Jerky Bellows

An on-line forum to discuss uilleann pipes

Moderators: the plod, snoogie, dropkick

Post Reply
User avatar
JohnnyKerr
Posts: 66
Joined: Mon Aug 17, 2009 2:49 pm
Real Name: Johnny Kerr
Location: Phoenix, Arizona, USA

Jerky Bellows

Post by JohnnyKerr » Mon Sep 27, 2010 7:34 pm

I recently acquired a used bellows by made by David Quinn and I am having trouble working with them. I've had to troubleshoot and maintain my previous bellows for simple things such as leaky valves, etc. but I'm not sure what the culprit is in this case. The bellows are very lightweight and feel great under my arm, and the hinge action is very smooth when not connected to the bag.

The issue I'm experiencing is that they seem to be jerking a bit when I pump air into the bag. I notice it expecially when I am trying to keep the second octave; it's as if they hesitate for a moment and then send a quick burst of air through the blow pipe, almost as if I had put my thumb over it and then suddenly removed it. Needless to say, it is making it difficult to keep my bag pressure under control.

It may be worth noting that I am playing them left-handed (and I did flip the valve accordingly). The gusset is very well worn-in but I can't discern any leaks. Based on your experience, what things are likely to cause this?

Thanks for your help,
Johnny

User avatar
PJ
Posts: 980
Joined: Tue Apr 05, 2005 10:49 am
Location: Baychimo
Contact:

Re: Jerky Bellows

Post by PJ » Mon Sep 27, 2010 8:29 pm

Maybe there's a 2nd valve where the air leaves the bellows (where it connects with the blow pipe). Have you checked that?
PJ

User avatar
JohnnyKerr
Posts: 66
Joined: Mon Aug 17, 2009 2:49 pm
Real Name: Johnny Kerr
Location: Phoenix, Arizona, USA

Re: Jerky Bellows

Post by JohnnyKerr » Mon Sep 27, 2010 10:39 pm

No, there's just the inlet valve on the bellows and the valve on my blowpipe stock. I've given most of the troubleshooting attention to the bellows as the blowpipe valve was not giving me any trouble with my previous bellows; however, I suppose it's possible that something has changed in there since I've been fiddling with the set to accept the new bellows connections. I'll give it a close look tomorrow and see if that isn't the source of the problem. If so then I'll surely be quite embarassed! Sometimes we get so fixated on what we think the problem is that we miss the simple solution! I'll check back in tomorrow.

Thanks PJ,
Johnny

Pipewort
Posts: 68
Joined: Sat May 13, 2006 11:48 pm

Re: Jerky Bellows

Post by Pipewort » Tue Sep 28, 2010 2:10 am

Is your shirt , or even the inside of your forearm, temporarilly blocking the inlet valve? Or is the connector pipe twisting and closing off? Both as you fight the second octave.

Pwrt

Mike Hulme
Posts: 180
Joined: Wed Aug 24, 2005 6:38 am
Location: Liverpool, UK

Re: Jerky Bellows

Post by Mike Hulme » Tue Sep 28, 2010 2:43 am

Check that the valve on the blowpipe moves freely when it is inserted into the bag stock. It may be catching on the bottom of the bag stock bore. Blow into the bag (by mouth) and squeeze the bag. If the valve does not lift and return cleanly then you will have the problem you describe. As in:

|......\........| normal operation

|.......)........\........(........| valve "hanging fire" as it catches in the bore

The leather hinge has to be very thin and floppy to allow the weight of the hinge to complete the return to rest.

User avatar
djm
Posts: 703
Joined: Tue Apr 05, 2005 9:27 pm
Real Name: David Moulton
Location: Canadia
Contact:

Re: Jerky Bellows

Post by djm » Tue Sep 28, 2010 4:43 am

The hinge of the valve should be at the top. The flapper is meant to hang down by force of gravity alone. If you've moved the valve you may have inadvertently reversed its intended position.

djm
Sex and drugs and uilleann pipes

learnthegrip
Posts: 26
Joined: Fri Feb 05, 2010 3:23 pm
Real Name: Ken Matley

Re: Jerky Bellows

Post by learnthegrip » Tue Sep 28, 2010 5:01 am

I had a similar problem with my DMQ bellows that turned out to be the blow pipe tubing kinking up. I replaced the 30 year-old rubber tube and all was well.

User avatar
JohnnyKerr
Posts: 66
Joined: Mon Aug 17, 2009 2:49 pm
Real Name: Johnny Kerr
Location: Phoenix, Arizona, USA

Re: Jerky Bellows

Post by JohnnyKerr » Tue Sep 28, 2010 9:00 am

@ Pipewort: The ergonomics of this bellows is such that my arm doesn't sit over the inlet. Also, David designed the inlet with holes in the side of it so it is impossible to close it off. Very nice aesthetically, and functionally.

@ Mike Hulme: I will inspect the valves more closely when I can sit down with the pipes after work today. Thanks for the easy-to-understand description.

@ djm: I moved the valve because the person who sold the bellows to me was right handed and I play left handed. I moved the valve so that the leather's hinge would be at the top for a left-handed player. I haven't touched the blowpipe stock valve and have been playing on that for just over a year now (also with the hinge in the proper place). As I said in the previous post though, it's possible it was accidentally rotated or something with all of the moving around this week so I'll take a look at that when I can this afternoon.

@ learnthegrip: I had been using a length of radiator hose which is so thick that it is virtually impossible to kink at such a short length. Yesterday I took delivery of one of NPU's bellows connectors and I didn't notice any change in performance after installing it. Kinking was one of the first things I watched for when troubleshooting and I don't believe that's the culprit.

More later (and thanks very much)...

Pipewort
Posts: 68
Joined: Sat May 13, 2006 11:48 pm

Re: Jerky Bellows

Post by Pipewort » Tue Sep 28, 2010 3:07 pm

An interesting problem, if all these options don't solve it. Is the clack valve sticking, from bag seasoning or some such, rather than mechanical obstruction?

Pwrt

User avatar
JohnnyKerr
Posts: 66
Joined: Mon Aug 17, 2009 2:49 pm
Real Name: Johnny Kerr
Location: Phoenix, Arizona, USA

Re: Jerky Bellows

Post by JohnnyKerr » Tue Sep 28, 2010 7:08 pm

Check that the valve on the blowpipe moves freely when it is inserted into the bag stock. It may be catching on the bottom of the bag stock bore. Blow into the bag (by mouth) and squeeze the bag. If the valve does not lift and return cleanly then you will have the problem you describe. As in:

|......\........| normal operation

|.......)........\........(........| valve "hanging fire" as it catches in the bore
Nailed it. I'm not sure why this problem manifested all of the sudden after working fine for over a year but after snipping small bit from the bottom of the flap I'm back in business. Thanks for talking me through it gents.

Off to play with my new/used D. Quinn butter bellows. So smooth!

brazenkane
Posts: 25
Joined: Mon Aug 09, 2010 12:30 pm
Real Name: K. Pádraig O'Kane

Re: Jerky Bellows

Post by brazenkane » Wed Oct 06, 2010 7:13 pm

David's bellows are unbelievably efficient! Amazing stuff, David!!!!

saskjoe
Posts: 20
Joined: Wed Jul 09, 2008 8:12 pm
Location: Saskatoon Saskatchewan Canada

Re: Jerky Bellows

Post by saskjoe » Sun Jan 02, 2011 3:43 pm

I solved a similar problem by inserting a stiff plastic hoop (from the little hanger that comes with new socks) far enough into the fitting that its arch contacts the middle of the flap.

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests