Best Penetrating Oils for Rusted Bolts.

There are many penetrating oils for rusted bolts out there, but the question is, which one is the best?
Penetrating oil, which is also referred to as penetrating liquid, is a low-viscosity, petroleum-based lubricant. This means that the flow is effortless when applied to the affected area of a rusted opponent. In this case, we’re looking at oils used for rusted bolts. The oils listed below got their name from their capacity to penetrate even small spaces in the middle of two parts between threads. They usually displace other materials and in turn, leave a thin coat of oil in the surface of the object’s pores. These oils tend to vaporise after short periods of time which means it is advised to not be used for general lubricating purposes, as there would be very little lubricant remaining.

Some of the best penetrating oils are listed below:
Kano Kroil Penetrating Oil
Blaster Penetrating Catalyst
WD40 Penetrating Oil
Gibbs Brand Lubricant
3-in-One Multi-Purpose Oil
Kano Aerokroil Penetrating Oil
Liquid Wrench Penetrating Oil
Royal Purple Maxfilm Synthetic Penetrating Oil

Penetrating oils are generally made up of a mixture of zine dialkyl thiosphate, methyl silicone, polymethacryalate, tert-dibuty-p-cresol, alkyl succinic acid, lowel alkyl benzenes and lower alkanols in a stock of kerosone bright lube oil. The alkanols elements are usually included as lower alcohol variations, such as propranolol or methanol. Economy and tax purposes call for a mixture of methanol and isopropanolol in a ratio of 1 to 5. The bright oil base is developed normally from a mixture of natural paraffin oils that are typically pre-treated for low and high viscosity lubricants. When used in penetrating oils, antioxidants and reducing agents are regularly added to oils for motors, but may vary in quantity.

What are the types of penetrating oils?

The types of penetrating oils below have solid lubricant particles that exist in a synthetic or natural oil base and are generally fire resistant. The particle of the oil can be of any variety of solid lubricant and the best examples include polytetrafluorothylene, graphite and boron nitride.

Straight Oils
Straight penetrating oils are the ones often used for mechanical applications and are non-emulsity oils made from base mineral lubricant with esters, fats or extreme pressure additives including phosphorous, sulfur and chlorine.

Synthetic or Semi-Synthetic Fluids
Semi-synthetic and synthetic penetrating oils and penetrants are composed of synthetic compounds, such as: blends of synthetic fluids and water; chlorofluorocarbons, di-esters, poly-glycol and silicone.

Emulsion and Water-Soluble Fluids
Emulsion and water-soluble liquids have a very low concentration or high dilution and consist of high-water content fluids. These penetrating oils and penetrants are usually in a diluted version with concentration percentage of up to 10%.

What is penetrating oil used for?

Standard uses
The regular standard uses of penetrating oils include energy, automative and manufacturing firms. There are usually three general applications concerning standard uses:
As an anti-corrosive coating or as a water repellent
Loosening trends on axles, seized bolts and other fasteners
Oiling sensitive or fast-moving machine parts.

Penetrating oils with a low viscosity allow them to lubricate parts without much resistance at all. It is usually easier to apply as well as reapply, especially with a penetrating oil from an aerosol spray to reach to the hard to reach areas. This means that low viscosity oil seeps deep into the smallest of places when it is applied to stuck threads. It helps loosen encrusted deposit and free any pieces. Any tight parts will easily loosen with a good penetrant, especially those who make noise. Good reviewed penetrating oils for rusted bolts tend to be effective at protecting aluminium and iron from continuing rust, this is because the oil has a trend of expanding across the applied surfaces in a uniform coat and is capable of repelling any water molecules.

Non-standard uses
Penetrating oils are made up of hydrocarbons with up to 20% in liquefied carbon dioxide and an exception of 10% to 15% in inert materials. One of the outstanding nonpolar solvents, which is normally liquid under normal conditions is hexane.
A polar solvent like water, is typically effective at breaking up and dissolving specific substances, including metal ions, sugars and salts. Although, water is useless for dissolving non-polar solvents such as plastics, fats or oils. For that reason, penetrating oils can be used to get rid of:
Spray paint
Acrylic paint
Dripped varnish
Permanent marker, stickers, chewing gum and among others that cannot simply be broken down by water.

