Remedy for a leaking loading tap/advice re lubricant of piston seals

[andrewM]

My earlier post on a leaking loading tap (on my BSA Standard) caused me to meet the technical expert who works at a local gunshop. I thought his advice was worth including as a separate thread. He is probably well into his 60s and seemed to be experienced and well informed. Having limited knowledge about the finer technical points of springers and loading taps, I carefully noted his advice. Here it is:

1 Lubricant: He said there was no need to introduce Weboil or any equivalent these days, into an air chamber, as all oils create dieseling to some degree. He gave me a small tube of 100% pure silicone oil (core-rc.com), actually used for the car racing business (and expensive at £15 for 60mls). Some three to five drops were to be introduced after every tin of pellets. I wonder if anyone would like to comment?

2 Leaking tap loader: he said a new tap would be expensive to buy and fit. A better alternative, he said, which will work as well, is to dismantle the tap, place tissue in the centre hole, and spray on an aerosol external chain lube, then restore the tap to its position. This lube sticks to the surface - as it would to a chain saw, and will seal the gaps 100%. As an afterthought, however, it then occurred to me that it might also seal off a section of the air from the chamber if the tap-loader rubs against the exit hole from the air chamber. I might call him next week to seek further advice on that.

3 He also mentioned that it was good practice to fire the rifle with the tap loader in the upright position as it helped to mould the piston seal to the end of the chamber.

So, I thought it worth introducing this as a new thread on this site, so others can benefit and/or debate the merits of this advice.

Meanwhile, I would prefer to have my BSA Standard inspected by an expert but I still need to find one!

Regards
Andrew.

[RichardH]

I would look for another expert.

[pegasus]

I would look for another expert.

Aye, you need look no further than here, Ed Bear, and Garvin spring immediately to mind, and there are quite a few more

[AC99]

My earlier post on a leaking loading tap (on my BSA Standard) caused me to meet the technical expert who works at a local gunshop. I thought his advice was worth including as a separate thread. He is probably well into his 60s and seemed to be experienced and well informed. Having limited knowledge about the finer technical points of springers and loading taps, I carefully noted his advice. Here it is:

1 Lubricant: He said there was no need to introduce Weboil or any equivalent these days, into an air chamber, as all oils create dieseling to some degree. He gave me a small tube of 100% pure silicone oil (core-rc.com), actually used for the car racing business (and expensive at £15 for 60mls). Some three to five drops were to be introduced after every tin of pellets. I wonder if anyone would like to comment?

2 Leaking tap loader: he said a new tap would be expensive to buy and fit. A better alternative, he said, which will work as well, is to dismantle the tap, place tissue in the centre hole, and spray on an aerosol external chain lube, then restore the tap to its position. This lube sticks to the surface - as it would to a chain saw, and will seal the gaps 100%. As an afterthought, however, it then occurred to me that it might also seal off a section of the air from the chamber if the tap-loader rubs against the exit hole from the air chamber. I might call him next week to seek further advice on that.

3 He also mentioned that it was good practice to fire the rifle with the tap loader in the upright position as it helped to mould the piston seal to the end of the chamber.

So, I thought it worth introducing this as a new thread on this site, so others can benefit and/or debate the merits of this advice.

Meanwhile, I would prefer to have my BSA Standard inspected by an expert but I still need to find one!

Regards
Andrew.

