WBO 23 - Certandan Deep Strings

[Flamingo21]

I am not good at thinking ahead in a tangible way. Like, I need to have that coopered rim physically in front of me in order to be able to think about the next step. Not a useful trait to have when you're creating an experimental thing, like an instrument from a fantasy novel.

But hey, I'll get somewhere. Hopefully.

 

[Videojunkie]

If your ukes are any indication, you'll figure it out as you go, and it's going to all come together.

 

[Flamingo21]

If your ukes are any indication, you'll figure it out as you go, and it's going to all come together.

Thank you!

 

[Reedt2000]

Are you using the leather to suspend the top? Like the gasket holding a speaker cone to its frame?

 

[Flamingo21]

No, the leather itself is the top. As on a banjo.

 

[Reedt2000]

No, the leather itself is the top. As on a banjo.

I see, very cool. How are you gonna tension it?

 

[Flamingo21]

How are you gonna tension it?

The leather gets rivets, the rim gets hooks of some sort. Between the rivets and the hooks, a cord will zig-zag. Then I'll find a way to pull the cord taut. I have some ideas.

 

[Flamingo21]

Maybe like this cord here:
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[Videojunkie]

Maybe like this cord here:

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Those black blocks on the cords are the tensioners. By sliding them up and down, you can increase and decrease the tension on the top. Very old way to do that, and they can be made out of many kinds of materials.

 

[Crawforde]

Lessons from a drum.
Who’d a thought?

 

[T_Bone_TL]

probably want something along the lines of kerfed linings top and bottom like on an acoustic guitar.

Almost have that, with the blocks supporting the staves. Indeed, going back and looking, pretty much do have that for the one they are glued to now. And of course the coopered staves are strong when compressed, with their angled sides.

Pay close attention to how smooth the edge is that the leather pulls over. I'm a bit concerned that the leather may want to tear at the rivets/grommets - most of the leather drumheads I've seen have a continuous hoop that spreads the load into the leather. If so, well, Mark II will happen, presumably. If you don't go wild trimming the leather might even be able to use the same piece, if that happens at all. Here's a pretty good (if rather long, but hey...) explanation of how that works for a Djembe head. Djembe Reskinning - Afrodrumming

 

[Flamingo21]

Pay close attention to how smooth the edge is that the leather pulls over.

I'd already figured that out, so I gave the top of the rim a "roundover" using the circular sander and 40 grit.

 

[boxerrider]

Videojunkie posted an elegant approach to tensioning. If you want a coarser one, you can go with the twisted cord method.
Example:
Two rubber bands around a board. These would be the cords attaching your leather top.

Bands overlapped with a paperclip in-between. You can use a piece of wood here - it just needs to be long enough to apply sufficient pressure.

Use the paperclip (piece of wood) to twist the bands (cord) until you have the tension you want, and then position it perpendicularly so the long end rests against the body to keep it from untwisting.

 

[KidAmnesia]

I'd already figured that out, so I gave the top of the rim a "roundover" using the circular sander and 40 grit.
View attachment 4951955

You should probably have a flat surface all arround the rim if you want the leather to have a uniform tension and surface.
And I suspect that making a ring that pulls evenly from the leathercwill be way better than pulling from rivets on the leather itself; that's how almost every drum head is tightened. I suspectnthe rivets will start to deform and tear apart under tension.

As for preventing colapse, you could cut another ring of plywood to fit inside the rim and support it. Or make a lining out of bent strips of hardwood; don't use kerfing as it won't give any structural support from the sides.

 

[Matt Liebenau]

Yeah, ignore my comment about kerfed lining. I forgot about the leather and was thinking of a wood top.

 

[Flamingo21]

People, we need to sort something out.

We all know it makes sense for the leather top to be under high tension. And this means it needs to be fastened with a hoop instead of rivets, or it will tear. And this also means the coopered rim needs strengthening, to withstand that high tension. Many of you have offered good ideas on this.

But the reality is a different one. When the Buildoff began I had no clear build plan yet, so I didn't do anything for a week and a half. Then I just got started in a happy-go-lucky manner, making things up as I went. And now I'm overseeing what I have so far, and I know that high tension is not going to happen. The rim is simply not up to it. To strengthen it, it would need a close-fitting inner lining, which needs a better woodworker than I am. And I feel the hoop for the leather is also beyond my skills. Also, fastening that hoop reliably to the construction we have now, would seriously compromise its character.

