How to Build a Curly Box-didge, and How Not To

BACKGROUND
Didgeridoos are intriguing and fascinating instruments. They make a wide range of sounds, and in the hands of an expert they almost ‘speak’ to you. There’s also a broad range of the types of music played on didges, from the ultra traditional, to mind-boggling rock, and everything in-between.  If you don’t believe me you only have to look at YouTube to find a massive amount of wide-ranging didge virtuosity.  It’s wonderful; it’s incredible.  And I want to do it too!

I am a beginner didge player, being encouraged and guided by the great guys at Banbury Didgeridoo Club, in central England.  These guys are awesome players, but thankfully they are also patient teachers, and my stumbling and bumbling doesn’t put them off their stride at all.

As well as learning to play the didge, I also have a fascination with making them  -  I guess whenever I find a subject interesting I ask myself: “I wonder how they do that, I wonder if that’s difficult to make?”  This attitude has led me down many a rat-hole or dead-end, but it’s also rewarded my curiosity by occasionally turning up something I can build and enjoy constructing.

The very best didges are those from trees which have had the branches hollowed out by termites eating the dead internal material, leaving essentially a tapered, hollow wooden ‘pipe.’ I believe it is generally accepted that some number of thousands of years ago, a hollow branch was found and somehow an aboriginal chap decided to blow down it to see what happened. I guess it’s possible that a wind was blowing, and the branch was making a noise all on it’s own, and the aboriginal chap decided he’d have a go at making the noise himself. I don’t know, it seems like a nice story, and maybe it happened some way like that.

These days wooden didges which have not been termite hollowed tend to be made by the process of splitting the branch lengthways, usually with a band saw, then hollowing both halves, and then gluing the halves back together again.  I make it sound real easy  -  let me tell you, it isn’t!  But that is not the subject of this ‘ible.

Even more recently, there have been other developments in the world of didge making, with plastic didges (which are really incredible, if you haven’t heard one I recommend you check it out.)  There are also didges, which are carved into incredible sinuous curved shapes, even spiral ones! – which often cost somewhere to the North of $300, and there are also things called ‘box’ didges which really look just like that, a rectangular box with an airway which travels up and down the box 2-3 times, depending on the note you want to achieve.  Box didges are great in that they compress a 7-foot didge into a compact and easy transportable package. The only problem is that (in my opinion,) they look awful!  In my view, if you’re going to try to make an instrument, which should sound lovely, it should look nice too.

As much as I enjoyed helping my friend Simon to make a traditional straight(ish) didge, I decided I was looking for something more compact, more easy to transport and heft about. I decided that although I already have a straight didge, the one I wanted to make had to be something different.

So, I decided I wanted to experiment with making a ‘box’ didge, but I didn’t want just a boring overgrown cigar box, I wanted something much more like the carved, sinuous models.  The only trouble with that plan is that I can’t carve, and I couldn’t afford to buy a big lump of exotic timber, and then make a big mess of it.  I also have a very limited array of power tools available.

Now I needed to find a methodology of construction, which would allow the cutting of an air channel out of a lump of material, then cutting the outside shape to reveal the final product.  I could not afford a large, thick piece of timber, even to cut with a jigsaw, so it quickly became obvious that I was going to have to make up the large lump of material from smaller thinner sheets, as a form of lamination.  At this point I quickly decided upon MDF, because it’s cheap, easy to cut, and easy to sand for a smooth finish.  The downsides (discussed later,) were completely overlooked (not recognised) at this time, and plywood was ignored due to cost constraints. This issue would come back to haunt me in time  -  so, beware of making snap decisions, and try to think out ALL the options fully before setting out on a project.

The methodology chosen for this project was mostly driven by my lack of sophisticated tools.  I was pushed down the route of cutting a fundamentally 2D airway, because I pretty much only had a jigsaw to work with.  How it would have been different if I had access to tools like a router ? -  it would have made all the difference in the world.

Initially I spent a lot of time evaluating plans drawn in 2D in Adobe Illustrator.  Eventually, after a number of false starts, I decided upon a design which I felt offered the right blend of airway shape, and outside form.  It was going to be fairly sinuous, and if the build went to plan I would have a nicely shaped didge.  I set off on my voyage of discovery, in the making of what I call, my Hobbit(© JRR Tolkien) Didgeridoo.  If Hobbits played didges, they’d play ones like this.

