Is your Pipe bag leaking air?
Let’s face it. The pipe bag can leak. And a leaky bag means air that is not being used to vibrate the reed, so you are working harder to play your pipes.
You want, no you need, your bag to be air tight. You can check this by plugging the drone and chanter stocks with stock stoppers. You then blow through your blowpipe inflating the bag to full. Assuming your blowpipe isn’t leaking, the bag should stay inflated. If it doesn’t you have a leak.
If you can’t hear the leak coming through the blowstick (valve, cracks, loose joint) then you can check the bag for leaks. The quickest way is to pretend your bag is a bike tire tube – submerge in a tub of water and see where the water bubbles are coming from. Another alternative is to use soapy water on joints, etc.
If the stitched seams are leaking, you can seal those with a wood glue. If your joints are leaking, you will need to re-tie your stocks. You might get away with using some electrician’s tape around the joints/stocks as a stop-gap fix (i.e. on the competition field) but this isn’t a long term fix.
If you have a leather bag and small bubbles are forming all over the surface, a good seasoning will probably fix the problem. Unfortunately if a synthetic bag is leaking all over, you likely need to replace it.
Leaky Stocks?
You also need to check your stocks for cracks. If they are and the crack goes right through, it will leak like crazy. Fortunately a tiny bit of carpenters glue will fix the problem. Put a dab of glue on the inside of the stock, and apply a vacuum suction on the outside so the glue is forced into the crack.