Will Linseed Oil Work Well on Plastic?

Plastics used in automotive manufacturing and around the house can become brittle, old, and dull. We know how to restore aged or dry wood with natural oils, but what about plastics? Can materials like linseed oil be used to restore plastics, as well?

Linseed oil can be used to restore brittle, old, or dried-out plastics on motor vehicles, and in other contexts, too. As plastics dry out, they can become fragile and prone to damage or cracking. Linseed oil can restore hydration and healthy oils to old plastics, but there are some surfaces on which this oil is best avoided.

Keep reading to learn more about how to apply linseed oil to hard plastics and the benefits that this offers.

What Happens When Plastics Dry Out?

Plastics are manufactured from synthetic or semi-synthetic polymers that are cured and hardened into a solid mass. These polymers are generally petrochemical in nature, meaning that they are derived from refined petroleum.

This means that plastics have a composition that is innately oily. This is the reason why plastics can be so smooth in texture, why they melt easily, and why they benefit from lubrication to look and feel their best.

Plastics that lose their natural lubrication and dry out can become dull, discolored, brittle, and can crack easily. The easiest way to restore shine and strength to plastics is with natural oil, such as linseed oil.

What Does Linseed Oil Offer?

Linseed oil is natural, is easy to apply, and won’t interact poorly with the basic composition of automotive or domestic-use plastics. Other chemical lubricants can include harsh properties that may discolor some plastics.

Linseed oil works gently yet effectively to restore shine, increase plastic’s durability and longevity by putting oils back into the material, and can also protect against the weather and scuffing.

Linseed oil can reduce the appearance of scuffs as well, and holds up well against rain and wind. It’s a very effective and weather-resistant way to help protect and restore plastics and looks especially beautiful on black plastics.

How to Prepare Linseed Oil

The most popular way to prepare linseed oil for restoring plastic involves using pre-boiled linseed oil mixed with spirits (such as paint thinner) for a 50-50 blend.

The boiled linseed oil dries a bit faster than raw linseed oil, and the spirits help thin out the oil and make the application a smoother process. Both of these products can be purchased at most hardware and paint stores, and they are safe to mix.

You can keep your linseed oil in a small plastic bottle for convenience, and keep some in your garage or shed for touch-ups from time to time. It’s a very affordable and simple solution that can help get plastics looking great again.

Where to Apply Linseed Oil

Where might you want to apply linseed oil? The most common places on a vehicle to use linseed oil would be on plastic bumpers, mounting surrounding tail lights, mirror covers, trim on the sides of a vehicle, window trim, and running boards (that little step or horizontal panel that helps you step up into or out of a truck or SUV).

What about the interior? Linseed oil is safe on plastic car interiors, as well. It can add shine, life, strength, and beauty to plastic dashboards, handles, and any interior panels or trim where the plastic needs some rejuvenation.

One safety tip: if using linseed oil to restore interior car trim, allow for ventilation as it dries. Open the windows, and let some fresh air in, as the paint thinner component of the mixture can make some people dizzy or unwell if inhaled.  Allow it to dry for 24 hours to make sure that any fumes from the spirits have faded.

How Should You Apply It?

Linseed oil is surprisingly easy to apply, and a little goes a long way, especially with the added paint thinner/spirits. Simply wipe down the surface you’re looking to restore any dust, dirt, or pollen.

Next, apply a moderate amount of linseed oil mix to a dry, clean microfiber cloth and begin to work it into the plastic surface. You should notice that just a moderate amount covers a surprising area of plastic, and you can continue working the oil into the plastic you’re restoring as you go.

Reapply oil to the cloth as needed, and buff it in using smooth, circular motions. That’s all! Now, gently wipe off any excess oil, and allow the panel to absorb the oil and dry for 24 hours.

How Long Will Linseed Oil Last?

Linseed oil does an excellent job of penetrating and hydrating old plastics. An application of linseed oil to the plastics of a car can last anywhere from 4 months to 12 months depending on weather conditions, humidity, aridity, and exposure.