In this ‘ible, I will make the assumption that you know nothing about how to cut something out with a jigsaw.  OK, that may seem insulting to most or even all of you, and I do apologise for that, but without starting at first principles, I reckon there will be people who wonder how I got from place A, to place B.  I hope everyone is OK with that.  It also will point out with painful clarity, just how limiting this methodology would eventually prove to be!

Materials and tools
I bought a slab of 11mm MDF (medium density fibreboard) which was to be cut into 4 strips about 300mm wide, and 500mm long.
I bought a slab of 7mm MDF, which was cut into the same size slabs, though I would only be using 2 of them.
I used a good cordless drill
I have a very cheap (£21) jigsaw – which proved very adequate
Clamps are an imperative – I used between 2 and 8, for various tasks
Sanding blocks (those foam ones covered in sandpaper, or aluminium oxide paper)
You’ll need plenty of PVA woodglue
A hole-cutter is useful, but you could alternatively use a large diameter spade bit
A sharp knife is useful
A vinyl cutter is very handy, but if you are good at drawing, you can just do that
Transfer tape for the vinyl

Step 1:

Method
To get the ball rolling, I drew the design for the airways in the didge, on my Mac. I made the design 100% size, as I was going to cut it out on my little vinyl cutter.

It took many attempts at drawing this design, and in fact this example is the second one I committed to beginning manufacture. My first attempt was much narrower than this design, and although I made the vinyl pattern, and cut out the wood, (which was a nice plank of mahogany I have had lying around for years,) it eventually became obvious that the air channel was just way too narrow for the project to work, so it was abandoned.

Eventually after numerous experimental shapes, I concluded that I needed to go a lot wider than earlier plans, which would mean that I would have to cut the vinyl design out in two halves, because although my cutter can go to 600mm length (which is fine,) it can only do 200mm wide, which I concluded was way too tight for this project.

I finally arrived at a shape I thought would work – in which the airway got wider as it progressed from mouthpiece to outlet.  If I had stopped and thought things through at this point, I might have decided to make the part of the airway nearest the mouthpiece a little narrower, but we’ll cover that in the conclusions.

In preparation for cutting, I glued all 4 of the sheets of 11mm MDF together, and clamped them tightly until they dried. This formed the large lump of material I was looking for.  This great lump of MDF was to become the internal part of the didge, and was going to need hollowing out to make the airway.

Step 2:

I applied the vinyl design to the MDF, using transfer tape (which is low-tack tape in a very wide format, applying adhesive vinyl to a substrate without transfer tape is like trying to knit without needles, just forget it!)   The transfer tape lifts the vinyl off its backing paper, and then you place the tape and vinyl on the work-piece and rub it down firmly. The transfer tape (being low tack,) can now be unpeeled from the work-piece, leaving behind the vinyl.  In my case I had to do this twice to put together the design from the two halves.

At this stage you can see the design  -  the black vinyl represents the material which is going to be left behind after cutting, and all the rest of the material will be cut away.  You can see at this stage that there are 2 ‘voids’ which are not in the airway channel, and really serve no purpose, (though the larger one was conceptually intended to be a carry handle.)  As I progressed through the project, and some of the problems started to become glaringly apparent, I decided to concentrate on making the thing as simple as possible. I concluded I would get to the stage of being able to evaluate the instrument as to it’s playability, and not worry too much about it’s final form.

As mentioned, you obviously don’t need a vinyl cutter for this project; you could just as easily (I suppose, if you are good with a pencil) draw your design straight onto the block of material.  Well, if you can that’s great, for me, the vinyl way is easier.  I suppose tracing would achieve the same result.  Whichever way you go, I can only say that at least doing the design iterations on the computer makes it easier to adjust and keep tinkering with the shapes.

You will spot instantly that there is a black piece across the mouthpiece of the didge, as well as another one across the airway outlet. These are obviously not intended to be there at the end of the project, they are merely temporary devices intended to make the shape stable. This is because if I didn’t leave these ‘bridge’ pieces in until later in the process I would end up with two separate parts left after cutting, and these would be more difficult to handle and more fragile,  as opposed to working with one piece until later in the build.

