What Is the Best Quenching Oil?

As you enter the craft of blacksmithing, you will realize that a lot of experimentation is needed in order to find out what works best. Of course, there are always basic principles that cannot be broken, but there are many different ways and techniques used in blacksmithing. So if you have 3 blacksmiths and they are making the same project, chances are that a project will be completed in 3 different ways. I would say that blacksmithing is an art, rather than science.

In the last article, we discussed the quenching process in general and the advantages of oil in quenching. If you are interested, you can check it here, Why Do Blacksmiths Quench In Oil? We get a lot of questions in regard to choosing a proper quenching oil, so in this article, we decided to answer this question in detail.

So what is the best choice of oil for quenching?

Quenching oils, such as Parks AAA or Parks 50 are considered the best quenching oils. Another popular choice is canola oil which contains a high amount of oleic fat and therefore provides excellent oxidation resistance.

Of course, it also depends on various factors, such as steel type, cost, availability, workshop location, the purpose of the workpiece, etc.

As we said earlier, a lot of factors play a role when it comes to choosing a proper quenchant, so it is of great importance to do your own research before starting. Next, we will go through the most popular quenching oil and present its pros and cons.

Commercial Quenching Oils for Blacksmithing

In case you want the ideal and proven solution without much experimentation, commercial oils like Parks AAA and Parks 50 are exactly that. They are precisely designed with some special properties with possibilities of being fast or slow quenchant for this process.

Parks AAA is one of the most popular quenching oils on the market. It is considered a medium to medium-fast oil. The Nickle Ball test result is 9-11 seconds. The most common steels like O1, 1080, 1084, 5160 are used with this quenching oil. Also, other similar steels using medium speed can be used. You will see the highest quality if it is pre-heated to 120 °F.  

Parks 50 (affiliate link) is known for its high hardness in many „water quenching“ types of steel. In the beginning or vapor stage, this oil cools similarly to water. As the cooling process is nearing its end, it starts to slow down in order to prevent undesired cracking. Because of its low viscosity, it is as effective at 50°F  as it is at 120°F.

This is a great thing for a lot of people who don’t have a quenching tank with heaters. Also, it will last longer as oil drag out is minimized. Most quenching oils have a flashpoint of somewhere around 350°F, while the flashpoint of Parks 50 is 275°F.

As long as the temperature of the oil bath does not go over 120°F, it is safe to use. It is considered a fast quenching oil. Nickle Ball quenching time is 7-9 seconds. The most common steels used with Parks 50 include 1095, W1, W2 and other steels using fast speed are appropriate.  

If you live in Europe, because of the high shipping costs, the alternative to Parks oil would be Rye Oil. They are located in the UK but also provide shipping to all European countries.

PROS of commercial quenching oils

  • Designed specifically for quenching
  • Properties for optimal quenching
  • Apposite for various speeds
  • Long durability

CONS of commercial quenching oils

  • Expensive
  • Not easily available

Are Natural and Vegetable Oils Good for Quenching?

Because they are relatively inexpensive and easily available, vegetable oils became a popular quenching option for a lot of people. You can go to a local store and get the required amount for around 30 bucks. Properties of steel can vary a lot using different vegetable oil, so it is important to know their compatibility.

Canova oil

Canova oil is the most popular quenching oil in this category. It contains a high amount of oleic fat and provides the best oxidation resistance of all vegetable oil. Canola is an oilseed that is mostly found in Canada. It is readily biodegradable. It does not have any smell which makes it an excellent choice for a home workshop.

Before quenching, you will need to pre-heat the canola oil to a slightly higher temperature than commercial oils. It also has a high flash point which is desired for this process. Another interesting fact is that the boiling temperature of canola oil is noticeably higher than most petroleum oils. These characteristics provide greater safety and reduced temperature between the boiling and convection phases.

PROS of Canova oil

  • Low price
  • Good biodegradability
  • Low smell
  • Ideal for indoor workshops
  • High boiling and flashpoints

CONS of Canova oil

  • availability sometimes

Peanut oil

Peanut oil is another popular quenching oil in this category. Like canola oil, it is basically non-toxic and bio-degradable. Also, it is needed to pre-heat it before quenching. In case you are doing quenching in a closed area, peanut oil is another appropriate choice because of low toxicity and low smell. The only negative is that it can be as twice as expensive than canola oil.

PROS of Peanut oil

  • Good biodegradability
  • Ideal for indoor workshops
  • High boiling and flashpoint

CONS of Peanut oil

  • More expensive than Canola oil

Are Mineral Oils Good for Quenching?

Mineral oils are also known for good cooling for most steels, but they are more expensive. When they tested canola oil with mineral oil, canola showed greater biodegradability compared to mineral oil. Moreover, when high temperatures are achieved, oxidation occurs, which leads to the buildup of toxic chemicals.

Be aware that with an extended period of inhalation of these chemicals, potential health effects may occur. The build-up of the same chemicals during prolonged use also affects the quality of the quenching process.

Generally, we would recommend commercial or canola oil over mineral oil for quenching purposes.

PROS of mineral oils

  • Good cooling process

CONS of mineral oils

  • Sometimes expensive
  • Lower biodegradability,
  • Not ideal for the home workshop
  • The high amount of toxic chemicals

Can You Quench Steel in Motor Oil?

Motor oil is commonly used in blacksmithing. The biggest pros are that they are cheaper than commercial quenching and also, easily available. Big chances are that you already have some in your garage, at least used one.

The bad thing about motor oil is that it contains additive and some toxic chemicals. As with mineral oil, it is recommended to quench either outside or in some well-ventilated space. During the quenching process, motor oil can also have a bad smell which can continue even during the process of tempering.

PROS of motor oil

  • Low price
  • Easy available

CONS of motor oil

  • Contains additives and toxic chemicals
  • Not ideal for indoor spaces
  • Bad smell

How Quenching Oil Is Tested?

The popular way to test a quenching oil is to make a Nickle Ball test. Nickle, as being highly magnetic, will eventually lose its magnetism at a certain temperature when you heat it. Also, it will take back its magnetism at the same temperature when you cool it.

First, a 1 inch (25mm) nickel ball has to be heated to 850°C. When the ball has achieved the desired temperature, it falls into oil. As it is dropped, it turns on a timer. The ball stands on a tray and below is a magnet. When it reaches a temperature of 350°C, it will regain its magnetism.

The faster it cools from 850°C  to 350°C, the more efficient the quenching oil is. The process is repeated several times.

Safety Tips for Quenching

  • In the case of fire, always have some type of lid and fire extinguisher near you
  • Never use a plastic container, always use a metal one
  • Never go close with your face near any type of quenchant
  • Use enough long blacksmithing tongs or some type of pliers so your hands are not close to a quenchant
  • Be careful to not quench in a cold oil
  • Always heat the oil before quenching 

Recommended reading:

7 Knife Making Power Tools for Maximum Productivity
The Definite List of Knife Making Tools for Beginners

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