How do I lubricate a leather piston washer?

[OldBrad]

I am restoring an antique Mk1 Webley pistol. I have purchased an original looking leather washer, but it is as dry as a bone and rock hard.
What should I soak it in to restore its flexibility?
I am in England where gun supplies are hard to find. I see some other posts about appropriate lubricating oil. Would hydraulic oil or common machine oil be appropriate?

[bill57]

In my experience if it has gone rock hard, as you describe, they can be impossible to soften. You would be better off fitting a new one, and it shouldn't be hard to find.

Oops, I've mis-read that completely. Neatsfoot oil is your friend, available from saddlery suppliers usually.

[mdunn]

Neatsfoot oil will do the trick. Atb mick

[Phil Russell]

Yes, neatsfoot is very good but be aware that when 'softened' the cup may be a tad oversized and you may need to 'fit' it.
When I have been making cups from leather (not bought an actual cup) I frequently use 'leather softener / stretcher' to get the leather started on its journey. This softener is just IPA ... not the beer sort but IsoPropylAlcohol. Come to think of it I have never tried the India Pale Ale version. After an application of IPA the leather does get softer and then I immerse it in the neatsfoot for a day or two although at times I admit to having used the Webley oil used for pistols ... not sure if this was Weblube or Webley gun oil?? I think one was sold for pistols, the other for rifles?
Cheers, Phil

[Muskett]

I'm no expert here.

Fast acting pressure chambers do produce some heat. I'm unsure if normal leather oils can handle that heat???
Maybe just a gun oil which is designed to handle more heat might be better than a natural linseed/beeswax type???

To get a hard washer soft then that might take some warmed oil to give it a better chance. Warm, almost hot, was commonly used in the gun trade to do all sorts of stuff. Could take a good few hours if not a few days as the oil has to get deep into the old thick leather.

There really isn't much to leather washers. They are really efficient, and find their own equilibrium of state. I'm not sure once leather is "dead", gone hard, if it can be restored. Maybe easier to find some fresh leather and just cut to size. Start thick and stack if necessary.
Its not an exact science, so expect some playing about. They take quite some shooting in to find their happy place, but then great for years and years. Lack of oil and use is the killer.

[Phil Russell]

Some piston washers are as you describe ... basically like a stack of metal washers or indeed just one washer of the correct thickness (I suggest 3-4mm minimum). But other washers are cup shaped where a leather disc has been formed to have a raised perimeter edge. Very often the centre of the washer will have a smaller diameter leather (or other material) disc in place with the raised edge of the washer containing this central disc. This arrangement is good because it presents the outer surface of the leather on the cylinder wall rather than the cut grain that you get by stacking leather discs. Generally speaking the cup washer with a fitted centre tends to be more common. They are not too difficult to make with basic tools and patience.

Cheers, Phil

[Neil54]

I soak overnight in neatsfoot oil.
A little goes a long way.

[Mark Palmer]

As already stated, neatsfoot is the way to go, Protek Supplies sell tiny bottles of it under a couple of quid , plenty enough for a gun build and a few years maintenance

[T 20]

An old gunsmith once posted on a forum that he used Lard to lubricate leather piston seals.

This may sound mad when you first read it but Lard is a constituent of Dubbin that you use to treat Leather boots --- never tried it myself but I can't see any reason not to try it.





All the best Mick

[crowbar]

A dollop of pig fat to soften pig skin ,it's natures way, just leave it in a pellet tin on a radiator for a week and when you size it -
it should be the filler washer that is sized to give the cup washer the correct fit.

Forgot to say- Put the Lard in the leather cup not the tin.

[crowbar]

You can buy leather cup washers for old garden pump up sprayers which tend to be thinner and more supple in various sizes and fit one inside the other to thicken them up .

[4end]

I am restoring an antique Mk1 Webley pistol. I have purchased an original looking leather washer, but it is as dry as a bone and rock hard.
What should I soak it in to restore its flexibility?
I am in England where gun supplies are hard to find. I see some other posts about appropriate lubricating oil. Would hydraulic oil or common machine oil be appropriate?

Neatsfoot oil is the traditional oil for lubing and softening leather washers, however, if you don't have any, olive oil is as good.

[TonyL]

Excellent information.. I'd never heard that before. Good to know. Have you tried it yourself?

The only thing is these days I only have one or two older HWs with leather seals (I'll find out for sure when I get round to opening them up) and I already have some neatsfoot on standby, so not many opportunities to experiment.

Now, a nice, old leather washered project gun would be handy.......

[SiegeA]

I came in to suggest neatsfoot too but it’s a firm favourite throughout the thread. As another consideration, and based upon my experience of making razor strops in the past, swarfega (green) is a good leather conditioner also. I’ve no experience of its effectiveness on leather seals, but thought I’d mention it. 👍🏽