djembe zoom

Advice and questions on making and fixing instruments
#38066
I had a skin that was a bit, well, gross. I also got a sore throat when I played it, so what do do?

I dyed it with an Antimicrobial Natural Pigment! (Black Walnut hull powder - boiled briefly and strained)
I also put a couple drops of Tea Tree oil in the pigment for good measure.

Heres photos from before and after, and a slideshow showing the first stage of the process and the results.
I also describe the effect on the sound and playability at the end.

First I scrubbed the skin with a "magic eraser" sponge (micro-abrasive) because it needed it.
Here's how it looked after scrubbing: (none of the discolorations remaining will come off)
DSC05282_20percent.jpg
Before dying (after scrubbing)
DSC05282_20percent.jpg (64.19 KiB) Viewed 349 times
Then I brushed the pigment on. I was careful to only apply it to a portion of the skin between drying and apply it in light coats (no pooling). It adheres better to more porous/abraded areas, less so to slick areas. It did not seem to color the sides very easily at all (noticeable in pictures)
After each coat I dried it with a hairdryer (slowly rotating the drum) until it sounded dry.
The new coats dissolve the old ones, so I tried different patterns. I liked the look of dots.
The slideshow only shows the first few coats, then I stopped photographing, so it skips to the results:
SkinDyingProcessResults.gif
Slideshow - showing first stage and results
SkinDyingProcessResults.gif (1.35 MiB) Viewed 349 times
And here's the still of the final result:
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Final Result
DSC05317_20P.jpg (72.75 KiB) Viewed 349 times
It feels better to play, because the surface is smoother and pops more easily.
The sound is mildly affected.
This skin to start with has very little oil in it, (old skinny goat - note the wrinkle lines) which makes it sound dry, with a fine dissonance.
The pigment acts as a sealant, so the surface is more unified in it's resonance, giving it more pop and causing it to ring more cleanly and forcefully. It forms a dry seal so it's not dampening.
It's not a major effect, probably because it's a light coat that doesn't penetrate deeply into the skin.
Overall I'm happy with the change, it's given it a bit more body and power.
More presence now, easier to adjust the sound (more accuracy and clarity) but it's lost a bit of subtlety, a little harder sounding, and it's got more attack (the sound starts more abruptly).
Very minor change. I would guess that if I recorded it before/after most people would say it sounds the same, maybe one or two people would say it's mildly different.

Fun experiment, but I was nervous. Thanks to those who shared their wisdom in my advice seeking thread. It helped me be cautious, and I did no harm to the drum, and caused no change in pitch.
#38114
Thanks Dr Tom. Oddly enough I didn't think of the image limit. I made the gif so people don't have to scroll down a bunch of images (tedious). Thanks for pointing that out though, good idea.

Thanks Rhythm House Drums, it took a bit of trying different things. With some planning the possibilities are endless.

Thanks Djembefeeling, I'll try to remember to update when it's played in a bit. Durability is a concern, that's why I'm planning to give it a (very) light coat of karite or lanolin. Otherwise I can imagine sweaty hands removing some of the dye. Not that my hands get sweaty playing, but I plan to share this drum, so who knows? :)
This wasn't the most durable way to dye a skin. It would be best to dye skins before stretching them on shells. The key to proper dying is to either soak in the dye for a long period (24hrs+), or do multiple dips, and rinse away excess dye in between. This way, only fixed particles of pigment remain, no loose ones. (I couldn't rinse this or it would get too wet)
Also, it helps to use a mordant before dying. This prepares the material for dying, and fixes more color. Skin is a protein, like Silk and Wool, so theoretically it can hold dye better than plant fibers, which are cellulose.

BIOMIMICRY of Tonewoods (Acoustically Resonant Dye)
This dye (Black Walnut Hull) was also selected for acoustic resonance, copying the chemicals present in the most resonant guitar tone woods (African Blackwood and Macassar Ebony).
It's a similar chemical to chemicals they contain. (They contain methoxy naptha quinones, and Black Walnut contains a hydroxy naptha quinone.) I was hoping instead of dampening the skin, the dye would help it resonate clearly. It seems to work.

Another biomimicry pigment would be Indigo, because Macassar Ebony contains Dios-Indigo. It would be more durable than the Walnut, because it creates a harder coating of pigment, but that would also harden the sound, and I didn't want to go too far in that direction. From my experiments Indigo also provides water resistance (to paper anyway) and strength (abrasion and tear resistance). It can be dyed over walnut or other colors for depth of color and to create an outer seal. (over yellow it makes green/turquoise, over red it makes purple, and all three makes a deep rich brown or black like Ebony wood)

Sidenote/Caution: Tannin dyes may "tan" the skin, making it harder and stronger but less flexible and less stretchy, affecting the sound. Might be useful for weaker skins.
#38117
Hmm, I am again very sceptial about sound. Dying a skin, does that really improve the sound, just because in the dye there are chemicals that are also present in tone woods?

