Penetrating oil is a liquid used to help release mechanical parts that have stuck due to various reasons, the most common being rust. Penetrating oils are made up to two chemicals, one to react with the rust of other corrosion elements and the second is oil based on coating the surface of the part allowing it to slide or move easily.
Many penetrations are used for more than one purpose, some to reduce sticky hinges, others to clean and protect greasy ferrous based tools and equipment. These oils come in two forms, a free flow can and a pressurized aerosol container.
- Here is my list of the top 12 penetrating oils
- 1. Kano Kroil Penetrating Oil, 8 oz. liquid (KROIL)
- 2. LIQUID WRENCH L106 Penetrating Oil, 5.5 Oz
- 3. WD-40® SPECIALIST® RUST RELEASE PENETRANT SPRAY
- 4. Kano AeroKroil Aerosol pressurized Penetrating Oil
- 5. CASTLE® THRUST™ PENETRATING OIL
- 6. LOCTITE LB 8201 Lubricant – multi-purpose oil. General purpose
- 7. 3-IN-ONE® Multi-Purpose Oil
- 8. PB B’LASTER PENETRANT
- 9. Knock’er Loose® Penetrating Solvent, 13 Wt Oz
- 10. LIQUID WRENCH® Lubricating Oil with CERFLON®
- 11. Kano Labs SiliKroil – Kroil with Silicone
- 12. Maxfilm® Multipurpose, Synthetic Lubricant
Here is my list of the top 12 penetrating oils
There are slight differences in quality and price, but all of these products have been tested and found to work extremely well. At the end of this review article, I have posted two bonus articles, one on how to remove rusted bolts and the second is a review of natural household products that can act like penetrating oil when you don’t have access to penetrating oil.
Kano Engineering is an old and reliable American company that has supplied various products to heavy industry and the automotive sector for over 80 years.
This is Kano’s Kroil, penetrating oil that will hit any corrosive impediment and break it down, allowing the oil to act as a momentary lubricant, releasing the stuck and rusty bolts or parts quickly, easily and efficiently.
I include some Kano Engineering products here, because, in my humble opinion, they are the best in the market, while not well known, their products are high quality and worth over dime you pay for them. This is their free liquid version, useful for direct application without the worries of a pressurized can.
Liquid wrench is another fine American company that produces proprietary products,. In this case, it’s their biosynthetic oil that has been paired together with their trademarked bio-degradable Cerflon® chemical that penetrates and lubricates the parts, as well as reduce and friction heat.
This particular package comes with their nifty little FlashSight™ Technology which is basically a small LED attached to the spray zone so you can see where you are applying the oil. This is actually a very good addition, especially useful in the dark recesses that are hard to see, never mind reach.
I don’t think there is a need to introduced WD-40, this is perhaps the most popular globally acclaimed penetrating oil. I think that WD-40 has reached every country around the world.
This is the WD-40® SPECIALIST® VOC compliant spray that uses their proprietary Blu Torch® Technology. Blu Torch® is a special blend of chemicals that work together to provide the fastest breakdown of corrosion impediments that enable a fast and effortless release of the stuck parts. This spray also lubricates the surfaces for a longer period.
Back to Kano engineering and their Aerosol Kroil version. As mentioned above, this is Kano’s Kroil, penetrating oil that will hit any corrosive impediment and break it down, allowing the oil to act as a momentary lubricant, releasing the stuck and rusty bolts or parts quickly, easily and efficiently. I include some Kano Engineering products here, because, in my humble opinion, they are the best in the market, while not well known, their products are high quality and worth over dime you pay for them. This version is packed in an aerosol for direct application to easy access parts.
Castle® Thrust™ is an ion-activating substance, which basically means it will react immediately and for as long as the impediment has not been broken down. The Castle® Thrust™ penetrating oil will foam for a long time, so don’t start applying pressure until the foaming has completely stopped. If you need a lot, you can apply this product with a brush directly to the stuck parts.
Another world famous product, a direct competitor to WD-40 is the German LOCTITE LB 8201. This is their universal penetrating liquid that also applies a small film of lubricant to maintain a smooth operation after cleaning the stuck surfaces.
What I like about 3-IN-ONE® is that it’s the oldest US company processing penetrant oils and they always strive to improve. They have been around since 1894, so they have over 100 years of experience with this product. This is their standard drop by drop version, its useful to both clean and lubricate stuck surfaces. This is a preferred product for bikers and street racers.
PB B’Laster penetrant is another fine US company that has been around for over 60 years. This company has a solid following of believers, and their penetrant works wonders. This particular brand is popular for marine fouling and is found all along the US coastline.
If you are looking for fast acting, no-nonsense home release product, then look no further. Knock’er Loose® is a great spray on penetrating oil that can compete with WD-40 and Loctite any time and is great for all your rusty or squeaky hinges and stuck bolts. Its very low viscosity provides effectiveness in reaching very thin layers.
This is LIQUID WRENCH® lubricating oil that is also useful for stuck parts. After you have released the stuck part, clean the surface properly and apply this oil, you will maintain a squeak and stick free environment for a very long time. It also includes their proprietary CERFLON® solid-state lubricating coating.
