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bag making

PostPosted: Wed Jul 13, 2011 5:25 pm
by Dally
Even though this video is in German, which I don't understand, it is still fascinating. Markus uses surprisingly little glue and his seams are very thin compared to the bags I make. I wouldn't trust a seam that thin to stay air tight over time. ... re=related

The last couple of bags I've made have been non-stitched. I glue the flesh sides together with about an inch width of glue, turn it inside out so the flesh side is on the outside, then glue a strip over the outside of the seam. I haven't played these bags for years yet, so I don't know how well they'll hold up. I'm using them now on a bellows blown BP, a mouth blown BP, and a bellows blown SSP.

Does anyone have any thoughts on how bag construction and material affect tone? I am using a slightly thinner cowhide than I used to, and you can feel the vibration from the reeds in the bag as you hold it. I like to think it gives the instrument a mellow tone compared to the thicker leather I was using. There is definitely a difference in tone with Highlands pipes, sheepskin being the ultimate, followed by goat, then hide, then synthentic.

Re: bag making

PostPosted: Wed Jul 13, 2011 5:52 pm
by Francis Wood
Hi John,

Interesting question!

There can be no doubt that the material of the bag affects the tone. As you note, the bag itself vibrates and therefore it is radiating sound. You can hear this effect, deprived of most of its higher harmonics, when you stand behind the player in a fairly non-resonant environment.

Without knowing more precisely, I'd guess that a thinner leather would be less opaque to higher frequencies than a thicker material with more mass. The bags on musettes de cour were often of surprisingly thin leather. Perhaps its tonal properties were preferred.

I'd also guess that the presence or absence of a cloth cover also affects the sound to some degree.
As for the construction, it's the shape and internal volume rather than method of construction that is likely to count acoustically.


Re: bag making

PostPosted: Sat Jul 23, 2011 7:50 pm
by BobGraham
I made two bags of leather-look brown naugahyde upholstery material about a year ago.
I turned [hemed] and glued the edges1/2", and then joined them together with glue. Afterwards, I stitched for good measure.

No seasoning, of course, so I am not always having to clean the velveteen covers.
And no smells or fuming the reeds with volitile greasey stuff.
The weight of the material is close to bag leather.
And the material was a gift from a neighborhood upholster's remnants bin.

Bob Graham