Advice and questions on making and fixing instruments
#38664
Hello!

I am in the process of doing research for a sustainability project that my boyfriend has founded, and I am co-founding. He and his crew are master craftsmen of Djembe & Kpalongo drums in Ghana, and he is looking for a way to use the wood chips & saw dust from carving, and form them into drums (to try to lessen the impact on the local environment as well as recycle.) The biggest thing is the adhesive, and figuring out what will bond the wood shavings as well as be durable to stand up to the vigorous playing. My dad suggested polyresin, but I'm not sure what would be easy for my boyfriend to find in his local area.
If we can find a surefire way to do this, we have a feeling it will be the first step in many to come...but I wanted to pose this question to you folks and see what you suggest.

Thank you so much for your input as well as your time!
#38686
It's great that you and your boyfriend have sustainability in mind. I'm just not sure how practical the idea of making drums out of carving byproducts is. I suppose it depends on the type of drums you want to make.

It seems to me that if you want to make djembe shells, for example, you might have to use more adhesive than byproducts, because djembe shell must be so sturdy. I do not know this for a fact because I've never tried what you propose. It's just what I imagine.

I do hope you find a way to make your idea work and that you'll share with us the results of your efforts, regardless of the outcome.

On a side note, would you please share pictures/videos/links of the djembes your boyfriend makes? I've seen many djembes from Ghana but not single one of them was made by a master craftsman.
#38716
It should be possible, but I'm not sure whether it'll be economically feasible. (Similar things have been done; search for "Stone Djembe" in this forum.)

Resin sounds like the way to go. You'd end up with something similar to craft wood. It might sound just as bad as fibreglass djembes though. There is no way to find out without trying.

Michi.
#38782
First of all, I want to commend you and your Boyfriend for the inspiration for this project.

I've explored this myself, I even made a prototype drumshell from sawdust, and I can share a few realizations. I list a few binders below.
Experimenting will be necessary. Testing various recipes and methods etc. This can be fun, if you see it as a challenge.

I used sawdust, water and acacia gum. I made a kind of dough, or clay, out of it, and shaped it onto a cylindrical mould.
It started sagging down before it dried, so I wrapped it in cheesecloth to keep it in shape. Not very elegant, but it worked. The cheesecloth is now part of the exterior, and it looks cool with the sawdust, a kind of natural art.

Very little gum powder was required, diluted with lots of water. The trick is not to overwet the sawdust. Just enough to make it stick together and form a "dough", but not so much that it sags while drying. I added too much, lesson learned. It would help to add fibers to give it strength, like hemp, jute, etc. Anything really, even strips of cloth, or long flax-like grasses like sawgrass, or bark from canes, weeds etc. The prototype is very strong, but on a full sized djembe, if it gets dropped, I'm afraid sawdust doesn't have long enough fibers to prevent a piece breaking off the foot or stem. It won't crack though, which is one advantage over wood.

Here's a few ideas for binders, I can provide more if required.

A) Protein Resin: Essentially it's Protein powder + Strong Alkali/base + water. Very strong. Protein isn't cheap though.
B) Acacia Gum aka Gum Arabic: Not cheap either, but you can dilute it a lot and it still works, and it might be more available locally, since it comes from Africa. I think mine came from Senegal)
C)Tannins. I was able to make a composite with hemp fibers and tannin from treebark. Too much and it becomes soft, the key is to add enough to make it stick, but not so much that it's soft. Abundant, cheap, but requires experimenting.
D) Alkali. Simply mix water with alkali and sawdust and allow to dry. Might not be strong enough, but it's the basic principal behind paper I believe. (Alkali dissolves the surface cellulose, so as it dries, it should form a bond)

