One of the early posts on the Society website Forum asked the question;
“My smallpipe bellows are not working as efficiently as they used to ( not completely airtight) I plan to treat them with a mixture of neatsfoot oil and beeswax but I'm not sure of the mix ratio and required amount. Can anyone enlighten me on this procedure? All comments/info gratefully received”
Common Stock invited pipe-makers to come up with answers to this question; below are their responses.

From Nate Banton:
“Here's a quick rant:
I have no recipe for treating bellows, but I do have some thoughts on the need for such recipes.  While I think the old ways of doing things are generally the best ways, that theory and myself part company when it comes to bellows.  There is no longer any reason to make a bellows that needs seasoning, either when it is made, or even during its life span.
I don't currently make my own bellows, but I have made many in the past and will make many in the future.  There are three ways that I have seen that will allow one to make an airtight bellows that will give many years of airtightness with no seasoning.  All of my experience with no seasoning bellows, as an uilleann pipe maker's apprentice and as a smallpipe and Border pipe maker, has been with the "tacked" style of bellows, and I think this is a superior way to make an airtight, no seasoning bellows, but I suppose it may be possible to still make such a bellows using the "more traditional" sewn style.”
Nate went on to say that leather was available of a suitable quality so that bellows should “last twenty years without need of seasoning”. He does however add that “at least in the US, the leather industry is rather unreliable at the moment, and while a particular leather supply may be perfectly airtight one moment, the next time you order it is not.”  He goes on to recommend the use of a two layer gusset with barge cement to hold them together.  “Whether it is due to the two layers of leather, or (much more likely) due to the use of a layer of barge cement (or I have used the less deadly water based contact cement), this is a simple way to make a bellows that will not need seasoning. “
Nate recommends the use of a “man-made second or third layer in the gusset to form a permanent airtight layer.  There are many many (rubber, plastic, gortex) materials available that can be glued to the inner side of the gusset that will create an airtight layer. “
Finally Nate adds:
“It is so desperately important to have as near to a 100% airtight set up as possible with bagpipes to allow the most comfort when playing.  It is an unwieldy beast the bagpipe!  We don't need to make it any harder by allowing our bags and bellows to reduce our playing efficiency.  There are modern means and materials to make a 100% airtight gusset...”

From Jon Swayne:
“I've never used neatsfoot and beeswax so I don't know what a good proportion would be. I ‘permanently’ seal my bellows leather during the making process, so that they don't need any seasoning until they are worn out.
“Although I have done it once or twice, I don't have much experience of carrying out what seems like a tricky procedure - getting enough, but not too much, of the mixture inside a strangely shaped object, so I won't offer any advice.
“But if I wanted to treat bellows I would use a mixture of Vaseline and beeswax, in the proportion 6 parts of vaseline to 1 part beeswax by weight. This gives a cold consistency like a stiff soft margarine, with a less oily feel than an oil/beeswax mixture and a wider temperature range (I think).”
[Editor; I asked Jon about applying this mixture]
“You would apply it hot. Melt it in a bowl or jug in a saucepan of slowly simmering water.”
[Editor; I also asked Jon the following question:]
“When you say 'till they are worn out' do you mean when the outer  surface of the leather cracks and flakes? Is there a suitable treatment for deferring this kind of deterioration? My bellows are just starting to go like this at the folds; I don’t want them to go the same way as my old leather jacket. Will just about any leather treatment do, or have you something particular to recommend?”:
“How long the bellows leather lasts probably depends on the quality of the leather as much as anything. If it's a very dry, stiff tan then it's life might be shorter than a soft supple tan. On the other hand bellows leather doesn't want to be too supple or it doesn't work very well.
“Leather dressings design to keep leather supple would might prolong life, but much depends on the type of leather and the design of the bellows. It would be a mistake to make a hard and fast rule.”

From Julian Goodacre:
“The seasoning that I have always used for bellows and bellows blown bags is made from beeswax and olive oil. The oil softens the wax and helps it penetrate deep into the pores of the leather and the oil nourishes it, keeping it supple and airtight for many, many years.
“This seasoning is easy to make and is tasty to eat! It is an enormous comfort to know that if I was washed up on a desert island I could nourish myself by chewing on my bellows.
“Approximately one part beeswax to four parts olive oil (by volume).
“Place this in a jam jar in a microwave and slowly heat it. It takes quite a while to melt the wax so I usually chop it into small pieces to speed the process. Then let it cool to room temperature and see if it sets with a similar consistency to Vaseline or soft margarine. After that you can add a bit of oil or wax and re heat it to achieve the required consistency.”
Julian attached the following method:
SEASONING BELLOWS
Wear old clothes!
Remove the bellows inlet valve and block up the outlet. Pour some seasoning in through the valve hole. You need to manoeuvre the bellows quickly while it is still runny to ensure it covers all the inside surfaces of leather with a light coating.  It is easier to pour in small quantities and work it into one side and then repeat the process on the other side. If you use too much you get clots of it forming which can clog up your transfer pipe. These will not damage anything but can be a bit of a nuisance (and sometimes embarrassing) until you get them out of the system.  I suppose if you have a poorly made set of bellows with horrible big leaks you could add more wax to make it thicker. This might block the leaks temporarily,  but it is best considered as a ‘desperation measure’ and not a long term solution.
I oil the leather inlet valve with a drop of almond oil.For ‘Advanced Readers’ I advise an exhaustive and fascinating  series of four articles written on stitched bellows making by David Quinn that was published in The Pipers’ Review. (The International Magazine for Uilleann Pipers). David bases this work on his considerable experience of making bellows for Irish pipes, but it nearly all of relevance to makers of all types of bellows. Twenty one pages of wit, wisdom and bellows insight!

