What can I cover with tung oil?

 With tung oil having such a long history and record of use the question is quite broad and too large for a simple answer, so to start off we should break this down to a few categories first.

  • Interior uses.
  • Exterior uses.

and

  • Pure Tung oil finish.
  • Commercial blend finish.

Understanding the difference between the pure and commercial mix is important now before we progress further into the question.

Pure tung oil

Pure tung oil is just what it states and is the liquid that is extracted by pressing the seeds harvested from the Tung tree, a tree crop originating in southern China. It is a honey colored heavy liquid that dries by exposure to oxygen in a process called polymerization and forms a hard protective barrier.

 Commercial Tung mixes are formulas derived from a varying amount of tung, rumored to be as low as 3% in some (discovering the factual data is hidden behind proprietary information arguments and that’s to be expected) and other ingredients such as filler oils like linseed/flax and chemical/heavy metal driers to cure the blend faster.

Most of these blends are attempting to do several things. They want to give the mix a high level of toughness and they want it to dry quickly.

Irrespective of the blends and the additives used what is generally accepted is that pure tung oil is only a part of the recipe and it can be lucky dip if you are looking for a food safe or child safe finish.

We can now look at the attributes that pure tung oil holds and apply them to the list above.

The beneficial attributes of natural tung oil

  • It Dries 100%
  • The seeds are harvested as a crop so it is sustainable
  • It is non-toxic making it food safe.
  • It is very easy to apply.
  • It has no VOC levels.
  • It is safe for children’s toys.
  • It is water resistant and arguably water proof.
  • It is very easy to repair and overcoat.
  • It gives a matte finish.

 The negatives to using natural tug oil

  • Cost
  • It has been said to have possible allergy issues in extreme cases * (see article end)
  • Limited Shelf life if not stored appropriately.
  • It needs thinning in most applications
  • It takes time to harden completely ( heavily environment dependant )
  • It is not super hard. It will not wear well in high traffic situations.

 So, back to the original question.

What can be covered with natural tung oil?

Anything wooden that is in contact with food can be covered with tung oil, as can light construction timbers and wooden garden items.

Light wear furniture can be coated with natural tung as well, and it will benefit from applications of wax polish from time to time.

Book shelves can also take natural tung with careful attention to making certain the oil has hardened completely. Apply oil to a test piece while oiling the book shelf and monitor the hardness. Soft uncured oil could glue your books to the shelf if premature. Hard oil is completely satisfactory.

By applying the above lists and attributes we can work out that kitchen utensils like wooden spoons and bowls, rolling pins, display pieces such as hand turned wooden centerpieces and vases, display platters, and fruit platters and bowls all fall into the category of safe and applicable.

We learned many of these facts as we  progressed in building our woodworking business and having successfully sold our products to people from all over the globe.

If you are looking for more information we have an article expressly addressing how to apply tung oil as a food safe finish here.

It will open in a new tab and shows how to go about looking after an already finished item, then goes into how to apply oil to a raw timber item.

It was written to go hand in hand with this article and to help provide a structured approach to tung oil finishes.

A collection of wooden utensils covered with tung oil.

Staying indoors, we can also apply tung oil to musical instruments, with the disclaimer that this is best completed by someone who has experience in applying finishes to delicate and refined objects.

If you are looking at refinishing something like a guitar then natural tung can be used but again, experience will help here as careful sanding and surface prep work are required and it is all too easy to over sand an edge and damage the body. It would be best applied to a project guitar that is still in its raw timber state. That is where natural tung will shine.

a scratched floor with commercial tung finish applied many years ago.

With the indoor pure oil list attended to, we can now move onto the commercial blends for indoor use.

The most popular use for these is on timber flooring. It is in these high traffic hard wear environments where the commercial blends do well but even they eventually require attention like the image here.

This is a commercial blend applied to this floor 17 years ago and now needs some love.

It will require a heavy sand back and a fresh application. The house will need to be vacated for a day for the VOC’s to clear. It can be worth the trouble though as the finishes typically give a soft looking oil-like lustre while providing a polyurethane toughness that is required. It is the best of both worlds

 The point to press here is the VOC component of these finishes.

Some fumes can be bad and something you don’t want to be around until the finish cures. Another thing to consider is that many of these blends are specialist coatings that floor sander teams use. They are professionals who use these blends on a daily basis and know the tricks of the trade and know these blends are not as forgiving as the natural oil.

If you get it wrong you can have a major job sanding it back and starting again.

