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Unlock the Beauty of Timber: A Comprehensive Guide on Tung Oil


Tung oil

Introduction

Woodworking in Australia has a rich tradition, with enthusiasts and craftsmen valuing the natural beauty of timber. One key ingredient in preserving and enhancing this beauty is Tung Oil. In this comprehensive guide, we'll delve into the world of Tung Oil finishes, exploring its benefits, types, and providing a step-by-step guide on how to use Tung Oil effectively. Whether you're a seasoned woodworker or a DIY enthusiast, join us on this journey to unlock the potential of your wood creations. 

 

I. Understanding Tung Oil

 

Tung Oil 

Tung Oil has been a preferred natural drying oil for timber and other surfaces, for ages, (eons) providing a uniquely smooth finish. It is promoted for its resistance to water, and accordingly used not only for furniture but also for boat decks and timber floors.

It’s natural, versatile, environmentally friendly, doesn’t mould or darken, does not turn rancid, it’s resilient, and adds a depth of grain to the wood.

 

Our Tung Oil is pure, unspoilt, and untreated with any thinner, additives, or solvents, leaving you the full range of application options. Tung oil slowly cures to a matte/light satin look with slight golden tint.

 

Tung Oil is a natural Drying Oil which means that it dries to form a barrier against moisture.  Tung oil dries by exposure to the air, unlike polishes that usually dry by way of evaporation of the solvents.

 

This curing process, called Polymerising, is a process of cross linking or combining to form a bond between the tiny molecules.  In terms of drying oils, Tung Oil is believed to be the most impervious to water, once cured. It is also considered food safe, when cured.

 

 

II. Benefits of Tung Oil Finishes

 

Natural Finish

Unlike some finishes that mask the natural beauty of wood, Tung Oil enhances it, bringing out the intricate patterns and colours unique to each piece. 

 

Durability

Australia's diverse climates demand a durable finish. As a natural finish, Tung Oil creates a robust protective layer, ensuring that your wood creations better withstand the elements. 

 

Water Resistance

Whether you're crafting furniture for coastal homes or items meant for everyday use, Tung Oil provides a water-resistant shield, preventing moisture from compromising the integrity of the wood.


Comparing Tung Oil and another popular Oil finish - Boiled Linseed Oil

Tung Oil  

Boiled Linseed Oil     

Pure and natural oil

Has added metal compounds       

Dries harder than other oils or shellac

Not as resilient as Tung Oil

Drying time 24 hours 

Faster drying (does not completely cure)

Waterproof

Not Waterproof

Considered Food safe

Not considered food safe

Does not discolour 

Yellows 

Does not go rancid

Can go rancid      

Does not mildew

Can mildew

Retains its flexibility

Can become brittle

More expensive (than Boiled Linseed Oil)

Less expensive (than Tung Oil)

III. Types of Tung Oil Finishes

 

Pure Tung Oil

Embracing the Slow Cure - Pure Tung Oil is appreciated for its natural curing process. (Polymerising) While it requires patience, the results are worth the wait.

Tung Oil can also be purchased partially cured. Referred to as Polymerised Oil, the oil goes through a process of part drying to accelerate the final curing time. Perhaps ironically, because the oil has been partially cured, a thinner is generally added before application as the partial drying of the oil also thickens it.  In many cases, either using pure, boiled, or polymerised Tung Oil, a thinner is added to initial coats as a vehicle to aid with penetration.

 

Tung Oil Finishes

Some commercially available products labelled as Tung Oil finishes may also include additives or solvents to cater to specific needs. Choosing the right one depends on the project at hand.  Some oils (‘Danish Oil’ for example) may include driers and a mix of oils that include Tung Oil.  Ingredients are added to serve purposes not only for the finish look & feel but also to reduce re-coating and curing times. Take care also, some Polymerised Tung Oils can contain metal driers to accelerate the drying process but may void Food safety requirements.  Be sure to read the product labels carefully if using these accelerated drying solutions.

The Term ‘Danish Oil’ does not refer to an oil type but rather a hybrid finish that can be almost any combination of oils, varnishes, and solvents the manufacturer chooses.  Or even that you choose!

