Howdy Keeth.

If you are interested, here is a walkthrough of how I coat some of my sticks.

www.didgeridootribe.net/clan/index.php

Since this description uses commonly used substances and processes, it is best to not talk about it here in alternative land.

There really is not a lot of debate on finishing amongst woodworkers. The properties of finishes are well understood. 'Natural' finishes work well for many uses. Their only drawbacks are also their strengths. For example they wear much easier. They will not look 'new' for as long. The upside to this is that they are easily recoated. They wear easier because they are not as hard and are also thinner. The upside here is that the wood is right in your hands. It feels good and looks good. The downside is that they are not as protected from water, moisture, or impact. Oil and wax finishes are universally understood to provide very little protection. Important to note that protection is not always a primary concern!

The most commonly used natural finishes are 'hardening' oils and waxes. The hardening oils do not exactly 'dry' they polymerize. This process takes in the neighborhood of a month. Thinning these oils with a natural thinner, such as Citrus oil, will simply apply less oil. Basically the oil will be suspended in the Citrus thinner. When wiped on the Citrus oil evaporates quickly, leaving far less Hardening oil to be wiped off. It does not help it 'penetrate', nor will it cause it to polymerize sooner. This is the same usage/property of Mineral Spirits.

Most oil finishes are applied in numerous layers. Ancient Tung oil finished wood has been found in China with hundreds of coats on it. I have found with pure Tung oil on dense, tight pored woods, a minimum of 5 coats is necessary to have much(if any) protection. This is where you will start to see a gloss to the sheen as well.

Open grained/pored woods will be harder to oil. More oil will pool in the grains and take much longer to cure. Traditionally this wood would have a sanding sealer applied to fill the pores before oiling.

Many oil finishes will have a wax applied as well. This, like the oil does not hold up as well as a Varnish, Shellac, Lacquer, or Resin, etc.

There are also natural Resin and Shellac finishes. This will almost universally be applied using Mineral Spirits or another thinner. These evaporate and are considered by everyone outside the loony bin to be inert when cured. You would not want to take a swig of all natural Citrus oil so there is also that. Also, last I checked Mineral oil and its distillates are 100 percent natural. Then again so is Uranium..

Basically, so long as you are aware that Oil based finishes are considered to be the weakest, least protective and shortest lived finishes, you are golden. Please be aware that they are also frequently described as beautiful! Woodworkers generally use an oil based finish for something that will be lightly handled, or constantly maintained. A little desktop knick-knack? Great for oil. A cutting board, where the finish needs to be thin as well as easily re-applied? Great for oil (usually mineral oil and melted wax). A Clarinet where the wood needs to breathe and have a thin finish? Great for oil(reapplied very regularly). It is also usually made from Ebony, an incredibly dense hardwood, not a porous reed.

Anyway, Yucca needs something reflective, non-porous and relatively strong inside it. All natural and you are stuck with a Carnauba or Beeswax finish for the interior. No oil will be hard enough, or thick enough. If you removed every bit of softness in the Yucca cane and heavily coated it with Wax, you might get a tolerable sound. Sounds swell huh? With wood you could get a great sound with only a hardening oil. Assuming a good bore profile and a hard enough wood.

So for a Yucca/Agave, something thicker and harder needs to be applied for sound and strength. That is going to be a urethane, which is arguably way too thin. A wax, which will be muted, muffled and not too strong. A glue which will be thin and not too strong. A glue mixed with something to be thicker, denser, or more strong. Be aware that adding powders to glue will not make it stronger. It will make it denser and possibly more acoustically reflective. But not stronger. Arguably it could be weaker. As an example I offer up Plywood/OSB and MDF. Plywood is the strongest. Big sheets of wood glued to other sheets. Much stronger than the same thickness of solid wood. OSB, lots of chips and flakes glued together under pressure, much stronger than solid wood of the same thickness. MDF, powdered cellulose in a glue matrix under pressure. Less strong than wood or glue of the same thickness. It is easy to break, crumble and is more permeable to gasses and liquids. This is also why Carbon fibre is layed up in flakes/chips or sheets, instead of a powder.

Anyway, here are you options for the interior of Agave/Yucca.

Epoxy - thick and reflective. Adds strength and is acoustically reflective. Few coats needed. Inert when cured. If you know the difference between exposure, and OVERexposure, you should be fine.

Beeswax - easy to apply, smells good and is natural. Thick coat. Minimal to no extra strength. Not much more reflective than the original Cane. Probably wont sound good relative to other instruments. May break easily. Blending Paraffin will improve sound a bit, but not much and will no longer be 'natural'. Whatever the hell that means! Carnauba is a natural hard wax, it is what I use. When I rarely use wax, that is.

Glue - easy to apply and will be acoustically reflective if lots of layers are used. Like 5 or so, especially if it is watered down. Adding powdered whatever will thicken it and should alter the tone depending on thickness/density. I don't think you will be adding a ton of strength, but honestly Epoxy does not add a ton of strength either. Yucca and Agave are not wood. They are very straight grained and are in the neighborhood of Balsa as far as strength. They split very easily and if dropped hard enough or stepped on, they can break no matter what is on them. More flexible glues and Epoxies will help, very hard Lacquers or Enamels would not be a good choice.

Polyurethane/Acrylics/etc. - these finishes are all going to be quite thin and not very strong. Some of these require good airflow to evaporate the carriers. The inside of a Didj does not have good airflow. These are poor choices in my opinion, but they are easy to apply. I would use a mineral spirits born poly, if I had to use these finishes inside a Cane. i would also pull air through for a few days with a fan.

I suppose you could melt some metal and pour it inside, barring that those options are about it.