Many years ago I successfully sealed a leaking tap on a Webley mk3 which had been ill treated by a previous owner. There were quite obvious small scratches and gouges on the outer surface of the tap presumably from mis-treatment or poor maintenance from a previous owner..
It was achieved by an electrolysis technique (electro-deposition) - applying a very thin coating of copper to the tap body, re-fitting repeatedly turning tap in tap chamber thus filling in the deformities on the tap surface resulting in a close mating fit and no air leakage.
This was done when I was working- now long retired - and had access to the chemi-lab at work. After thorough cleaning and de-greasing the tap was initially masked off to protect areas of tap where copper should not be deposited ie the tap lever, far end of tap remote from lever and plug bore hole with close fitting rubber bung.
The process was to make up a solution of copper sulphate (CuSO4) in a glass beaker, attach a copper wire to the tap by firmly twisting it for good electrical contact and attach other end of wire to the negative terminal of a battery. Then attach a small chunk of scrap copper to another short length of copper wire and connect to positive terminal of same battery. When this connection is made copper from the scrap will be deposited on the tap surface.
Lower the scrap copper on its wire into the solution and then carefully lower the tap into the solution and after a period of time copper will be seen to be deposited on the un-masked surface.
Remove tap and rinse thoroughly and wipe dry.
Thickness of coating will depend on battery current and process time. A very thin deposit is all that is required - sufficient to fill in surface blemishes and compensation for excessive surface wear. It can be done at home if you can obtain some copper sulphate crystals and distilled water and any battery will do. In the absence of suitable masking material the tap lever will need to be held clear of the surface of the solution.
This is a cheap solution to renovate an otherwise useable rifle and revive its original power. The only downside is the rather obvious traces of copper filling the gouges and on the tap surface.
If you are feeling brave and can locate some copper sulphate then give it a try. At the time of carrying out this process I was unaware of the possibility of using chain lube.
Aubrey

[deejayuu]

The lever can , of course, be removed from the tap before treatment

[andrewM]

Thank you, all, for the responses.

Reading yours, Aubrey, I am reminded of the truism that most of Britain's inventions appear to have originated in small workshops and potting sheds. I think our people have a wonderful knack of inventing solutions to problems, often with limited materials, as you have done.

Chain lube seems a most interesting possibility but I am worried it might impede air from the air chamber, if it touches it, unless the transfer hole is set some way back. I will try to contact the technical person who provided the advice when he returns next week. Perhaps I should send my rifle to you to sort out!

Rgds
A

[andrewM]

From my earlier thread, I have received this timely intervention and it contradicts the views of the technician who imparted this advice - posted above. It is important enough to repeat here, and I am glad I proceeded with caution, taking no action until I notified the experts here.

This post was from edbear2:

"re. the above
1...Do not use silicon oil anywhere where it will leach onto parts and cause metal to metal contact, as it will if put into the chamber...just google silicon oil metal to metal, it is a plastic lubricant and exactly the WRONG stuff to use! (and I have been in F1 racing and aviation at the pointy end since the mid 90's so am well up on exotic lubes).

2...Total rubbish...and may even be uneeded if you follow my earlier advice you may not need to do this if you have checked the originality / fit as described.

3...I have heard of this back in the early days of ptfe washer replacements, but not for leather....You are not moulding the end of the washer, you are concerned with the sliding fit / air seal I would say not slamming the piston into the cylinder end (which is what will happen if you DO have a leaky tap...This will wreck the washer screw...believe me I have repaired enough over the years.

All the above IMHO, as I have said your gun may be fine and just need 1/2 and a fiddle to establish the problem...Have you tried various pellets to establish the 8 pound output as various types can make over 1 pound difference, happy to send you a few original Wasps and FTT's to get a benchmark as normally these are the ones that perform the best through the chrono.

ATB, ED "

Unquote

Rgds
A

[Airsporter1st]

He makes a couple of good points, but unfortunately these are negated by a couple of bad ones.

Use of a very viscous lube on the mating surfaces of the tap is a known 'cure'. I would't worry about the lube getting where it shouldn't - it needs to be used only sparingly and any that actually does get into the loading port will soon be shot out with the pellets.

P.S. 'Apiezon L' is said to be a very good choice for this application. Never tried it myself, because by looking after my guns, I've never had a leaky tap.

To echo what others have said, don't put pure silicone oil into the compression chamber. I won't even use it on external wood or metalwork, due to risk of migration and causing galling wherever there is metal to metal contact.

