Birth of a Doundounba

I started a blog a while back and had no time to invest in it, nor did I have a solid direction of what I wanted to accomplish with it. I had no worthy posts except for the following, so I am resurrecting this info for my new blog! I’m guessing the material is a few years old. This drum was built before I had a shop to work in! There was a mess of tools in the kitchen, and my old table saw was pulled from under the house whenever I wanted to work…. I’ve come a long way since this post! (more reason for me jumping into blogging… so I can follow my own progress and so interested people can stay in touch with what I’m doing…Enjoy!

Edit: Once I got this copied over and photos added and edited, I realized it was missing some key information… so I’ve edited this post a bit from the original one back in the blogspot days… 🙂
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I recently got an order for a purple heart doundounba. I love building these and they always turn out nice. I thought I’d document the process for those that are interested.

First thing is that I have to get the rough lumber. A lot of places sell purple heart wood as craft wood, already smooth, square, and even. Not for me. I want the rough stuff. I like the process of planing down the wood, squaring it up and getting each stave/slat just right. It gives me more control over the process. So I got my rough purple heart lumber and started cutting to length when it dawned on me that the process might be of interest to others, so I grabbed my camera.

If I have a really wide piece, I’ll rip it on the table saw first, then I cut the boards to length. It seems to be easier and that I make less cuts when I cut the wood to length before I rip it to the width.

Bellow are all of my purple heart staves for the doundounba. They have been cut to length and have all been ripped to the exact width I need for a 17″ doundounba. I’ve got high hopes for this drum. These staves are really tight grained and some have a nice swirl that will really pop on the final drum. This is the point where I start getting really excited! I’m building a purple heart sangban along with this doundounba… so you can see the smaller staves for that at the end of the table.

The next step once I’m happy with the roughed staves is to plane them to thickness.? Depending on the sound of the drum and the size of the drum I will plane to different thickness.? Remember that a thinner shell body will vibrate easier giving you a lower resonance in the shell, where a thicker shell thickness will give more projection and brighter sound.? Once they are square and planed to thickness I put a bevel angle on the staves. The angle to the edge of the staves is what makes them join up perfect to make a round barrel. This angle is crucial! Just a TINY bit off here, and your drum will be out of round, not glue up properly or be week at the joints… the only way to fix it is to start over, or build a smaller drum by re-cutting the angles. The angle of the bevel is determined by the number of staves you have… really simple. Cutting these for an ashiko is a whole other story as there are far more complicated mathematics that go into those angles. So there are 360 degrees in a circle. If you have 18 staves each with 2 sides that makes 36 edges to be glued up. Well these angles have to match up to a circle (360 degrees) so you simply make the angle 10 degrees on each side. (360 divided by 36). The width of the stave will determine how large the diameter of the drum will be. This calculation is a little more tricky and takes into account the number of staves… here you go…

2*(Diameter/COSINE(PIE/Number of Staves)/2)*SINE(PIE/Number of Staves)

Do I do this math for every drum…. HECK NO!! I’ve put all my formulas in a top secret excel document that I can just plug in what size drum I want.. and whaa-lah!! I have my answers!

So for this doundounba my diameter is 17″ my number of staves is 22, so each stave will be just under 2.5 inches. I never like my staves to be too fat. A stave much larger than 2.5 will be very hard to make round.. too much work. So …add more staves, lessen the angle and with width of each to make the drum more round. The more staves, the more important you get that angle just right!! With 18 staves you have 36 edges (angles) that means any bit your angle is off on the saw is multiplied by 36! This tool works like a charm! (however I now use a digital angle finder as it gives me the angle much faster and I don’t have to squint to read the numbers)

You can make this cut on a table saw, if you have a nice blade. I find the jointer to be much more accurate and give a very smooth face which helps make the final drum solid. I love this machine. It is the heart of the staved drums that I build. I keep this baby tuned up and inside. One little booboo on setting the fence angle or with the settings of the blades, and I’ve got to get back to the drawing board. I could still use the staves for a smaller drum… but I like to make sure I build the drum that has been purchased…. and build it right. Keeping the blades sharp and nick free are essential to having a good solid glue up.

