I have had a leaking gaita bag for some time, I could still play it but it was not holding the pressure after sometime. Perhaps the stitch was being stretched and the air was escaping through the stitching (the bag material was airtight). It was an old bag I made, and I have changed my technique since then for making.
Today I undid the stitching of my bag, took off the strip of tape that I had around the edge which was used for decoration, and cleaned up the loose threads. I then started the process of sealing the bag with a waterproof/gutter sealant. I did this to both sections of the bag, leaving an unsealed section/trip around the edge of the bag. I put extra sealant around the drone stock holes. Once I had sealed all the bag I went and covered the edge of the bag using a thicker film of sealant, then I left it to dry over night.
Tomorrow I will silicone the edges of the bag again with the same sealant and press them together, then leave to dry.
Once dry I will sew the edges with thread.
I will then glue one side of the bag/edge and reconnect the tape that I removed earlier. This gluing is only to seal the stitching/holes. When that is dry, I will do the same to the other side. Once dry I will tie in the stocks.