[jjjjjj]

I would not use silicone oil on my guns, I have seen the damage it does when it gets on metal to metal contact from a few air rifles I have repaired for people.

[Garvin]

Interesting threads Andrew. I will add an abridged version of the advice to the vintage BSA forum for future reference. As always, follow Ed's advice if you know what's good for you - there's no greater expert on the workings of these guns and while your 'expert' may know a lot about other things, he clearly doesn't know his old BSA air rifles!

The silicon oil advice is a tricky one, since it's right that it's a OK for leather, but not under any circumstances for metal on metal. Abbey's SM50 combines both silicon and moly and is fine for metal lubrication, although I've never quite understood the relationship between the two ingredients. Presumably the moly counteracts the stripping effect of the silicon carrier.

As Ed says, worn taps are rare, though sadly you do come across some that have been scored by foreign bodies entering through the loading hole. The only really durable way of repairing wear when it does occur seems to be nickel/copper plating, as mentioned, although the temporary cure of using chain oil sounds plausible to me (I'm sure Paul is right that you shouldn't worry about surplus). I've used very heavy grease to tighten loose taps in the past and it works for a while.

Some of the best advice is don't get hung up on the tap when looking to boost power. I've heard it said that the amount of air lost through a leaking tap is miniscule as a proportion of the whole, although others obviously believe taploader breech leaks are an important source of lost power when they reach a certain severity. Perhaps best to make it the last thing on your list after attending to piston/spring/barrel/running-in issues first?

[ccdjg]

This is a cheap solution to renovate an otherwise useable rifle and revive its original power. The only downside is the rather obvious traces of copper filling the gouges and on the tap surface.
If you are feeling brave and can locate some copper sulphate then give it a try.
Aubrey

This is a great idea for a permanent solution, especially as copper is so malleable and will adapt to any irregularities on the tap surface. I have used a similar technique to build up worn threads and fill pits on gun metalwork, but plating with iron rather than copper. A bit trickier but very effective.

[andrewM]

Thank you, Airsporter1st, ccdjg, Garvin and jjjjjj, for your further feedback, much appreciated.

I looked at the Apiezon link but it is expensive stuff, at over Euros 100/tube.

Garvin, yes this thread is likely to be of interest to BSA enthusiasts on the vintage forum - perhaps more because it will place them back on the straight and narrow if they consider straying, as I did - and the emphasis appears to be to keep well away from pure silicon; I have no doubt it would leak elsewhere. I wonder if the SM50 is feasible, however, given it is a combination but would the moly and silicon part from each other?

I am certainly following Ed's advice - no question about it!

I think I agree with you (and Ed) when you say that there is a risk one might become too focused on a leaking tap. In fact, when I put my finger over the loading bay and fire a shot, I can feel no pressure and that suggests the leak is slight - albeit less so when one applies the cocking test (de-cocking with tap open).

This leads me back to the original dilemma: I need someone to bring the 1939 BSA back up to its optimum ability! Quite prepared to pay for it too!

Rgds
Andrew.

[Shed tuner]

Personally I say just do it yourself following the excellent advice on here.

However if you are really stuck, you are welcome to come by sometime; I can resurrect most things

[T 20]

I once read that BSA used this on loading taps :-

https://www.rocol.com/products/kilop...damping-grease





All the best Mick

[Garvin]

For future reference, lots of BBS wisdom on this issue saved here.

Edit: Andrew as for your pleas for a gunsmith who you could pay to do the work, there are various skilled 'smiths around the country, although none is likely to come forward publicly on this forum for fear of being seen to tout for business, which is forbidden (though I suppose they might PM you).

Jon's offer of help is generous but he's right when he suggests doing it yourself. The old BSAs are extremely simple to work on and you will enjoy it, as well as knowing exactly what's happened inside your rifle. Maybe the best thing would be to advertise for an enthusiast who lives near you. Where is Pulborough - I've never heard of it, sorry?