Here is the stave after I have ran it through the jointer at the specific angle. Just 22 more to run through and I’ll be ready to glue up this doundounba!

While running these staves through I check very carefully to make sure the angles are smooth, level and most of all that the staves stay consistent… each has to be exactly the same for math we did above to be effective.? I keep the first one I run through, and make sure all the other staves are the same width. Having a perfect angle doesn’t do very good if the width of the staves is different. Slight warping in the wood can cause dips in the bevel, so I might have to go over a piece more than the others… this is why I usually have 4 or so extra staves per drum I build.? Another issue that hits every once in a while is chip out near the end of the stave. Running it through slower helps with this, but again, it’s good to have a few extra just in-case they don’t all turn out perfect. And if they do, you’ve got some extra wood for your next drum. Because, well… there will be anther! 🙂

After all my staves are just perfect I lay them flat on an even surface and determine which wood will look good next to each other. Sometimes the grain can match up so that a certain pair of staves just look great together…. so I play around with this for a bit.

 

 

After I get them how I want them, I flip them all over and start gluing up the staves… once they’re all glued I stand them up and use a ratchet clamp – I now use stainless steel worm gear clamps as I’ve found it distributes the pressure more evenly – to pull all the staves in tight. I think I’ve used a bit too much glue on the sangban here… no worries though, I sand the shell down a lot, so in this case it’s better to have a bit too much than not enough.

 

 

Here you see the glued up dununs (the doundounba and it’s smaller brother the sangban). I let the glue dry for at least 24 hours. The glue I use is stronger that the fibers in the wood. It holds 80 percent of it’s strength up to 1/64 of a gap. So a tiny bit of play is acceptable, but the better your angles match up the stronger and more solid the shell will be. 1/64 is pretty small margin of error… so check your angles before you glue up!

The other photo shows the dununs all cleaned up, rough sanded and ready to be shaped and have a bearing edge slapped on.

For the bearing edge I use these:

These raps are great for shaping the bearing edge. They remove a lot more wood that a sander and really let you fine tune the shape. It takes a lot of rasping to get a good bearing edge… but it pays off spending some time on the edge as your sound will be much more warm and pure…UPDATE… I actually now use a different method for cutting my bearing edges. It’s much faster and gives me more accurate and consistent results. The rasps work great, but I’ve migrated to a router table with a few custom-made bits that give me the profile I want.

After sanding down the shell and shaping the bearing edge I coat the shell with oil. Sometimes BLO (Boiled Linseed Oil) and sometimes Danish Oil or Tung oil. It just depends on what else I plan on doing with the shell. I use Danish oil if I just want a few coats to protect the wood and darken it up. I use the BLO if I am going to put a top coat of poly-something. I usually like the wood in it’s most natural state, but sometimes the polyurethane look is nice. Depends on my mood, what the customer wants and what woods I’m using.

Below is the completed doundouba shell, with a few coats of Danish Oil. I added a sound hole (I do those depending on the sound the customer is after). The hole adds a tad of attack and volume. If you like the dununs sounding warmer, leave off the hole.

Once the shell is complete I move on to the heading process.?? I roll and weld my own rings out of 1/4″ cold rolled steel rods.? I used to buy them, but the fit was never as perfect as I wanted and I didn’t like waiting for shipping. Though the initial investment for a welder and the ring rolling equipment was high, it’s paid for itself many times over.? If you are attempting to build your own shells, I sell drum rings at any diameter.

I got behind on this project a bit and needed to hurry up with the heading process, so I didn’t get any photos of mounting the cowhide on the doundounba.? Heading the dununs is similar to heading a djembe or ashiko, but there are two sides so you have to make sure the rings stay level on each side or the drum will end up looking lopsided.? It takes patience and slow tuning, but well worth the time for level rings.

Once the hide is dry I do a final tune, oil the skin with some shea butter and/or coconut oil and play the heck out of it! :)? This gives it a bit of a break-in so it gets to the customer sounding close to the final sound.? It takes a good 2 weeks to a month for the cowhide to really break in and start sounding warm and natural.

The finished Doundounba and Sangban…