Details:
A: "Soy/Protein Resin": You can make a glue from any protein powder (soy, gluten, etc.) combined with a strong Alkali such as Lye(Sodium Hydroxide, NaOH), or Potash (Potassium Hydroxide, KOH). Potash is easier to obtain, because you can make it from wood ashes. Simply dissolve ashes in water, filter, and allow to dry. I buy it from a soap making supply company.
This is how Soy resin is made, and it is a very hard, strong substance. A small amount, dissolved in water, mixed with sawdust, and allowed to dry, would form a good bond. The Alkali will partially dissolve the cellulose in the sawdust, and make it bond, and also the water will cause the cellulose to bond naturally via Hydrolysis, which is how paper is made.
You might even be able to use Alkali and water without protein, experimenting is recommended.
But be careful! Alkali can burn skin, and spatter when mixed with water, so read the instructions, and use Ph strips to measure the alkalinity (cheap, available from home brewing supplies)

B: Acacia Gum, or Gum Arabic. This is a sap from an Acacia species. It's renewable, but not the cheapest option. However, only a small amount is needed, so it can be very dilute, to make a strong composite with sawdust.

C: Tannins (natural, plant based chemical) This is perhaps the cheapest option, as you can literally make it from waste materials, such as bark, leaves, etc, by soaking in water, or boiling. It's basically the same idea as dying cloth, except you are dying the sawdust, and as it dries, the dye helps the sawdust stick together. You may find certain chemicals make it work better, like citric acid, or acetic acid (vinegar), or even minerals, like"tea" made from metal-rich clay(red clay, or dark mud), there's chemistry involved. I learned about this from Bogolanfini, the mudcloth technique, and it uses plant tannins, mud, and binds to cellulose (fabric).

D: Alkali is basically explained above. Use caution. (always add alkali to water, not water to alkali, or it can spatter. Always wear eye protection and gloves. Never get it wet or can "explode", causing caustic burns) Could be very useful if it works, since you can make it from the sawdust by burning it. To burn sawdust, first wet it, form into logs or bricks, pressing firmly, allow to dry, (hydrolysis should make the cellulose stick to itself) then burn as usual in a fireplace.

Also about Water Based vs Epoxy:
Water based binders work best because as the water dries (evaporates) it leaves behind air gaps, which means the final product doesn't have to be so heavy. Composites made from epoxy resin and chip materials tend to be heavier than the Djembe hardwoods. Also they are not environmentally friendly, so defeats the purpose. Although if plant resins are used, it can be clean. In this case, plant sap (the sticky kind which leaves resin) can be mixed with sawdust and then allowed to dry. Heat will be needed to speed the drying process.

It can also help to make the composite two stages.
First, binding the sawdust or fibers with a water based binder.
Then when it's dry, applying a water-resistant chemical, like shea butter or oil, beeswax, or tree resin.
This way, you get the ease of working with water-based chemicals, and the added strength from the addition of water repellant chemicals. Again, experimenting is required to find the right combination.
#38856
Thank you so much for your input :) I think the biggest thing that he will have to do is experiment until we find the correct ratio...and then go from there.

If you have access to facebook, please feel free to check out his page, https://www.facebook.com/kofi.atentenben he posts photos of the completed drums, textiles and jewelry that he and his crew have for sale.
#38858
Thank you so much!! It was my boyfriend who originally came up with the idea...he was looking around his shop and the idea struck him, since its expensive & harsh on the environment to get wood from the bush. The hardest part is going to be finding the correct bonding agent, but I really hope his project will take off once we find the proper agent. This project means a lot to him and his crew, and I would love to see it succeed. Any ideas, suggestions, pointers or other commentary would be vastly appreciated.
#38863
Maybe the guy could take up modeling instead. Joke, just checked his facebook and he is a handsome guy.

It doesn't sound very realistic to be shipping down glues to Ghana to make chipboard drums. But they may have sources to china from there. I didn't exactly think you'd be well stocked with resins down there.

I would think it is so cheap for wood down there that there is no way they resin can be cheaper than wood. If you want to make animal glue how many innocent rabbits have to die to make that glue. lol. OR like how many kilos of materials goes into these glues or resins?

Like in the Gambia you could buy wood for a djembe for 5-10 euros, 10 years ago (obviously that was a while ago, has wood drastically gone up in price?. How are you gonna get resin for that cheap? impossible.