How can I not include another fine Kano engineering product? This is Kano’s Kroil with silicone added for extra water and marine applications. If you are working in a humid, wet or seawater environment, then SilKroil is the best penetrant you can hope for.
With its ultra-small molecular structure and dimethyl silicones, SilKroil is a must on every boat, ship and even garage. This liquid is also used as a cutting fluid for various metals including aluminum and steel.
My final choice, and by no means least impressive is Royal Purple Maxfilm. This amazing penetrant comes with a thixotropic lubricating film that covers the surface of the treated area and includes their proprietary Synerlec® which is a CO2 propellant that helps smooth the surface film and reduces friction when releasing stuck parts. This liquid is also used as a cutting fluid for various metals including aluminum and steel.
Bonus Tip #1:
Tips on How to Remove Rusted Bolts
Anyone involved in the industry, or automation will come across a rusty bolt, a stuck part, a corroded piece of equipment. At home, we all have had to deal with rusty or squeaky hinges and small nuts and bolts that are stuck fast. Here is a small compendium of tips aimed to help make life a little easier when finding yourself in that annoying and frustrating situation.
Deciding if the bolt is Salvageable
All materials have a tensile strength, this means that they will withstand a certain amount of pressure before breaking or tearing. What you have to ascertain aforehand is where the bolt is rusted down to a thread, or if it is retained with a locking fastener, or whether the part it is attached to is sound.
If a locking element is found, you can ease that open by applying heat. The application of heat will expand the metal and allow you to release the bolt.
If the bolt is rusted, check to see to what extent. Clean it up with a wire brush and check the surrounding area. Apply some pressure, but not a lot, and see what budges. After this apply some penetration oil and try again. If the bolt is held fast, you need to decide whether it is worth saving or not.
In most cases, a rusted bolt has lost most of its tensile strength and breaking it off, or drilling it out might be a better solution.
Small bolts and screws are most often not worth fighting over, and it is quicker and less frustrating cutting them off.
Cleaning off the rust
If you have decided that the bolt is solid, and has a good tensile strength, brush off the rust. After you have cleaned all the surfaces that were infected, brush off the base of the bolt (if it is visible). A clean base (end of the bolt) will reduce sticking when trying to unscrew it.
Choosing the right tools
Don’t blame the tool, it will only perform as well as the person wielding it. Make sure you choose the correct tools, this will reduce frustration and also focus the issue on the bolt and not the releasing process. In some instances, the head of a bolt can be worn away from rust, you might consider choosing a smaller gauge socket or wrench.
Remember your directions
Always remember that right is tight, the left is loose. You just need to remember the right is tight rhyme, the rest is simple. There are exceptions to the rule, so if you find a blot that doesn’t budge, check one that does and see if the right is tight rule fits it, by turning it left to release it.
When you face certain large bolts or bolts and nuts that are in places too awkward to reach for cutting off, you will need to apply a penetrant oil and wait until it has seeped into the surface of the bolt. Don’t rely on one type of penetrant, keep at least two different types and alternate if the bolt proves to be extra stubborn.
If the sparse application of the penetrant doesn’t seem to work, then drown the bolt in penetrant oil. Don’t be sparse or stingy, apply it like a torrential reinforce and pour it all over the infected area. You might want to leave the bolt soaking a couple of hours, or even overnight.
When some bolts prove to be extremely annoying, for instance, replacing a tire. Use leverage, take a strong pipe or other mechanical leverage options, and wear gloves. Apply pressure carefully, you don’t want to destroy the bolt while trying to release it. Try pumping the bolt as well as applying constant pressure. Pumping sometimes helps release incrementally.
A breaker bar or long-handled ratchet will give more leverage. Use a steady, even pressure paying close attention to the feel or each turn. If the tension suddenly becomes soft or rubbery, you are either breaking the bolt or stripping the threads. Wear padded mechanics gloves to reduce skinned knuckles and the number of quarters put in the swearing jar.
Heating and Firing
Some nuts can be released when eating is applied, causing the area around the bolt to expand. However, don’t use this in a confined area, and beware, penetrant oils are combustible. You also have to take care that no plastic or rubber parts are in the direct heating zone. A focused oxyacetylene torch is best when applying heat around a bolted area.
Some rusty iron parts can be released by heating the surrounding area and then melting a candle over the area, the paraffin wax acts as a great releasing mechanism. This is a good solution for threads as paraffin finds its way all along a threaded surface.
Breaking the Bolt
OK, you have tried everything, and nothing goes, there are two options, give up and get a new whatever, or break the blot with a pneumatic drill or strong hammer. If possible even grind or saw the head off. Then drill into the body of the bolt and removing it by eating it from the inside out.
Bonus Section #2
Natural alternatives to penetrating liquids
If you don’t have access to a penetrant, either because you are stuck in the middle of a desert or a mountain, or perhaps it’s the middle of the night, and you ran out of it. There are some possible solutions. A research study performed by Engineering students at Drexel University in Philadelphia found that a mixture of 12.5% acetone (nail varnish remover) and household vegetable oil, will provide the same if not better performance than WD-40. This little tip is very useful for solving some of life’s bigger mysteries such as a squeaky door at home.