Is there an alternative to o-rings?

As long as aluminium / metal in use, there will be these rubber o-rings.

Maybe DLP 3D printed parts could be an answer, again depending on the resin used to create various parts. But such setups will results in much higher costs for low volume production.
But even then there will be some o-rings used.

The big difficulties with 'O' rings are:
The actual removal and fitting (and its usually the smaller ones that need replacing).
Selecting the EXACT replacement ('near enough' wont do).

I speak as someone with many FX rifles !

The problem for those in the Americas seems to be getting hold of Metric sized 'O' rings.

Could I take this opportunity to point out that most 'O' rings are seals not washers - they are not supposed to be overtightened (over compressed by tightening), hand tight is normally correct.

I would like to know if anybody has the O Ring sizes commonly used in the 2 following rifles.

Ruger Blackhawk Elite (which is a Umarex Octane I think)

Crosman Nitro Venom Dusk .22

I would also like to know if there is an upgraded piston seal for the Crosman Nitro Venom Dusk 22?

Hi Michael
If some o-ring, it gives you many problems, you can replace for one HNBR O-ring it's more resistant but there are less sizes.

Best regards
Enkey

I think I have a large assortment of HNBR O Rings from Harbor Freight.....

I know for a fact that I have a regular butyl assortment. Do these models use standard or metric sizes?

There are a number of alternatives to using o-rings to seal high pressure fluids. However, most make a permanent assembly as these are mostly glues, and welds. Rubber (many different kinds) is really about the best and least expensive way to make a seal since it expands to fill the space and becomes tighter as pressure is applied.

There are thin metal seals that are usually made in a cup shape that expands, much like the skirt on a pellet. One of the problems with the metal cups is that they can corrode where differing metals meet or weld if similar. 

Piston rings are another type of metal seal that work with a little bit of oil. However, over time and under high pressure, the oil will eventually be pressed out and then begins the slow leak. In the case of a spring piston airgun, however, this method may work quite well, but may require adding oil periodically or the use of a permanent dry lubricant.

My biggest frustration with air gun O-rings is the fact that most gun manufacturers seem to go out of their way to use odd ball, hard to find sizes. If they would just use standard sizes it wouldn't be that big of a deal.

Hi Bob

Use standard inch and standard metric.

Hi Rocko

The problem is if made EU 90% is metric size and if made USA or England is inch size.

Best regards
Enkey

I've delt with Oringsandmore.com and they have or will get just about any metric oring you need. Great people to deal with. 

Like many here I have had my issues with O-rings. I got half too smart one time and elected to go with a much higher durometer material for a tougher O-ring. Only problem was the ring did not have enough give to install and proved to be a small waste of money and time. I think were stuck with them. Only thing you can hope for is better designs from the manufacturer. My biggest issue is getting them past the hole in the air tube where the pressure gauge block sits. Its a real ring clipper.

Using the proper material for the job is key. NBR orings work good just use the proper durometer. Many times if the oring is not moVing and you have problems the durometer could be too soft and the oring is pushing out. If the part is moving you might try polyurethane orings as they are more abrasion resistant. Look at what the oring is being used for and pick a better material suited to the application most just use NBR as they are cheap a 4 cent NBR could be 45 cents in another better material. They are cheap so it is easy to experiment.

It took me forever to track down the correct material and for the fill probe on my Hatsan 44 which I was destroying regularly.
Posted information somewhere on one or more site(s) and now have no idea the size , thought they were available from McMaster Carr or MSC,but now I can not remeber which.

I had started to post a while back, that a sticky some place with model and O ring sizes/materials would be great.

So far the fill probes are the only O rings I have had fail, but bound to have a leaker one of these days, or just change out all O rings on a routine basis. I have no idea of the average lifespan.

Lifespan of O ring is also likely dependent on the material it is made from.

Ridin just measure the one you have measure the thickness or cross section and measure the Internal diameter. You can also measure the piece that the oring sits in. Then look it up to see if it commonly available most are. I only have a couple that I have had to special.order. sounds like you need a polyurethane oring or a harder durometer for your application.

AZBOBCAT
I'm thinking the durometer for the replacement is 75.

Issue I had measuring OD, ID and thickness was guessing when I had the measurement without distorting the O ring.
Several companies use a probe that I have always assumed were the same (yes, I know about assume)

See if such things were just posted . . .

Or better yet if all fill systems used Foster fitting

Michael , I have worked as an aircraft maintenance technician for airlines and now corporate jets and all fluids and gases that keep them operating will leak at some time just like our guns. No alternatives in site. The many types of "O" ring materials vary from the components they seal. It would be nice if I had some size charts to cross reference our gun seals into higher quality aircraft seals.