  1. Kano Kroil Penetrating Oil
    It is reviewed that Kano Kroil penetrating oil is the best for rusted bolts. It penetrates and loosens frozen metal parts in just a few simple minutes.
    Kroil penetrates to 1 millionth inch spaces, dissolving and preventing rust without attacking the metal. The oil displaces water, dissolved gum, dried grease and provides lubrication.

    Kroil has a unique chemical structure that was engineered chemically in a labatory. This defines the interdisciplinary electrical, physical, chemical mechanical properties that work well with joint metal parts.
    The scientific principle behind Kroil’s working is that it reduces surface tension and creeps in to small areas. The oil has a unique molecular architecture creating an affinity to the metal. If you are trying to save money, because Kano Kroil is quite expensive, it is advised to not pour so much of it on the object and avoid spillages.

What are the uses of Kano Kroil Penetrating Oil?
You can use the oil on mowers, tractors and autos. It can easily loosen a bolt or a stripped screw stuck together with rust. It also works on brass and aluminium threads and can resolve frozen fittings of objects such as cameras.

How is Kano Kroil Penetrating Oil Used?
It is a very simple task using Kano Kroil. All you will need is a cotton ball, or something similar, put the ball on the mouth of the bottle and tip it to fill with Kroil – remember to try not to spill any! Place the ball in any place you want rusting to be prevented. Two drops of the oil should be sufficient enough to deal with metal rust. If you are looking for a confined space to be unrusted, you need a narrow mouthed bottle, specifically with droppers or a spout and pour the oil into the holes. If you find an object that is loaded with corrosion or frozen and seized, Kano Kroil will deal with it.
Kano Kroil is safe to use on metal, rubber, plastic and any painted surface. It was a pout for convenience and precision with application, there is no expiration date, ir can be used on a wide range of hardware, tools and equipment and it does not harden, gum or expire.

2. Blaster 16-PB Penetrating Catalyst
The PB Blaster busts loose, frozen or rusted parts caused by corrosion and rust. It contains a no evaporating lubricant, which saves time and also protects against further corrosion and rust in the future. The spray works on rusted nuts and bolts by just spraying and letting it sit for a while. The penetrant creeps up, spreads and surrounds any hard-to-reach areas, allowing parts to escape surface tension of corrosion and rust. Blaster 16-PB offers a hardworking, top-quality formula which leaves behind lubricating film to prevent any further rusting. Due to the spray being so fine and like a mist, it manages to get into the smallest of openings in between metal parts. It will then loosen the metal connection that appears rusted over time.
Although, this product lets off a lot of fumes, so if you consider using it, ensure it is in an open space or the air circulation is affective.

How should Blaster 16-PB Penetrating Catalyst be used?
After spraying PB Blaster on fused parts, give it several hours or even the entire night to sit for the penetrating oil to seep in. You can use your wrenches afterwards to loosen the parts a little bit. If they will not budge, try a second heavy dose of the oil and let it sit for a while. Using heat on the stubborn parts can also make them loosen while using the oil.

What are the uses of Blaster 16 PB-Penetrating Oil?

PB Blaster can be used on automative, plumbing, industrial and on other equipment. You may need to apply it 1-3 times depending on stiffness of the stripped bolt or rusted nut. The penetrating catalyst is useful, especially when you have rusted or corroded nuts or bolts that will not budge.
It is said that Blaster 16-PB Penetrating Catalyst is the best seller since 1957 and outperforms leading competitors with its high-performance formula. It is also effective, saves time and has multiple uses.

3. WD-40 Multi-Use Product with Smart Straw
The WD-40 is a multi-use product that penetrates stuck places, protects metal from corrosion and rust, displaces moisture and lubricates anything. It is water-based aerosol with a unique bio-solvent proven to be more powerful and easy to use degreaser in the market. It breaks quickly through tough grime and grease and it is the best when it comes to cleaning tools, shop floors, greasy automative parts, commercial appliances and many more. The added corrosion inhibitors present in the product help in protecting against flash rust.
While the WD stand for water displacement, the product is a rare special blend of lubricants. The formulation of the product contains anti-corrosion agents and components for penetration, soil removal and water displacement.