The usual drying times are overnight before light traffic.

These blends are also appropriate for kitchen bench tops and bathroom vanities. For recoating as needed over time, it is best to get hold of the product data sheet for that blend and follow the instructions to the letter.

If you are considering applying one of these commercial blends to your musical instrument then consider traditional alternatives before jumping. Nitrocellulose lacquer is used in the instrument industry for a reason.

Pegola post and rail needing tung oil finish

Tung oil as an external finish.

Natural tung oil has been used historically in maritime applications, typically cited as Chinese ships being waterproofed with it. This historical context gives us clues to the oils ability to withstand harsh conditions associated with the outdoors.

We have personally borrowed from this information and have used natural tung oil to coat and preserve hardwood timber posts of a pergola that hold up passion-fruit vines.

It is holding up well after only receiving a single coat. The great thing is when it comes time to re-coat all that needs to be done is find a ladder and a paint brush. There is no sanding required. Looking at the image reminds me I need to get this done. It looks thirsty.

It will need to be recoated more frequently than a commercial blend but the ease of application is a no brainer for us.

It also gives us valuable reference material that we can share here online. We try to live what we write about, and this is just one example of that process.

Timber gates are a great item to use natural tung oil on. If you consider the way any oil behaves when you apply it to a piece of wood, you see that it soaks in. Now, with that observation and the known fact of tung drying completely, it stands to reason that if you can get a good amount of this oil inside the wood before it goes hard you have a pretty good chance of that piece of wood being able to withstand a level a harsh treatment for an extended period of time. Expanding on this you can apply this coating to garden furniture and wooden planter boxes as well. Wooden decks could be an option but as with the flooring in the internal uses further up the page, consider the foot traffic before applying it. You may want to consider something tougher.

This list of attributes relates to the commercial blends generally speaking.

Positives

  • Can be extremely hard wearing
  • Can be extended periods before recoats are needed
  • Can give a high gloss

 Negatives

  • The smell. Some of them have VOC levels that can make you feel nauseous.
  • Difficult to apply in certain situations
  • Cost
  • Cleanup is not environmentally friendly.
  • May require sanding for recoat if aged. Very likely actually.

The commercials apply mainly to wooden cladding and decking/flooring systems. While the end finish will be tougher in some aspects, often there are downsides. Most will require heavy sanding before a recoat. Some will even dry similar to paint and not penetrate into the wood to give the protection you expect. If this is the case, particularly where the sun exposure is great, you will see the coating crack and peel over time and that is something an oil finish should never do. No finish will last forever, but planning for the future can help.

Outdoor tables can benefit from the hard mixes as well as stair treads and stringers however stair treads can be slippery if just coated with a gloss finish.

To finish up, the primary considerations are

  • What is needed to be coated.
  • Where is it typically located?
  • How much traffic will it take?
  • Will it need to be easy to recoat?
  • How safe does it need to be…child related.
  • How much time can I give it to dry?
  • How environmentally sound do I want it to be?
  • How much experience do I need to apply it?

 When you apply the list of questions above to your situation at hand, you can quickly conclude the application that best fits your situation and you can answer your own question. You now know what you can cover with tung oil.

If it is indoors, needs to be food safe, and will be used in food preparation then pure tung oil is required.

If it is the kitchen floor where you need  heavy foot traffic protection then maybe the commercial blend is appropriate.

Timber joinery like windows and doors are a mix of both depending on the situation. If the eaves protect the outside of the windows and they don’t get that much weather then pure oil could be considered. If they get a lot of sun and rain then either a commercial mix or painting in traditional coatings might be appropriate. 

 *

A safety point to consider for using tung oil in any situation.

There have been online discussions regarding the safety of tung and the issue of nut allergies. While we will not take a side in this conversation we will state that pure tung oil does dry 100% hard and becomes inert once it has achieved this state.

The oil is derived from a seed of a tree and not a nut, but note that that statement of fact does not magically translate into safety for all. Uncured or liquid tung may well be a problem for some people and to cover the bases it should be said that you really don’t need to be drinking the stuff in a normal situation. We can’t imagine why you would want to be doing that at all, but that’s just us.

Treat the liquid oil with care and respect and you should be ok. Particularly once it has cured. Now, go and plan you project and make an informed choice based on the above. You will do fine.

Article written by Tim Blanch as part owner/operator of Pickers Ridge. He is a trade qualified Carpenter/Joiner with over 30 years experience in construction, amongst other skills.