Hello
I read something here about the video where Mr. Diego Camuñas made several types of slings.
http://youtu.be/-ouNR6djZy4I am Spanish from Andalucia, and here the sling type used by goat keepers is very similar and perhaps is exactly the same.
The fibers used by Mr. Diego are form several plants. The first is "pita" Agave americana. This species is not indugenous from Spain and it was boght here about the 16th century from Mexico.
The second fiber he uses in a three plait braid with a three branched pouch and very rough sling is "esparto" Stipa tenacissima.
The third sling he made with the bark of a bush called "torvisca" also known as "torvisco" Daphne gnidium.
Mr. Diego in a different video
http://youtu.be/XENlaEIHTGI where he wears a hat says that he cut the "pita" (Agave americana) leaves in full moon, so the plant has its sap down and he shows it rubbing the fresh fibers against his face without any allergic reaction.
The accent which Mr. Diego speak it is not the Balearic accent. In the comentaries of the fist video Orestes Pérez says that his accent is from Extremadura, and it is very similar to the typical accent of some parts of Andalucia.
I see that some of you master very well the technique of braiding slings.
One thing very important that Mr. Diego says is about the pouch. When you make a sling and make the pouch you must split the braid in two branches. You wil notice that there is one strand longer that goes from side to side of the width of the sling in that point. Where the two branches of thew pouch join there is the same kind of long plait. If that strand breaks the sling falls apart.
So you must be care in which side you put the stone. As the stone can break this strand.
You must put the stone in the same face of the pouch that you work when you braid the sling because the weak strand is in the other face and when you throw the stone, this will not touch that weak strand when it begins to fly.
You can see the weak strand at the right of this pic where the retention cord joints with the pouch.
The other weak strand is under the sling where the pouch joints with the release cord that is thicker.
So that stone is placed under the sling, and you must place the stone on the upper face of the sling to avoid that the weak strand breaks when shooting.
I hope don't bother you.
Best regards.
P.D. THE SLING IN THE PIC I VERY FINE, AND WELL MADE.