 

A typical formulated Tung Oil finish that you could try is to mix by 1/3rds Tung Oil, a Varnish (Polyurethane or Oil), and a solvent/thinner.

 

IV. How to Use Tung Oil

  

Surface Preparation

Before applying Tung Oil, ensure the surface is sanded, free from dust, foreign oils, or waxes.

 

Finishes start with sanding. Surfaces are unlikely to be sanded to less than 240grit prior to Oiling and maybe subject to some fine sanding during the layering process. Whilst it’s not essential to sand between coats, a slow body build may benefit from a light sand between coats, particularly where the grain may be quite open. Compromising the initial surface preparation will likely do the same to your finish… compromise it.

Before application, and between coats if sanding - ensure the surface is dust free. This can be done by first vacuuming the surface, then wiping it over with either a tack cloth or cotton cloth dampened with white spirt, mineral or gum turps.


Application

Whether you're working with native Australian timber or imported species, applicators are as varied as they are forgiving. A non-abrasive pad, lint-free cloth, or brush can be used to apply Tung Oil. Coats can be 1 or 2 or many. Factors such as prior sealing, grain, and the desired finish must be considered, but generally, 3-5 coats from new to finish, and thinned from 50/50 Oil /Solvent to 100% Oil will be applied.  It should be noted, that neither sealing the timber initially, nor sanding during coats, are essential.

 

Tung Oil is best applied in thin coats. A diluted 1st and 2nd coat can be applied, for example, at a ratio of 1:1 with a solvent. Gum Turpentine, Citrus Terpene and D-Limonene rank high among the solvents suggested.  Water is not an appropriate solvent in this instance, and it will not mix with Tung Oil.

 

Tung Oil together with lower grit surface preparations can be thinned to the desired viscosity to increase absorption (new work) and dry time.  But at some stage during coating, a 240+ grit would lend itself to a smoother ultimate finish.

 

There are mixed opinions about diluting Tung Oil with some solvents when applying the oil to kitchen utensils or children’s toys. Some believe that once the solvent has dried (evaporates) then it is no longer present and therefore food safe.  Others will advocate that once thinning with a solvent occurs, then it is never food safe.  This remains your personal choice as it is also claimed by many, that it is completely unnecessary to dilute Tung Oil to achieve better absorption. (Confused yet? 😊…. If you are unsure, test on a scrap piece, or inconspicuous area first.)

 

Apply Tung Oil with brush or clean lint-free cloth, a pad, or even your hand.  To apply a little more pressure, a white non-abrasive pad will help you to massage the oil into the surface.

 

For general interior/exterior finishes

Apply 1st coat liberally, wipe off any excess or pooling that is not absorbed within 1-2 hours. Leave until touch dry before applying a second coat. Allow 24 hours for the second and subsequent coats to dry, before re-coating.

 

Coats may vary from 2, to many for some furniture finishes, increasing viscosity (Less solvent) as coats are applied to the desired finish.

 

It is not necessary to sand between coats unless you started with just 120 grit and are ultimately seeking a smoother finish. Each coats excess or oil not absorbed must be wiped off before the oil starts to dry. This is going to be circa 15 minutes for coats after the second coat.

 

Apply thin, meaning to wipe on very thin, and not necessarily thinned with thinner or solvent - using many sparingly applied coats until you achieve your desired result.  Your best chance at achieving any natural satin sheen will be achieved using this method.

 

Burnishing

Tung oil should be applied in thin layers, and where surface sanding preparation of 600grit or more was used, then the application can be as simple as a ‘wipe-on, wipe straight off’ process. Some like to light sand between coats just to de-nib, another option is to 'wet sand' the finishing coat - wet sanding is done with fine grit paper whilst the oil is still wet. This burnishing technique may accelerate the dry time of Tung Oil, by way of heat friction and thinning. Burnishing can also result in a higher sheen to Tung Oil, without any additives.

Burnishing the finish - steps

One method to achieve a burnished finish (non-exhaustive)

  1. Apply your final coat of Tung Oil, thinned to 50/50 with solvent

  2. Allow the oil to penetrate/rest for 15-30 mins

    1. The Oil should still display a wet shine

  3. Start 'wet sanding' with 400grit - only 6 or so passes (1 pass = back & forth) are required, sanding with the grain of course. This action will cause the sanding dust and oil to form something of a slurry. It also kicks off the polymerising process.

