less over temperature change.


Smoky engines

While there is more than one possible cause, vehicles with smoky engines are usually suffering from wear, which either allows tiny amounts of engine oil into the cylinder, or allows oil past the valve seals into the hot exhaust gases. Either way the oil burns, producing exhaust smoke with a blue tint. This gets past worn valve seals more often than piston rings.

Replacing 10/30 with 20/50 is often done to reduce smoking. Adding an oil thickener can reduce smoke output further. These are of course not proper cures and not manufacturer recommended, but have got a lot of cars through MOTs.


Many people bemoan the difficulty of finding a keyboard with a good key action. Almost any keyboard can be made to work well by oiling the stems of the keys. A screwdriver and knife are used to lift each key upwards, force is required and the key must remain level. A tiny fraction of a drop of machine oil is applied all round the key's stem, and the key pressed back in. After a few key presses the stem is then lined with a film of oil, and even unusably stiff keyboards are transformed into gooduns. Obviously don't use vegetable oil, it congeals over time.


Any type of oil or substitute can be used on screws, including margarine, a drop of oil from last night's curry, frying pan grease, candle wax, even chocolate. Plant derived oils gum up in time, sticking the screw firmly in place.

Hand Cleansing

Paraffin, dry washing powder on wetted hands and vegetable oil will tackle the grime encountered during many DIY tasks, and provide a budget alternative to proprietary hand cleansers.

Oil kit

Inevitably opinions vary on this, so this list is just intended as a quick starting point guide.

A good kit of oils for DIY may contain:

  • Machine oil (thin lubricant, rust prevention)
  • Engine oil (thick lubricant, car)
  • Paraffin (cleaning, insect repellent, additive)
  • Penetrating oil (frees corroded fixings)
  • Linseed oil (paints, putties, polishes etc)
  • Graphite or boron nitride (lubricating locks)


Oil lines should use only compression fittings.


New oil tanks must now be bunded to prevent contamination in case of leakage.

Storage of large amounts of flammable fuel oils is strictly regulated by law.


Cleanup methods include:

  • Applying an absorbent, such as wood powder or cellulose. This is standard in industry.
  • caustic soda
  • paraffin
  • hot pressure washing
  • burning the contaminated materials


Re-using the oil for something else is sometimes an option. Otherwise oils should be disposed of at the local tip, where it's recycled.

It's also possible to buy commercial workshop heaters that run on used engine oil. This is cheap to run, but there are concerns over contaminants.

Heating boilers have occasionally been modified to burn used engine oil. The relatively viscous oil must be preheated before a boiler not designed for such fuel can fire.

See Also