I must confess to a soft spot for the phosphor-bronze piston rings in some webley and FWB guns. They feel 'future-proofed' to me.
I know we have made progress with better seals but I find the best seals to have in a vintage gun is the original leather. They just seem to hold up forever, that’s worth more than a few extra FPS. I’ve been extremely lucky to recently purchase some great old vintage guns. All I’m sure with their original leather seals. Weather warmed up to take my BSA Airsporter MK2 out and give it a go. Guns well over 50 years old just put some SAE 30 ND in when I got it. It’s shooting 550+ still right on original specs. Bought a 1930s Tell 2, still shooting fine after 70 years. I’ve purchased 5 Haenel 28s in the last 2 years, all never needed anything but some oil. Two Webley Straight grips one 90 years old same story. I have a FWB 65 with a modern material stop I had to replace, the original just crumbled out. I know leather can wear out but I just don’t see age being much of an enemy. Don’t have that comfidence with the seal in my Beeman R1?
I must confess to a soft spot for the phosphor-bronze piston rings in some webley and FWB guns. They feel 'future-proofed' to me.
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I like them but when manufacturers ditched leather and 'O' rings and took up nylon parachute seals like the Feinwerkbau Sport had been wearing since the early 70s power went up 25% and the running-in time dropped to a tin of pellets instead of 20,000.....
I think if you are careful with fitting them and don't go too mad on the sizing they will last for several years. The Feinwerkbau Sport ones will definitely turn into cheese after 10 years. So, no, they are definitely not as durable or forgiving as leather but they are far more efficient and they are not much money to replace when the time comes. A leather seal can be forced past razor-sharp edges, endure heavy dieselling, seal an out-of-round cylinder and last for decades on no lube (provided the seal has been well lubed at the beginning of its life) and can be replaced with a substitute cut from an old belt, so they have advantages. If they go hard and dry they can also be refurbished with a roughing up with a file and a soak in oil overnight. The smell of a leather-washered springer that is 'on song' and combusting oil at the right rate is delicious!
Last edited by Hsing-ee; 13-02-2018 at 01:02 AM.
I converted my Webley Vulcan to a leather seal over thirty years ago; it's still on the same one, and is smooth and very consistent. My Ospreys are similarly converted.
As Hsing-ee says, leather is very tolerant of cylinder wall irregularity, but they need to be sized to a good fit. Usually a relatively loose fit works best, it should be very easy to push it down the cylinder. Too tight will rob it of power.
Old type polyurethanes suffer from microbial degradation and basically disintegrate over a long period time. Some polyurethanes suffer from hydrolysis. Fortunately the new polyurethanes have additives to prevent this and will last far longer than the owner of the gun.
Baz
https://polymer-additives.specialche...n-polyurethane
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It’s been interesting for me going back in time with my vintage airgun purchases. I’ve been fortunate to buy some old but virtually new guns. It’s like a time machine seeing what it was like to airgun in 1959? Yesterday it was finally warm enough to take out my BSA Airsporter MK2. The lubricated leather seal gave me 575 fps with a 14.5 grain pellet for 10.5 FP. Did some close target shots, so nice. Yes we have “progressed” to more powerful rifles but I could care less? Do I really need more power? What is amazing to me is that with this technology and craftsmanship a Airgun made it 55 years with no degradation. My Beeman R1 couldn’t make it 15 years without losted performance.
Yes ... I see nothing wrong with the old leather seals and it somehow feels wrong to replace an original leather seal in a vintage gun with a modern plastic seal. But I have known leather seals to fail with age; but they are easy to make and replace, which all adds to the enjoyment. However, a quirk I am very aware of is that an old leather seal that falls apart on stripping the rifle and thus needs to be replaced can often be doing a very good job before the strip.
Cheers, Phil
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Interesting point. When I started work in polyurethanes in 1994 we were already using additives. There are two types of urethane, polyester and polyether. I think the polyester is more susceptible to bacteria attack. I have Weihrauch seals out of rifles over 20 years old and they are fully functional in good condition. It is difficult to know what material each manufacturer is using without asking for specs. I would think that all manufacturers use modified resistant polymers now.
Baz
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD
Over the years I have acquired a number of Webley mk3's, two of which I had as a lad in the late 1950's. It was then I replaced the leather piston washers on both and they were used for a number of years before being stored and since then have had little use. Both will still hold air in the standard compression test (by cocking, raising loading tap and releasing trigger while holding cocking lever), no air leaking either past the tap or the washer. After almost 60 years both rifles have the same power as they did then.
On the other hand the polyurethane washer I replaced on my Original model 5 pistol four or five years ago has disintegrated AGAIN!
In terms of longevity it seems leather beats polyurethane hands down.