  4. Move up the grits 400 to 600, 800,1000, 1,200 and up to 2,000 or more if you're on a roll!

  5. The slurry will slowly be removed, leaving if anything, only the finest of paste and an exceptionally smooth finish.

  6. Finally, wipe the surface (be firm) with a clean lint cotton cloth, turning the cloth to clean areas as required. You are effectively 'buffing' the surface clean.

  7. Step back - you're finished.

  8. When completely cured, your finish will be as resistant to heat and hot or cold fluids as any natural oil can be. Waxing remains an option, but is by no means required.


 

Optionally

Finishing with 1,000 grit light buff 72+ hours after final coat is dry will produce an incredibly smooth finish, however this will also lower the sheen.

 

Once cured, Tung Oil can also be waxed. Wax is an excellent way to add another layer of easily maintained protection, and to alter the level of sheen. Wax finish is an option, Tung Oil requires no additional finish, it is a finish.

  

Patience & Multiple Coats

Applying multiple thin coats, allowing each to dry thoroughly, contributes to a finish that stands up to Australia's unique conditions.  Each coat should be allowed to dry for 24 hours before the subsequent coat is applied. (Particularly if the initial coat is not thinned) Tung Oil dries from the surface down, so to apply a coat over a ‘wet’ oil does nothing to promote the overall curing process, and resilience of the finish. 

Short-changing the dry time between coats or applying too thickly can also result in a ‘gas-checked’ or wrinkled finish, which is unlikely to be your goal.  Whilst dry time will be affected by ambient temperatures, in the main, you should allow at least 24 hours drying between coats.

 

Curing Time

The curing time of Tung Oil can vary with temperature and humidity. Drying and Curing are quite different. Touch dry may be as little as a couple of hours for the first and seconds coats, particularly when highly diluted, and 24hrs thereafter. Diluting simply means to thin the Oil, in theory creating better absorption. A Solvent does not act as a drier when mixed with Tung Oil, as it would mixed with a wax.  Tung Oil both dries and ‘cures’ by exposure to the air and UV light.  Proper curing can take considerably longer. 5 to 30 days in fact.


V. Safety

 

Ventilation & Tung Oil Applicators

As with the application of any finish, ensuring proper ventilation during the application process is important. If working indoors, consider using fans or opening windows to allow fresh air circulation. Protective gloves and face masks are advisable when working with any finishes.

 

Between coats, keep applicators in airtight jars or Ziplock bags.  Ensure your Tung Oil is kept in an airtight container only removing the lid to re-charge your applicator.

 

Tung Oil applicators should be soaked in and washed out with soapy water and then laid out flat to dry before disposal. Avoid leaving Oil charged cloths scrunched up and left to dry or just discarded. Left as such, applicators are subject to combustion (Spontaneously catch fire).

 

Allergies

Tung Oil is derived from Tung tree seeds, and for individuals with nut allergies, precaution may be necessary. Tung Oil is considered food safe when cured.

 

There is some disagreement about whether it is a seed or a nut, so whilst it is possible for someone to be allergic to Tung Oil, it is not known to be associated with any other nut allergies, and so is unlikely to cause a reaction in an individual who has a peanut or tree nut allergy. Cases of allergic reaction to Tung Oil are unknown, but never say never!

 

Tung Oil Summary

Pure Tung Oil – NOT ‘Tung or Danish oil finish

Waterproof

Use on furniture, carvings, turnings, kitchen utensils, toys, flooring, and decking

Eco friendly / Food Safe  

Dries harder than other oils or Shellac finishes

Does not mould, mildew, turn rancid or darken

Uniquely high in alpha-eleostearic acid composition retains its flexibility – doesn’t go brittle or crack

Easily repairable – rub a little oil on

Doesn’t require sanding

Apply thin- not thinned

Thinner applications cure faster

Can be waxed over

Tung Oil - Special Offer

1ltr of Pure Tung Oil for only $70 with free shipping anywhere in Australia!

This offer will end 31st January

250ml/500ml of Pure Tung Oil

Still costs less delivered to your door, than any other retailers price!

(Or we'll price match!)




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