Plus mold ed drums mean all the drums are the same. You end up loosing the uniqueness that makes these drums special. Plus the sound may be crap as was mentioned up stream. There is also structural considerations like can this blend support the power of high tuned skin and rings?

People want to believe it is possible to do a project like this but i can't see how sustainability has anything to do with it. You expecting to make a business making drums from chip board wood and mai ingredient is a non local heavy product.

You could buy land and grow a bio diverse garden with trees for future djembes and food to make money and feed people then fine lets call it sustainable.

A way to not waist wood would be to modernize the drum workshop so all that wood is not chipped off and is rather cut and can be used on other projects. Look at some one like rhythym house drums making stave drums. I wouldn't think it easy to get to his standard though. Might take a few years plus thousands in tools.
#38903
@ Asahelt2/OP and others interested, see below for a few photos of my prototype. I'm sure you could do better, I added too much liquid, and the dough became a bit too wet, but you get the idea.

@ The kid:
But you don't need much binder to bond the sawdust together. It's a fraction of the total weight, perhaps 1-2% would be sufficient to bind it, with the right technique. Also labor is a cost, and shaping dust-dough is way easier than carving.
(plus it uses waste material so it's cost efficient) And what I used is a locally available natural renewable resource.

I used very dilute Gum Arabic (dried Acacia sap powder from Senegal, Acacias grow all over Africa), and it held together remarkably well despite being diluted with lots of water. I could stand on the side of my shell and it wouldn't break. When mixed with water, it creates a large volume of liquid glue. When dry, the water is gone and the gum forms a very thin layer between the particles of wood dust. There is also airspace, which makes the shell lighter than one made from epoxy resin, which tends to fill every crevice. This airspace can be decreased by applying pressure once the shell begins to dry but before it's fully dry, to make it denser, but my result was dense enough to make a Djembe. Feels like Iroko, harder than Tweneboa. But it did come from mixed hardwood sawdust.
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#38905
Nice one Bata,

Thats really cool.

I'm pretty interested in this technique i just don't really imagine making djembes out of it, unless a composite is created to emulate the hardness of wood.

But dunduns sang or kenkeni would be moire plausaable.

Looking at a calabash i see an extremely hard outer surface and foamy inner material. This is the root material for many african instruments due to it's acoustic properties, maybe a precursor to a djembe style drum. To me this hardness is necessary to create the sound and the foam is good at diffusing the sound and making it sound good. Just an idea really.

So i would say the best way to work this idea would be to try to emulate the composite structure of calabash and try to use that as the material for the drums rather than trying to emulate wood.
#38910
@ The Kid: Thanks, it was quick and easy to do. As far as material strength, it's actually surprisingly hard. When I knock on the side with a wooden drum mallet, it sounds kind of "nutty" if that makes sense, and it's not dentable with a thumbnail. It looks mushier than it is. I think it would be more obvious if I sanded and finished it, so it was shiny and smooth. The sawdust was all hardwoods from a local mill, some exotic, some domestic.

But I agree with you, it's not going to sound like whole wood, it's a different material, because the fibers are every which way, and there are random air spaces where the water has evaporated, and the dried gum is connecting the fibers.

Still, I think it could sound surprisingly good, and there's only one way to find out. And if it might make a decent option for people who can't afford one otherwise, it seems worth trying.

What you described with the Gourd (hard outside, soft inside) is exactly what I think makes my bamboo flutes sound so buttery. The higher frequencies are smoothed out, so it sounds mellowed and less "sharp". Works well for jazz and native american style. Makes me thing that might be part of why Koras/Ngonis sound so good.
#38914
What are the dimensions of the piece that you made? With out actually putting a large enough piece and testing it with a skin and ring rig , you may not be so sure it was 'was dense enough to make a Djembe'. Maybe so, again i'd say that is something to be proved. Are you saying it is dense enough but you haven't built the scale model and structurally you'll see how the piece holds up under pressure? I guess density versus structural integrity are different things.
When dry, the water is gone and the gum forms a very thin layer between the particles of wood dust. There is also airspace, which makes the shell lighter than one made from epoxy resin, which tends to fill every crevice. This airspace can be decreased by applying pressure once the shell begins to dry but before it's fully dry, to make it denser, but my result was dense enough to make a Djembe.
I would say relating your post to the origional thread,
The Carver in Ghana will probably be left with a load of wood chips rather than saw dust. How do wood chips fit into you equation.

