Umarex How to make CO2 seals for Walther PPK/S bb gun- updated

[Bluemill]

The CO2 seals that come with the the gun just don't last and Umarex has never sold them. They used to sell the air valve which included the seal, but they are not selling parts anymore. With the advice of Member "Nervoustrig" I got the tools, leather punches in mm's, and the sheet polyurethane in 2mm thickness and 80 durometer to make new seals.
I have 2 PPK bb guns now, a 2014 first series, and an early second series with the flush CO2 tightener, sold to me kindly by member TWebster. (WHAT A GREAT SITE! ) Recently, I've had difficulty getting a new CO2 cartridge in EITHER gun, going through 6 cartridges, hissing and freezing with horrible leaks on attempting to install them. I tried several different size combinations, most of which failed.

My problem was that I was trying to replicate the measurements of the OEM seals, thinking I'd get better performance that way- NOPE! the originals have a 4mm hole, and I'd judge the polyurethane to be much softer. The SIZES that work best for me is an 8mm outer diameter seal with a 3mm hole in the middle to allow the puncture point to come through. A seal with a 2.5mm hole is one of the guns now holding gas, but it took a lot of screwing down to get it to stop leaking, while the other gun was virtually silent after puncture and made an authoritative POP on first trigger pull! How long the 3mm hole one will last remains to be seen, but at least it is working well now.

Bluemill
9/14/23

 

[Northwoods22]

Good information. I've got an early Umarex PPK that surprisingly still doesn't leak. It will sooner or later though so I'm filing your tool and material info away for future use.

 

[marflow 777]

after spending two days looking for these seals i have found some but not close
do you have the part number that Umarex uses, there has to be more than just this gun that uses this seal
and seeing that the ease of finding the seal is near impossible making them looks to be the way to go

 

[Bluemill]

Umarex never sold the seals for either the 1999 or 2016 versions of the PPK/S, only the airvalve, which was cheap enough something like $12-15. About the time of the series 2 pistol they started to put punch marks on either side of the brass collar that holds the CO2 gasket in. I made a simple but effective tool to remove the collar that works great. Take a penny and hack saw about 15-20% of one side off. Then use some small vice grip plyers and carefully unscrew the collar, making sure you keep the tool in those notches of the collar. Once out and after making your gasket getting the collar back in is a challenge but it can be done. This is because the damage to the threads as a result of the punch marks. You have to persuade the collar back in, pushing it straight down then looking at to make sure it looks to parallel to the top of the valve. Remember the collar is brass and not that hard, so it would be easy to cross thread it!

The polyurethane I've used is 2mm thick and 80 durometer. I got the 1 ft. sq sheet from Fix it Supply from Buffalo, NY. Then I got the round leather punches from Amazon. The best size is 8mm OD, with a 3mm center hole. Whacking that punch through the polyurethane can be a challenge as it is quite hard and resilient. Ultimately, I held the punch in place vertically with a good sized pair of channel lock plyers to keep me from hitting my wrist or fingers. You really have to hit it hard to get through. Getting the small hole done is easier but be careful to get it in the middle. Good luck!

Bluemill

 

[marflow 777]

it is the same thing i did to make a the seal for the stem on the S&W 78g
the centering method i used was to get a wood dowel the size of the OD punch and then drill the center and insert a drill end and the dowel will is short enough to slide up and out of the way as you punch the OD size
so with that you can punch the small hole and you are centered for the OD and the dowel just slides out of the way
just an idea

 

[Bluemill]

Great idea, as I have been dead reckoning it with not perfect results! I've also had a thought about using this very small mini hand drill and pin point the center that way, but I think your idea is better.

Bluemill

 

[marflow 777]

punching urethane is not perfect anyway but it works and that is what counts and normally the leather punches are rather dull and they need to be chucked up and sharpened

 

[Bluemill]

In order to save the edges on my punches I put an old GOLF magazine under the Poly sheet to keep the punch from hitting the Masonite top of my workbench. I probably should try to sharpen that 8mm punch as it has done a lot of work of late.
Do you think that 80 durometer is the right hardness and /or what do you use, and how many cartridges can you load successfully before you have to put in a new seal?