One of the most frequent questions that we encounter is how to seal a traditionally made didjeridu - or indeed, if to seal it at all.
While the latest didjeridus made by traditional craftsmen may have some sort of sealant on the outside (commonly diluted PVA glue) and the artist may have used acrylic paint, many instruments, especially older ones, are painted in ochre (earth pigments) and have no form of sealant whatsoever.
So what are the options ?
Leave it as it is.
Purists and collectors often consider that any work done to a traditional instrument by anyone other than the maker (or artist) impinges on the authenticity and intrinsic value. This is something which everyone will have to consider for themselves.
The disadvantages of leaving an instrument untreated are as follows:
- Ochre artwork is extremely sensitive and rubs off very easily
- An instrument which has an untreated bore is prone to cracking. The longer it is played, the more likely it is to crack: tension is created in the wood because the expansion of the bore caused by moisture is not matched in the wood on the outside of the instrument. More info on the ambient humidity page.
Artwork on traditional instruments is usually ochre, ochre mixed with diluted PVA, or acrylics.
Ochre artwork, even that mixed with glue, will often easily come off on your hands. If you can live with that, fine. If not, you're going to have to seal it. The problem here is that because the ochre has no fixative, it's very sensitive to moisture too, so if you try to put anything over the top to seal it, you may end up doing more harm than good because what you're applying makes the artwork run. Be extremely careful what you use, and test a small amount on a small, inconspicuous area to see what happens. Whatever you do, never try using a paintbrush to apply anything to ochre artwork !
We recommend using a water-based acrylic matt varnish which has a minimum of solvents. It is essential that it's very quick drying (a minute or two) on ochres, otherwise it may run : it's also necessary to apply it very thinly and evenly, building up several layers. The first layer in particular should be as fine as possible. The easiest way to do this is if you can find spray cans of something fitting the above description in your local hardware shop. It's important that the spray is a fine mist. If in doubt, consult a specialist.
Serious Sticks instruments all have their artwork sealed as necessary - unless we get a special customer request. The varnish we use provides a moderate protection which is undetectable to the eye - but doesn't replace the need for gentle handling and care.
Please feel free to contact us with any questions you may have about specific instruments. There is no rule which is 100% reliable and effective for all instruments.
Sealing the bore
An unsealed natural bore looks dry and dusty. It is!
We recommend oiling the bore. Oiling affects the sound minimally if you use well-penetrating oils, and still allows the wood to "breathe" so that the level of moisture in the wood can adjust slowly over longer periods. Varnishing will unnaturally brighten the sound and may also cause problems if moisture gets in through a small area which was unintentionally left unvarnished and can't easily get out again.
What oil to use? There are numerous theories here, all with their own merits and disadvantages. We use a mixture of tung oil, linseed oil, orange oil and eucalyptus oil. Our experience shows that this provides a good compromise between oils that set really hard, almost like varnish, and thin oils which never really dry properly and can in some cases become rancid or infested with fungi.
How often is it necessary to oil an instrument? Well, that's a tricky question, because it rather depends on how much use an instrument gets, both how long and how often. As a general rule, we suggest oiling 2 or 3 times a year. Oiling for Winter, when the air is much drier, is doubly important.
How exactly do you apply oil to a didjeridu anyway? Detailed instructions HERE