Many car owners who use linseed oil find that the longer end of that spectrum tends to be more typical, but if your vehicle is exposed to intense and prolonged heat, sun, or aridity, the effects of the oil can diminish sooner.

This is why it’s generally a great idea to garage your car as much as possible, to help protect it from the elements, harsh sunlight, and even theft.  Even under less-than-ideal conditions, linseed oil can last a remarkably long time before touch-ups. Just keep an eye on your vehicle’s plastic, and reapply as needed.

Restoring Other Plastics

Apart from automotive use, can other kinds of plastics be restored with linseed oil? Absolutely. Many places where plastic needs to be restored, glossed, or hydrated can benefit from linseed oil.

Plastic garden furniture can be washed down and then buffed with linseed oil for a fresh and beautiful shine. This works especially well on darker plastics, such as black, dark green, and dark blue. Paler plastics such as white may benefit from other cleaning methods, as linseed oil can sometimes add a yellowish patina to lighter-colored plastic objects over time.

Plastics on ATVs, ride-on mowers, and motorcycles can also benefit from good linseed oil buffing. It’s a safe, natural product that can help almost any plastic material look new and beautiful again.

So long as the plastic object won’t be used in cooking or food prep, it should be safe to treat in this way; avoid treating any kind of plastic food-bearing or food prep items with a linseed oil mixture to avoid contamination or illness. It’s only safe for things like cars, trucks, furniture, and lawnmowers.

Where Should You Not Use Linseed Oil?

While linseed oil is great on plastic, it’s not as good for leather interiors. Linseed oil can be a bit harsh with leather, and this can in turn crack and damage leather seats.

Linseed oil on wooden panel interiors won’t work as well as a synthetic polish. The Wood paneling on many car interiors already has a veneer on it and is best treated with a polish rather than with linseed oil.

Another pro tip? Avoid raw linseed oil.  Raw linseed oil is more natural, but it can take quite a long time to dry, is more difficult to apply, and can be a bit thick on cloth towels. Mixing it with paint thinner or other mineral spirits is the way to go for an easy-on product that will last for months.

Other Uses for Linseed Oil

Linseed oil works great on plastics, and can also be used to help protect a car’s metal body from oxidation (rust). It’s a natural and effective barrier against moisture and corrosion and has been used by many car restoration enthusiasts working with antique or delicate older vehicles.

It’s not a great option for painted car panels but can work great on unpainted panels, or on patina needing rust protection.

What about as a tire restorer? Linseed oil works beautifully on car tires, too. Like plastic, rubber car tires can get faded, and lose their shine. Linseed oil is a simple, safe way to help your tires look beautiful again.

Staying Safe

Boiled linseed oil is relatively stable and not as prone to combustion as raw oil. Still, it’s a flammable substance, especially when combined with paint thinner.

You’ll want to store your linseed oil away from intense heat, fire, and direct sunlight as much as possible, especially in extremely hot weather. Linseed oil is harmless once cured, but in liquid form and in bulk it requires a bit of care, the same kind of care you’d use with motor oil, lighter fluid, or any other flammable substance.

If a rag or buffing cloth becomes soaked with linseed oil, be sure to wash the oil out thoroughly with water, and allow it to dry in a cool, dry place away from heat or sunlight.

Conclusion

Linseed oil is great for plastics and works well to restore and protect plastic automotive parts, as well as the plastics on ATVs, lawnmowers, and motorcycles. As plastics dry out, they can begin to look faded and are more prone to cracking.

Simply combine one part boiled linseed oil with one part paint thinner for an easy-to-apply finisher. Apply to a cloth and rub it into your plastic bumper, mirror cover, or trim. Be sure to keep linseed oil away from direct sunlight and heat, and wash it out of any rags thoroughly.

Linseed oil can be used on plastic car interiors as well as exteriors. It can also help protect bare metal from corrosion, and lend shine and durability to the patina as well. Avoid using it on leather, finished car paint, and wooden panel car interiors.  Finally, avoid using it on anything used to serve, eat, or store food.

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