What are the functions of WD-40 multi use product with smart straw?
Protects: The product has corrosion-resistant ingredients that shield against corrosive elements and moisture. You can use it on any metal surfaces for long lasting protection.
Frees sticky mechanism: Use the product to loosen rust-to-metal bonds and free frozen, rusted or stuck metal parts.
Removes: It can get under grime, grease and gunk. It dissolves adhesives allowing quick and easy removal of tape, labels, excess bonding material and stickers.
Lubricates: The products lubricating components are widely dispersed, holding to all the moving parts.
Drives out moisture: It displaces moisture by drying out electrical systems and eliminates moisture-induces short circuits.

What surfaces are safe for use with WD-40 multi use product?
The product is safe on almost anything. You can use it on rubber, most plastics, wood or metal. However, avoid using on clear polystyrene plastic and polycarbonate. You can use it on your bike for preventing rust and mud from sticking or sports equipment. The product should be handled with care because it may soften car polishes and other products on contact. This invasive nature means that you should take extra care around unsealed bearings and rubberised synthetics.
WD-40 is a multi-use lubricant smart straw with a permanently attached straw so it sprays two ways. It has one formula but five functions. There are thousands of uses of WD-40, so it is ready for everything and it is safe for almost anything too!

4. Gibbs Brand Lubricant
Gibbs brand is a lubricant with many uses both for domestic and industrial purposes. It is a revolutionary product that works in any temperature not only to eliminate corrosion, but also to clean, to waterproof and lubricate mechanical hardware.
It is safe to use on rubber, wood, metal and plastic.
The product is pricey and due to the high pressure, it makes the product run which makes a mess in itself.

What are the major uses of Gibbs Brand Lubricant?

Rust removal
Surface conditioner
Penetrating oil

What is the best way to apply Gibbs Brand Lubricant?
The product is easy to use.If you start with a clean surface and spray a small amount of it in a few streak movements across the ear you are working on, then use a clean towel to gently swipe the product across the entire surface. Use a clean towel again to wipe of any excess and unwanted liquid.

  1. 3-in-ONE multi-purpose oil
    As the name implies, 3-in-one multi-purpose oil can be used for various applications. This includes: loosening frozen parts, reducing friction and getting rid of rusty joints. You can also use it to grease, remove gum and to silent components that make squeaky noises. The product has the capacity of loosening parts that have been stuck together for a long time. It seeps into crevices and frees stuck parts in minutes. For cleaning functions, this oil is very useful as it removes grime and dirt effortlessly.
    The oil works as a lubricant and does not have any foul smell. It can be used at home on hinges, door locks, sliding doors, fans, sewing machines, window tracks, anything with wheels and so on.

    How can you effectively use 3-in-one multi-purpose oil?
    The bottle is uniquely designed to give you absolute control during application to avoid spills. The squeeze bottle and drip application are part of the unique design of the bottle. It has a drip applicator with a cap attached. This ensures you apply the desired amount easily. Thie bottle has a fill level indicator strip to show you when you are running low. The product dries quickly leaving no messy residue and also minimise dust accumulation.

    How is 3-in-one different from WD-40?
    The 3-in-one penetrating oil has two distinctive spout options that allows you to lubricate parts without splatter or over spray. On the other hand, WD-40 penetrates to loosen, degrease, and clean stuck parts, so as to prevent corrosion.

    6. Kano Aerokrail Penetrating Oil
    The Kano Aerokrail is the aerosol form of Kroil which loosens frozen metal parts and threads in minutes. A scientific principle decreases the surface tension for this solvent to creep into openings small as a millionth of an inch. The product also dissolves gum, oil, dried grease and frees frozen shafts and pulleys without attacking the metal. It displaces water, prevents rust and provides lubrication. Aerokrail creeps below the fouling in barrels, enabling you to knock it out easily with a brush.
    The product is a durable lubrication which prevents further rusting by lubricating metal parts worked on. It works best for getting underneath and loosening carbon build up, lead and copper fouling in firearms.
    The product is the best solution for cleaning, loosening exhaust bolts, rust removal, drain and fill plugs. To get the best results, spray on the required surface, leave it to penetrate for a while before wiping it away.