I wood say, you'd need a hammer mill to make dust from the chips. How much are they i wonder. Look expensive enough. Speaking of which here is a video of one with a crazy music which sounds like a cross between, the bells by Jeff Mills, a talking drum and haitian percussion. Any one know where this music is from. It must be African i reckon.



People may say the chip is a waist product but the carvers i seen all let the local families use the chipped wood of my drums for cooking their food. It didn't seem like a waist to me.
#38923
Indeed it's a small prototype, to simply test the gum/sawdust composite.
And you're right, a full size shell would be needed to test strength for making a djembe from it. I would include long fibers for strength, as mentioned in previous post. Mixing in anything from cotton fiber, hair, hemp, reeds, grass, etc. will increase tensile strength. And very true hardness is not a measure of working strength.

Oh right, carving doesn't make sawdust. I imagine they'd be flakes, and curved or curled ( from what Ive seen) for the most part, as well as chips.

[Edit: I have removed a section about using the flakes, instead I agree with The Kid that they need to be processed into smaller material for gluing properly.]

ON MAKING MOULD FOR COMPOSITE SHELL
Make a central mould (the shape of the hollow space in a djembe) out of whatever (paper mache, clay and fibers, sawdust, or carved from wood).
Then cut it in half between the stem and bowl. This allows the pieces to be removed d separately once the shell is dry.
I would drill a hole in them so a rod or pole can be inserted to hold them steady (down the center). The two halves are linked by the rod. The hole can be created while forming the mold if its made of composite, or drilled if its carved from wood.
Next the outer surface of the mould must be waterproof (or resistant to whatever the glue is dissolved in).
Thus first the surface is sanded smooth. Then pores and gaps are filled with a glue (gum and water in my case) mixed with filler such as fine wood dust ( gathered after sanding with fine paper). Then let dry. Coat again with glue to make a smoother surface.
Next seal with varnish, laquer, or something water proof. Some tree saps can be used, but take heat to dry quicker, and must be the resinous kind, not water soluble gum. (Resin turns into rosin and then amber)
Alternatively wax or oil can seal the surface, but will require reapplication, as its not as durable.

[Edit: I also removed a section about applying the composite to the mould. I may post in its own thread when I have tested it some more.]
Last edited by batadunbata on Fri May 11, 2018 11:09 pm, edited 1 time in total.
#38927
it is on the mould.
Are you sure people want this uniformly produced drum. Ok no need to answer that,l i can ask someone with a remo. lol

The advantage of saw dust over the chips would be the cohesion power of the glue with be higher if it surrounds cells as opposed to groups of cells and there'd be more surface area to glue. The chips would produce more possibility of air inside the end material which would leave weak points in the end product. That'd be my reckoning.

Ultimately i think the best solution is invest in tools that would cut the wood up and build stave drums if environmental concerns are an issue . That is the best way to be most economical with the wood.
#38930
the kid wrote:
Wed May 09, 2018 11:51 pm
Ultimately i think the best solution is invest in tools that would cut the wood up and build stave drums if environmental concerns are an issue . That is the best way to be most economical with the wood.
That is certainly true for, say, congas! But djembe shape is not very well suited for staved drums
- if you steam bend straight staves (which is quite complicated process that requires a lot of energy), you'll get quite a slender bowl
- you could also jig-saw the staves, but then there'd be lots of waste anyway, or
- you could make separate staves for bowl and the base, but it 'd be tricky to join them together strongly.