I certainly wouldn't advice on sealing the dye with karité or any other grease. That will, for all I know, really deteriorate the sound of the skin. Also, I don't think it's a good idea to put a skin for 24 hours into a fluid to soak. As Michi often pointed out, that will weaken the cellular stucture of the skin. And we don't want that at all as drummers, no matter how good the skin might look afterwards - which I don't think they do:
Djembe-Trommeln-Ziegenfell-bunt.jpg
Djembe-Trommeln-Ziegenfell-bunt.jpg (25.14 KiB) Viewed 305 times
their paintings I think are something between corny and nice:

https://www.djembe-art.de/djembe-tromme ... malung.htm
#38121
I don't think it's a good idea to put a skin for 24 hours into a fluid to soak.........As Michi often pointed out, that will weaken the cellular stucture of the skin.
Yet it's ok to wrap up a skin to soften it up when it's wet. so it looks nice or is easier to break in. Like water will damage it yet people claim to walk on the skin or beat it off a tree or pole. Ah well...
#38122
Aren't you comparing apples with pears? As far as I heard, the softening of the skin is supposed to break the crystals within the skin that make it stiff. With the water soaking endlessly into the cells, the membrane of cells finally breaks, I think. A skin that was left for way too many hours in the water feels very different from a skin that was walked over or has been beaten to be soft.
#38123
I've never gone beyond twelve hours. I suspect that even 24 hours would be OK.
instrument-building-and-repair-f3/for-h ... t4083.html

The theories were discussed here anyways. I'm sure there was other threads too.

They are both process which have been claimed to change the cellular structure of the skin. I think it is safe to compare the processes or the effects of each. Plus they are theories so not proven.
#38127
A skin that was left for way too many hours in the water feels very different from a skin that was walked over or has been beaten to be soft.
That may be true but it doesn't prove that over soaking the skin is detrimental to the longevity of the skin. The over soaked skin returns to normal when it dries imo. It shrinks and goes hard. There may have been structural change inside the skin but hard to say with out a microscope or proof or an understanding of how the skin cells react to water like do they get saturated beyond repair etc..
#38128
The proof is in the pudding. Just try it. It happened twice to me that I was so distracted that I completely forgot about the skins soaking. Next day, roughly after 24-30 hours, I took one of them and mounted it. It teared before I even pulled the skin in the end. The other one kind of dissolved already, I didn't even consider mounting it. Both felt really slimy. very much like you could expect when the cellular membranes cracks and the stuff inside is set free.

The few instances I prestretched a skin it came out just fine. I don't know exactly what happened in the skin in both treats, and I don't really care that much. But if you ever go looking with a microscope, please tell me what you could or couldn't see.
#38129
Many years ago I was instructed to soak skins for half an hour to an hour, so that's what I did. As my experience and confidence progressed, I began to soak for longer periods until I have now soaked skins for as long as several days. There are skins that REQUIRE days of soaking. In a pinch, I'll soak ONLY for several hours.

The longer you soak skins the more workable they become and the longer they remain workable. To me, this is a good thing. It's important to pay attention and change the water when needed or bad things may happen.
#38131
The proof is in the pudding.
Is that apple or pear pudding?

Glad you shared your experience. I haven't experienced similar but i could accept there could be a time limit to soaking skins. What i do if i soak the skin for a long time would be hang it up and let it dry for a bit before mounting so it isn't so wet or messy. It does shrink back quick enough.

I wouldn't want the skin soaking in warm weather for too long as that is gonna start to rot and get slimy and stinky. I'd add to DrToms advice on changing the water to try keep the soaking skin in a cool place.
#38134
the kid wrote:I wouldn't want the skin soaking in warm weather for too long as that is gonna start to rot and get slimy and stinky. I'd add to DrToms advice on changing the water to try keep the soaking skin in a cool place.
Good point. One of the many details I omitted.

I've left skins soaking in direct sunlight on a hot day. It's a good way to hurry along the ripening process.
#38136
the kid wrote:
I've never gone beyond twelve hours. I suspect that even 24 hours would be OK.
instrument-building-and-repair-f3/for-h ... t4083.html
Since then, I've tried 24 hours on two occasions, and got bitten both times. It turns out that the skin isn't uniform but has some layered structure. The pigmentation is in the outermost layer. That layer seems to absorb more water and, while I was working those skins, started to separate and flake off. The net result were skins that had white patches where the outer layer had come off, surrounded by dark patches where the pigmentation was still intact.

As far as I can tell, soaking for that long didn't affect sound or longevity, but the end result was not as pretty. And, overall, the skins weren't easier to handle or work with as ones that have been in the water for only twelve hours.

It may well be that this doesn't happen with all skins. Some may have the outer layer a bit thicker, or whatever. But I'm limiting myself to at most twelve hours. There really is no difference between goat skins that have been in the water for six hours and for twelve hours, as far as fitting them is concerned.

I've had cow skin in the water for 24 hours, no problem. I've also seen cow skin that was in the water for 48 and 72 hours. I wouldn't recommend that. The skin really swells up when soaked for that long, and it gets very stinky…

Michi.