Step 3:

Now the design is on the material, you need to drill some holes (large enough to accept your jigsaw blade,) in the corners and tighter curves of the shape to be cut out.  The holes serve 2 purposes; firstly, a jigsaw can cut straight into a piece of material if you are starting a cut at the edge of the material, but obviously a jigsaw can’t start a cut inside the material  -  it can’t get it’s blade through the solid stuff to get going.  Secondly, these holes are useful because although jigsaws can cut curves, they can’t cut incredibly tight curves, and you’re going to have to cut tight curves from both directions to get a good finish.

Step 4:

This picture shows the start of the cutting of the inside of the enclosed interior shape. It doesn’t matter where you start, just make sure the piece is well clamped down, and make sure you’re not going to cut your work-piece, and then carry on cutting through the table beneath  -  doing that makes you very unpopular.

As mentioned before, a jigsaw can cut curves but not curves which are incredibly tight. In a situation where some curves are too tight to get round, you have to cut the pieces of waste material in sections, to allow you to start the blade again in the right direction. In this picture I have cut up the left part of the shape, but the right side was going to be impossible, so I cut across the waste section to allow the first piece to drop out, and to give me 2 more staring points where the blade direction would be on a more gentle curve.  You can see the piece, which has been removed.

Step 5:

This picture shows the didge with about half the internal waste removed.

Step 6:

This picture shows all the internal waste removed. You can see I had to cut it out in numerous sections in order to get the jigsaw to cope with the curves.

At this point, the void right in the middle of the design, which I intended to remove, was left in. I decided there was no major benefit to having the void going right though the instrument, as it was too small to be of practical use, and it would involve too much work to cut and smooth.  You must never be worried about changing ideas in a prototype  -  after all, that’s what prototyping is for  -  if something doesn’t seem to make sense after you’ve started the build, just change it and move on. Don’t get hung up on details!

Step 7:

The thing I did next was to glue one side of the thin 7mm MDF onto the didge, and then cut round the outside of the design to get to this point.

Here you can see the jigsaw saw line, which needs to be close to the design pattern, to reduce the amount of sanding later, but not so close that you might cut into the design and thereby make certain areas smaller than you intended.

Step 8:

Here’s the first half of the outside portion of the waste material.

Step 9:

This is the other half.  Now that I have the didge internal shape and one side plate glued together, I applied a couple of coats of varnish inside the airway, to reduce problems of moisture build-up.  Didges get warm and moist inside from the blowing of hot breath down them. Most of them are protected somehow with a membrane of varnish, PVA or oil.

Step 10:

I realised that this was going to be an especially big problem with MDF, which is (relatively) an open grain and porous structure material, and it was going to be important to coat the inside to protect against moisture absorption, but also to reduce the amount of sound-deadening made because the material is so soft, and also to seal against dust being shed by the material.  I am not so experienced with MDF, in fact this is the first time I’ve used the stuff, and I have to say the amount of dust, and the relatively high porosity came as a pretty big surprise to me.  I suppose I expected something which would be as compacted inside as it appears to be when you inspect it’s outside surface. This was an error, which would grow in magnitude as I continued with the project.

At this point in proceedings, I must say I did start to wonder about the wisdom of using MDF, rather than plywood  -  but I felt I had reached a point of no return, (and in any case the money was already spent!) and as this was only to be experimental  -  a prototype to test the shape of the airway, I made the decision to press on.  I am very glad I did so.

After applying the varnish inside the didge shell, and also to the second outside plate, I applied a generous helping of glue to the didge shape, and glued the second outer sheet onto the didge body.

You can see in this picture that I have cut out the ‘bridge’ part of the design, which I had left across the airway outlet.  Now that one of the side panels is glued onto the didge body, it is safe to get rid of the bridging piece. I left the bridge at the mouthpiece, and used a hole-cutter to make the mouthpiece, through the bridging piece.

After allowing the glue to ‘go off’ I cut out the second side the following day.  Here’s the didge showing where the side panels are both attached, some sanding has been done to the edges of the piece on the right as you look at the piece, though the left side is still rough as cut by the jigsaw.

Step 11:

This picture shows the didge from the mouthpiece end. The second pic shows the bell or sound emitting end. I have put 3-4 coats of varnish on the mouthpiece and inside the mouthpiece hole.  This made a huge difference in terms of comfort  -  blowing onto MDF is both deeply unpleasant, but may also be dangerous as the fibrous nature of the stuff is a possible inhalation problem.