    What is the mechanism behind Kano Aerobroil penetrating oil?
    Since not all frozen parts are a result of corrosion, molecular properties in the oil ensure that the final molecular architecture of the product is capable of loosening any frozen metal parts. This property enables Aerokroil to break bonds of rust and even loosen over torqued parts to free stuck metal joints.
    Kano Aerokrail is packed in an aerosol can for direct application. This makes it easy to access even the furthest parts. Any of the mechanical parts which are stuck together will be freed. This leaves no further reaction between the metal and solvent. The oil has a fairly distinct smell and evaporates quickly. You should be swift with your hands to minimise wastage. It should be used in open places and if this is not possible, ensure you open all windows to let air in.

    7. Liquid Wrench L106 Penetrating Oil
    Liquid Wrench penetrating oil has been used for a very long time to loosen stuck components. It is among the most trusted oil as it is tough and excellent penetrant in the market. The oil is fast-acting to quickly dissolve rust and cut through grease.
    It has high levels of solvency and lubricity and very low viscosity. The oil also has low surface tension. With such properties, it can flow into threads and very tiny spaces as well as cutting through tough rust. The product used in Liquid Wrench L106 penetrating oil are designed for common use temperatures even below 200 degrees fahrenheit.
    The oil is yellow in colour and is composed of hydrocarbon fluid, carbon dioxide, TMP Tri-oliate polyol ester. It is safe on plastic, PVC, painted surfaces and metals. However, you should avoid spraying on wood, cloth and any other material prone to staining. It has a non-pleasant smell. Windows should be opened before you start spraying.

    What is the easiest way to use Liquid Wrench L106 Penetrating Oil?
    Start with brushing the surface you are working on with a wire brush to remove as much rust as possible. It will make it easier for the oil to penetrate all nooks and crannies. You should then heat the surface with a lighter or something of similar form to expand the metal and loosen more rust. For smaller spaces, use a convenient applicator for a more precise spray to avoid spillage and after allowing it to sit for a while, wipe the surface for a new shiny look. I then heat the surface with a lighter to expand metal and loosen more rust.

    8. Royal Purple 05000 Maxfilm Synthetic Penetrating Oil
    The oil is a strong synthetic lubricant that is versatile and may be used for many purposes. It deeply penetrates, cleans and loosens stuck and rusted parts, providing a long-lasting protection against further rust, wear and corrosion.
    Prevents binding and loosens stuck parts like nuts, bolts, hinges and locks. Lubricating open gears, power tools, fishing tackle, lawn equipment, chains guns and rollers. It is used as a cutting fluid for facilitating ease of hand drilling, tapping and metal cutting of aluminium, steel and other metals.
    When the oil is applied, its solvent carrier evaporates leaving a tenacious, thixotropic film on metal surfaces, providing protection against rust, wear and corrosion. Maxfilm has a carbon dioxide propellant that is proven to make equipment run quieter and smoother.

    What is the best way to use Royal Purple Oil?
    On the working surface, be it hinges, nuts, bolts or other equipment, make sure to brush it with a wire brush to reduce level of corrosion. This also increases the penetrating ability of the fluid. Spray a thin film of the product and let it sit for a while. For the extremely damaged surfaces that have stayed for a long while in the garage, spray another film after wiping the first layer. The resulting dry film will not collect dust or dirt. It also avoids getting or gumming which may happen with other mineral-based products.


In conclusion, there are many penetrating oil brands in the market, and choosing the right model may be challenging for some people. However, this does not have to be a difficult proposition. I cannot say for sure which one will be the best penetrating oil for rusty bolts, but that is only because each one of these penetrants acts differently and may suit some people over others.
Personally, I would recommend WD-40 or Kano Kroil for most applications. In a number of comparison performance tests, Kroil prevailed against all others.
This shouldn’t limit your choices though. There are good and bad reviews for each and every penetrating oil.

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