THE PIPERS’ REVIEW VOL XXIII
Part 1    Making a stitched bellows.         No 1 Winter 2004
Part II     Preparation of the gusset.        No 2 Spring 2004
Part III     The wood.            No 3 Autumn 2004
Part IV     Hinges, belts and valves.         No 4 Autumn 2004[Editor’s note; these articles are available on-line to subscribers to the Pipers’ Review at http://uilleannforum.com/forums/viewtopic.php?f=7&t=389]

From Hamish Moore:
“There are two Essential Factors in Bellows efficiency; Airtightness and Mechanical issues.
A.  Airtightness.
It is imperative that bellows are airtight.
If it is suspected that air is leaking then a simple test must be carried out to check. Plug the exit with a finger or cork and squeeze the bellows as would be done when playing. If the bellows deflate at all then they are not airtight.
Potentially, there are four problem areas.
The surface of the leather.
Diagnosis – water spread on the surface of the leather will produce bubbles when the bellows are put under pressure.
Treatment may or may not be successful depending on the state of the leather.
Prepare a mixture of 75% Neetsfoot oil and 25% melted beeswax.
Remove the housing of the non-return valve and pour 50 ml of the oil/beeswax mixture into the bellows. Work the mixture into the leather. More oil and wax can be used if it doesn’t appear to be enough.
Drain any excess.
If the oily mixture leaks through the surface of leather then it is unlikely that the treatment will form a long-term solution to the problem, as the leather is no longer fit for purpose. In my experience there is no point in persisting with such bellows and new bellows should be purchased.
The Inlet Valve.
Using the same airtightness test; if air can be felt escaping from the inlet valve then the problem must be investigated. It must be determined whether the leaking air is coming from the joint of the valve housing with the bellows or the valve itself. If it is the joint then this can be tightened by roughing up the hemp or adding a few layers of cotton thread.
The most common problem however is that the valve is not seated correctly. In particular if the arm of the valve is too long then there will be gap between the leather valve and the flat of the wooden blowpipe. By holding the valve up to a light source this gap will be easily seen. The solution is to re tie the valve, ensuring that the valve fits flat on to the wood leaving no gaps.
In many cases the valve can successfully be retied but it may be necessary to replace it.
The outlet pipe and the join to the blow pipe.
Again, using the same diagnostic test as described it should be able to isolate the source of the leaking air and appropriate action should be used to fix the leak.
The stitch line where the leather is stitched into the wood. It may be possible to solve the problem of leaking air from this area by rubbing beeswax into the stitch line.
B. Mechanical Issues.
Length of the blow pipe.
It is very important to adjust the blowpipe to be the correct length so that the arm presses on the bellows towards the back of the paddles.
If the blowpipe is too long, the bellows are pushed round so that the right elbow will be in contact and pushing the bellows too close to the front and thus producing a mechanical inefficiency. In this case, the arm may also interfere with the inlet valve.
If the blowpipe is too short, there may be a repeated problem with the blowpipe joint popping out.

The leather cheeks may not hold their shape and become concave when the bellows are filling with air. This produces a huge efficiency problem. In this case the leather will have lost sufficient tensile strength to retain its convex shape and it is unlikely that the problem can be fixed. New bellows should be purchased.

SUMMARY

If you’ve read this far, you will have realised that there are no firm answers to this question; whether you use beeswax [some agreement on that,mat least] with neetsfoot oil 1:3, olive oil 1:4 or vaseline I:6 or whether you are lucky enough to have started off with a well-made set of bellows. Perhaps the answer is to ask the maker of your pipes for their advice and take that. One thing is certain, a bellows that is not airtight is going to spoil your piping life - as Nate said “It is so desperately important to have as near to a 100% airtight set up as possible with bagpipes to allow the most comfort when playing.  It is an unwieldy beast the bagpipe!  We don't need to make it any harder by allowing our bags and bellows to reduce our playing efficiency.”