My father, a painter, told me there'd usually be a point where the painting takes over, and you as the artist can follow and see where it leads you. Many of his paintings ended up being different than what he imagined at the start. Many of his paintings are beautiful for that reason. I'm going to take his advice here.

To make the high tension top happen, I have to build differently. To plan. To calculate. To have experience that I don't have. Will I ever? Maybe. Maybe one day I'll restart this build and make it happen.

But for now, I'm going to let myself be guided by what I have so far. There won't be a high tension top. What will there be instead? Who knows.

As so often, I find that your comments have been indispensable. The hive mind really helps me think, sometimes in a straight line, sometimes in paradoxical ways. So I just say: thank you.

 

[Will_White]

People, we need to sort something out.

We all know it makes sense for the leather top to be under high tension. And this means it needs to be fastened with a hoop instead of rivets, or it will tear. And this also means the coopered rim needs strengthening, to withstand that high tension. Many of you have offered good ideas on this.

But the reality is a different one. When the Buildoff began I had no clear build plan yet, so I didn't do anything for a week and a half. Then I just got started in a happy-go-lucky manner, making things up as I went. And now I'm overseeing what I have so far, and I know that high tension is not going to happen. The rim is simply not up to it. To strengthen it, it would need a close-fitting inner lining, which needs a better woodworker than I am. And I feel the hoop for the leather is also beyond my skills. Also, fastening that hoop reliably to the construction we have now, would seriously compromise its character.

My father, a painter, told me there'd usually be a point where the painting takes over, and you as the artist can follow and see where it leads you. Many of his paintings ended up being different than what he imagined at the start. Many of his paintings are beautiful for that reason. I'm going to take his advice here.

To make the high tension top happen, I have to build differently. To plan. To calculate. To have experience that I don't have. Will I ever? Maybe. Maybe one day I'll restart this build and make it happen.

But for now, I'm going to let myself be guided by what I have so far. There won't be a high tension top. What will there be instead? Who knows.

As so often, I find that your comments have been indispensable. The hive mind really helps me think, sometimes in a straight line, sometimes in paradoxical ways. So I just say: thank you.

You could fake it, put a thin plywood top on, round over the edge then just gently tension the leather with a little glue. It will still work acoustically ok.

FWIW the hoop you have should work fine tension wise, it's just a matter of smoothing the top and figuring out how to tension the leather.

 

[boxerrider]

I don't think the body hoop would have a problem. I have concerns about the upholstery leather - it is usually pliable, and I think you want something stiffer. When you do decide to go in that direction, then following the primative drum makers practices would be sound. They have been there and done that.

 

[Flamingo21]

I have concerns about the upholstery leather (...) I think you want something stiffer. When you do decide to go in that direction, then following the primitive drum makers' practices would be sound. They have been there and done that.

Indeed they have! So that's one direction I will let my thoughts wander and see what I find.

I'm looking at images like this one. (Funnily enough, it has the leather cut into kind of a pointy shape. Now if you go back to my sketch, you'll see that I spontaneously drew the leather in that kind of shape. I didn't even realise then that the shape exists in real life.)

Another direction my thoughts are wandering is a spring system under the bridge. Banjozilla has this, and I suspect it may be kind of a necessity, brought about by the large physical scale of the instrument. We'll see about that.

And then of course there's things like this.

It seems fitting to decorate the head in some way, but I'm not sure I'll have time for it.

Lots of possibilities everywhere.

 

[Videojunkie]

Indeed they have! So that's one direction I will let my thoughts wander and see what I find.

I'm looking at images like this one. (Funnily enough, it has the leather cut into kind of a pointy shape. Now if you go back to my sketch, you'll see that I spontaneously drew the leather in that kind of shape. I didn't even realise then that the shape exists in real life.)

Another direction my thoughts are wandering is a spring system under the bridge. Banjozilla has this, and I suspect it may be kind of a necessity, brought about by the large physical scale of the instrument. We'll see about that.

And then of course there's things like this.

It seems fitting to decorate the head in some way, but I'm not sure I'll have time for it.

Lots of possibilities everywhere.

Your picture examples are using rawhide as opposed to tanned leather.

With rawhide, you apply it wet, and as it dries, it shrinks pulling it taut.

Tanned leather on the other hand, will stretch when wet, but won't contract in the same way as it dries.