If it were me I would use an Epoxy. USComposites, Envirotex, or West Systems. The long cure and 1:1 ratios are easier to work with and less smelly when curing. Buy an appropriate respirator, work with good ventilation, wear some eye protection and some gloves. Don't take a bath in it and don't drink too much of it and you will be fine.

Next choice for me would be glue. i would use Titebond 3 and personally would mix in shavings from my planer and jointer. I would use extensions and sand inside between coats. Basically making a layer of OSB inside the didj. I would do a minimum of three coats. You could mix water in to thin the substance if needed. There are countless ways you could do this, if you try it, let us know what you do!

For the outside, natural to me would mean a hardening oil. These are generally Tung oil or Boiled Linseed oil. Most other oils will go rancid. Mineral oil is non-hardening and could also be used. Tung oil is considered to be the most protective of the hardening oils. Important to note that it is also considered to be one of the least protective finishes. These are not my opinions, there are countless scientific and anecdotal studies that prove this. There is virtually no debate about any of this either, again amongst woodworkers/cabinetmakers/furnituremakers and the like.

The blend I use is 30 percent Citrus oil 50 percent Tung oil and 20 percent Boiled Linseed oil (BLO). I then use a high quality furniture wax. Almost all commercially available waxes will have a thinning carrier(mineral spirits). This evaporates and is near universally used. I have had luck thinning my own Carnauba wax with Citrus oil and low heat. You could also skip the oils and just use wax. Or blend beeswax into a matrix of oils.

When applying oil finishes, I heavily wipe the oil in, and let it stand for 30 minutes or so. I then vigorously rub the wood to remove all excess oil. Then I wait a few weeks before applying the next coat. I always gently sand with 0000 grit plastic wool between coats. The more coats the better. Once it starts to build you can reapply every 4-10 days depending on your environment and how heavy a coat you apply.

When you like the finish you can wax it or not.

Anyway, there is one 'natural' way of coating wood. I would only use this technique on very stable and sound, 10 percent or lower moisture content WOOD. I might use it on the outside of an Agvae or Yucca cane, but probably not. I would never use it on the inside. Anyway hope that helps?

The link I gave at the top covers my process for applying an Epoxy or poly finish. Click on it at your own risk!!! Ye have been warned..

Flame suit on.

hey JOL, you've already given us plenty of criticism, now give us constructive criticism. Like I tell my teenage son who is so hungry for political activism, pointing out problems without offering soloutions is just more trouble making. What we've asked you a few times is to tell us what recepie gives you the hardness to your finishes that you claim. If you keep this secret because you developed it and you want to protect your process you should realize that we are not threats to your didgeridoo empire. Probably only pvc crafters have been more prolific than you, and they're not your competition either.
Your first lesson here to didgecrafters seems a bit strange. Can anyone think of a crafter known for high quality agave that splits their canes? I'm not an agave crafter, but if you want info on others processes you can simply ask here and the generosity of the tribal spirit shall overfill your cup.

I've been using envirotex only recently, prior to that i used the TAP plastic resin that apparently makes people crap their pants. Unless you plan on making a large number of didges and storing them in the same room that you sleep in, try the both out. We've got plastic everywhere, if its all gonna kill you at least one product made with it will entertain you for years....
I've tried a few yucca sticks using beeswax, candle wax , sawdust, quartz and linseed oil. It got funky, muddy and certainly wasn't very durable. threw in a little tea tree oil and lavender to mask it up but the funk still prevailed after a while. They more unforgiving to heat which given enough exposure make any fatty oil go rancid, you may not smell it over the tea tree for a while but it will happen. I've seen pix of JOL's stix and i'm pretty intrigued by their appearance and i hope he brings one to the fest in August, i'd really like to see how durable his mixture is as well as the sound.
for myself, i've found epoxy to provide the best of both worlds and i'm able to take my didge to the beach and still use it as a walking stick, while playing to the ocean or climbing up a trail without worrying that my didge is going to splinter if i bang it against something, hell i've rolled down hills with one strapped to myself without a crack.
BTW, titebond is great for putting a split cane together but it doesn't mean the whole thing is stronger than before, it will just split on either side of the seam inside of at the seam.

well in response to the curius didge maker, i find that mixing waterproof wood glue (i use a nontoxic elmer glue no its not vegan but at least its not dinosaur)and a rigid substance. ive had great luck with powdered clay, the dust that I recover from sanding, and charcoal. the best way to apply it is with a rag on a stick if it starts to set up too quickly add more glue and for god sakes mix it well. you can swab it through the didge with a rag on a stick, just pretend your a monkey harvesting termites thats what I do, i find it makes the work go faster. a single coat spread eavenly throughout the inside of your yucca or agave will completely seal it. allow it to dry for at least three days before sanding. I find that sometimes the tiniest cracks can still make there way through. if you desire another coat go for it you can also get any cracks from the outside with multiple layers of your mixtur w/ water to thin it. wipe it withe a rag and gently sand it. warning with powdered clay do not add water because it seens to activate it and make it clumpy and brittleinstead just use more glue. too be honest with you ive never had a didge that i built this way fail the outside may be more subceptible to scratches and what have you but the natural beauty of an instrument that has been crafted with the utmost care makes it worth doing right. i find that poly urethanes and such often times leave a milky gloss that conciels the woods natural finish. not to mention the enviromental impact of the refinement of such things. also polyurethane can crack and chip, yellowing and spiderweb cracking will happen eventually even with non-yellowing finishes .the proper penetrating oils suh as pinion pine oil will penetrate and preserve wood grain as well as add deapth to the natural wood patern . any more questions or if I left something out just say so.

cha cha cha!