I decided at this stage that although this should be seen as a ‘work in progress’ I would actually stop any further work on the piece.  It had been my intention at the outset to make a sinuous and slinky didge, with well smooth and sanded curves, and a nice paint and varnish finish.  However, the obvious failings in the design (we’ll come to that in a while) and the obvious problems with MDF convinced me to expend no further time or money on the project.

I went for a cheap material  -  one which would be easy to cut with my jigsaw, and easy to sand and finish. I looked at the ease of construction and didn’t look deeply enough into the properties of the material itself. I learned a massive lesson. 

OK, this was an experiment, a prototype, intended to evaluate an airway shape, and as far as that is concerned it’s a partial success.  But the problems of the MDF were severe enough to make me stop at the point where I could get the playability tested, without embellishing the appearance of the didge.  I did sand all the outside edges, just to get to an almost-finished state.

Step 12:

Conclusions.
I took the didge to a monthly meeting with my chums at the Banbury Didgeridoo Club, and most of the guys actually played the didge.  It was not perfect, that’s for sure, and I know what the deficiencies are, but it played, it really did play, and it wasn’t a million miles form being a ‘proper instrument.’

I was elated, really uplifted and encouraged.  I feel very strongly that I could build a curly-whirly didge, with musical properties to compare well with a traditional straight didge. What I need to do, though, is use a material which is a darn site more stable than MDF. I also need to refine the shape of the airway at the end closest to the mouthpiece.

There are further fundamental changes I would make to the design for the next version.

Imagine if you will  -  go back to the very early part of my story, and consider the design  -  there’s a huge mistake just sitting lurking there, which I just didn’t take into consideration.  I didn’t realise the limitations of making the airway in this methodology.

The difficulty in playing the didge, and the property which made it almost successful but not quite, is that although the airway does get bigger in the width and length dimensions, it remains constant in thickness, and therefore, right at the mouthpiece, and for about the first half of it’s sinuous length, it is way too deep in thickness.   This makes for too low a ‘back-pressure,’ which is an important element in didgeridoos, being responsible for the establishment of a good ‘standing wave’ and pleasing frequency generation.

Although the guys at the didge club really did make some great sounds, they all said it was hard to achieve, and the lack of back-pressure was a big problem.

Step 13:

So  -  what should I have done?  Easy.   I really should have cut each laminate separately instead of gluing 4 layers together. That way I could have made the airway near the mouthpiece much narrower, and have achieved a much more gradually growing airway shape.  I think this would vastly help the backpressure problem.

Mainly, I also should have spent more money and made this out of plywood.  MDF was a mistake  -  and I would urge you to not go anywhere near the stuff if you plan on doing anything involving breathing near it.  Seriously, this stuff also has glues in it, which are probably not good for you either.  I really, really should have thought this through more, before setting out.

But hey!  That’s what experimenting, and making prototypes is all about. I made something, which is very nearly perfect, and I am determined to make one which really will work.

Step 14:

What if I had better tools?
Well, certainly if I had access to a router, I could have cut the airway in a much rounder shape, and made the shape uniformly smaller diameter at the mouthpiece end, and grow in diameter smoothly over the length of the airway.  This would also allow the building of the didge using just 2 halves, and cutting just 2 airway halves with the router.

My Very Final thoughts
OK  -  I can hear a number of you saying that this isn’t an ‘ible about how to make a curly didgeridoo  -  but a story about how NOT to make one.

Actually, I really hope that most of you will see it as a bit of both. I have described how I made one with a jigsaw, which I wouldn’t recommend. However, I also suggest how to make one with a router. I also come clean and explain just how easy it is to end up with a ‘near miss’ rather than a complete success, either through using the wrong materials, or not considering some design nuance early enough in the project.  It’s a genuine lesson in what can go great, but what can also turn into banana skins when embarking on any project.

One thing I would also stress is that if you feel you may have a dud on you hands, at least get to a point where you can validate some of your design. Of course, if your dud is going to work out dangerous, let it go, but if you can, get to a checkpoint. Validate your views – with other opinions if possible, and only then commit the thing to the dud pile if you are sure.  In my case I stopped working before committing energy and money on the cosmetics of the didge. I had reached a point where the playability could be determined.  Even though I had lost faith in the MDF materials, I was committed to at least get to the point of it being ‘an instrument,’ so I could properly evaluate my airway design.  I now know the design is very very close to ideal, and I also know how to improve it.

When I get the design refined, and have access to a router, I will build one of these in plywood or chipboard, and let you know how I get on.

Thanks