I think my bags have lost their airtightness. I’ve plugged into someone else’s bag and there’s such a difference in the effort involved in keeping it pumped up. On account of this i’m thinking maybe i need to be doing do something to seal the bags i have. I thought someone might have written a guide online giving instructions as to go about this. The last thing i want to make them worse though. Perhaps someone might be able to offer advice. Thanks, John
Jolly good luck. I had a leaky 11-year-old bag on a set I bought second hand, and ended up just replacing it. It had big balls of sealer rolling around in it when finally taken apart.
Yes, you can indeed find strange things in your pipe bag. You just never know what it could be!
It is a good idea to find out where the bag is leaking first, before attempting any type of treatment. I suggest you remove all the pipes from their stocks, cork or rubber stopper the stocks and inflate the bag fully. Plunge the inflated bag into a bucket of water and press on it. Note where on the bag the bubbles are coming from. Remove it immediately and dry the bag with a towel. You may see larger bubbles from one (or more) small area(s), like a seam or around the ties on one or more stocks. You may also see tiny bubbles coming from all over the bag. How you deal with the leaks depends on the leak location or if it is diffuse leaking from the whole bag. Different types of leaks require different remedies.
I’ve tried homebrew concoctions with varying degrees of failures and success. For a good solution, I would point you directly to Hardie’s Airtight.
I find the wet seasonings like “Airtight” have to be renewed from time to time.
Home made stuff, a beeswax and Vaseline (petroleum jelly) mix works well though the Vaseline can be preferentially absorbed by the leather leaving the wax on the inside of the bag. At the moment I’m into a 50/50 mix of Vaseline and microcrytaline wax. If the Vaseline soaks in, any residual wax will be more pliable and should stay on the surface of the bag.
Hmm…I assume that we are talking about a sewn leather bag
I’ve never used Hardie’s Airtight but have heard that it does not suit dry blown pipes, it being formulated for the Highland Pipes where breath moisture has to be considered…
I have , for many years, used a mixture of Beeswax and Olive Oil… about 45% wax to 55% oil… heated in a pan untill good and liquid , then poured in through the neck of a bag with stoppers in the other Stocks… Work quickly to inflate the bag by mouth stopping the outlet with a finger when full, and swirl the inflated bag about to spread the mixture… then place the bag on a hard chair and sit on, whilst it is still full of air… so as to press the mixture into the leather and seams of the bag.
Some testing of the mixture quantities should be made, prior to use, the need is to make a mixture that remains the consistency of axle grease at ‘cool’ room temperature.
The inflated bag should remain full and the sitter should not slowly decend.
Next step; pour out any excess sealant back into the pot and rub the sides of the bag to coat the insides evenly. Then I like to place the bag on a hard flat surface and use a roller (rolling pin, wallpaper seam roller or round reed sanding block etc) to squeeze out any remaining excess goup…
Last bit is to clean up the insides of all the stocks.
Some bag makers now offer new bags that do not need any sealing as the leather they have used is suposedly processed to be airtight… this is a much less messy alternative and on the face of it this is what I recommend today, pending long term testing of these products in the field that is!
Good luck… a totally airtight bag does make a hell of a difference , likewise one that gradually becomes more porous goes unnoticed as one’s arm and shoulder muscles grow stronger 
Geoff.
Geoff gives a good account as to how to seal most leaks at once. That is what I use for diffuse leaks where the bag is porous. If only one or a few spots at the stitches are leaking, I make a small amount of sealant of wax and lard or Crisco and place a 1/2 inch worm of it over the seam where the leaks are. I use a hair dryer to heat the area from the outside to melt the sealant, cork the bag and apply pressure so it goes into the holes. I have found this effective and long lasting for small seam leaks in bags and bellows. Sometimes just re-tying in stocks will fix leaks around the stocks. The method to use depends on the type of leak. The water test is best to determine this. A stitching leak can be fixed with much less mess than what Geoff describes. Be sure to thoroughly dry the bag and stocks after their immersion.
I also agree that Airtight and similar products rely on some moisture to keep from drying out, which they will do over time. I now use toilet bowl ring wax and add Crisco to soften it futher. They now contain microcrystaline wax rather than bees wax. Bees’ wax hardens over years of time.