Whether boiled or raw, linseed oil is often only mentioned when it comes to finishing woodworks. But the truth is that linseed oil works on metal too. Many metal workers love to use it as a finish for their projects, whether for restoration or a simple modification.
While raw linseed oil can be used, many DIYers often wonder: Can you use boiled linseed oil on metal?
In this article, you’ll find the answer to whether you can use boiled linseed oil on metal. You will also learn:
- What boiled linseed oil really is;
- Some great ideas for applying linseed oil;
- Some vital points to keep in mind when working with boiled linseed oil.
Continue reading to find out!
What is Boiled Linseed Oil?
The name “Boiled Linseed Oil” can be confusing. It is called Boiled Linseed Oil but technically speaking, it is not boiled. It is chemically treated and modified with hot air, chemical additives, and some metallic solvents. The goal of this modification is to shorten the curing time.
Raw linseed oil takes as much as a month to cure, especially in cold weather conditions fully. But Boiled Linseed oil is chemically modified to dry in a few days.
Can You Use Boiled Linseed Oil on Metal?
Yes, you can apply boiled linseed oil on metal. Although many sites and forums online and even marketing efforts deceptively label linseed oil as a wood protective coating, it can be used on metal.
When applied to metal surfaces, it helps to protect them by preventing oxidation. This means, in simple words, that the boiled linseed oil prevents the chemical reaction between the metal and oxidizing substances such as oxygen.
Normally, when a metal surface is exposed to the atmosphere and the elements for long, it begins to rust. This metal rust is called iron oxide. It is a brownish-red oxide that forms due to the reaction of iron and oxygen in the presence of moisture.
Rainwater or moisture in the air works as a catalyst to increase the rate of the chemical reaction between metal and oxygen. Boiled linseed oil works to prevent this chemical reaction and, by extension, prevent your metal from rusting. So yes, it is a great idea.
Some Good Ideas for Applying Linseed Oil on Metal
Bake the Item in an Oven
This is one great way to use boiled linseed oil. Baking the boiled linseed oil on the metal will give it a shiny amber sheen and also work as a rust inhibitor to increase the lifespan of your tools.
This idea works great for non-moving parts of metal work tools like screwdrivers, clamps, and saws. But be sure to remove non-metal parts such as plastic and wooden handles before baking them.
Apart from being a rust inhibitor, the coating will also become scratch-resistant, keeping your tools looking brand new for as long as possible,
The first step for this great idea is sandblasting the metal item. This step is important because sandblasting helps you remove the oxidation deposits from the metal item. It removes the paint, the rust, and dirt so that the oil makes contact with the surface of the metal. You want to sandblast the metal until you get off all the residues. The metal is ready for the next step when you get a sort of matte finish.
After sandblasting the metal item, the next step is to coat it with the boiled linseed oil. Coat the metal with the boiled linseed oil and cover it with aluminum foil. Since you already sandblasted the metal, you can be sure that the nooks and crannies will be filled with the boiled linseed oil, and no dirt will come into contact.
After coating the metal with boiled linseed oil, you want to leave it in the oven to bake at about 400°F for an hour. The result should be a nice dark amber-colored tough coating. In many instances, the coating is even tougher and scratch-proof than high-quality paints.
If you are unhappy with the result, you can repeat the coating and baking process for a darker and tougher sheen.
If you are working on bolts and screws, you can take it up a notch by applying a little bit of the Super Blue gun bluing solution to give it a darker and more attractive look.
But remember that if you are applying boiled linseed on your metal working tools, it is better to apply boiled linseed oil to non-moving parts of the tool. You can use it on your metal handles before fixing them in place. You can also apply the oil to the metal part of your handsaw.
It would be pointless to spend so much money, time, and effort coating moving parts only for the friction to wear off the coating.
Spray and Torch-Bake
This is another great idea for using boiled linseed oil; spraying the oil on the metal item first and then using an acetylene torch for baking it in the open. Using a weed burner is another option, but the choice depends on the nature of the item you are working on.
The acetylene torch will naturally give you more precision on the item you are working with, especially if you are working with a metal item that has many nooks and crannies. But if you are working with something that has broad surfaces like a metal board, you can use a weed torch since it blows with wider coverage.
The first step is to clean the item. Again, you want to ensure that the item you are working on is free of residues and dirt that may block the contact of the boiled linseed oil. You can do this by sandblasting the item.
After cleaning the item, the next thing you want to do is spray your boiled linseed oil over the metal item. Alternatively, you can use a rag. Many DIYers prefer rags because it helps them manage the oil thickness on any part of the item they are working on.
If you use a spray gun, you want to set the control well to allow you to spray only the amount needed. It would be best to pay attention to the quantity of boiled linseed oil that will be sprayed to avoid a runny coating.
Using a brush for application is not recommended. It will leave streaks and a runny coating. This will ultimately result in a gummy. Use a spray gun set appropriately or a rag.
After applying the boiled linseed oil, get your acetylene torch and bake the metal item carefully until you get the desired sheen. You can also do this with a weed burner.
For items with no nooks and crannies, you can go ahead ad blast the heat with a weed thrower. You only have to connect the weed torch to the gas feeder, light the torch and bake away. Pay attention to the control. Blue flames supply more heat than yellow flames.
But if you are working with a metal item like a metal sculpture with lots of bends and curves and details, an acetylene torch would be perfect. This will help you get the heat to every nook and cranny of the item.
Note
- To have a great finish, you want to avoid thick coating. A thick coating is not ideal. It will result in a build-up of the oil on the metal surface. This is sometimes called “Gummy.” You can apply as many coatings as you like to get your desired thickness, but you must leave a curing time between the coatings to avoid a gummy.
- Pay attention to the product’s recommendation. Some products have a recommended curing time. Using a brand like any other brand could lead to poor results. You want to note the manufacturer’s recommendations when using a product.
- Most importantly, pay attention to safety rules. Buffing rags used to apply linseed oil, whether boiled or raw, have been the cause of fire outbreaks in many houses. The rags can heat and become combustible due to a lack of ventilation and heat. You want to dry the rag and leave it on a non-flammable surface.
It is also important to use protective gears when applying the boiled linseed oil on an already fired metal work. Unlike the coat and bake style, toxic fumes emanate from the already heated metal items immediately after you apply the boiled linseed oil.
Final Thoughts
Boiled linseed oil is an excellent natural finish for protecting metal. It works as a rust inhibitor to prevent the metal from rusting as it serves its purpose in the presence of moisture and oxygen.
As you try some of the great ideas in this post, it is pertinent that you work responsibly in safe working conditions. Be careful with the torch and ensure that you use gloves to avoid getting burnt by the hot metal.
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