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Old 10-09-2010, 06:55 AM   #1 (permalink)
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12g seals .. is it really that difficult?

So, it's late, my mind wanders and I come to thinkng of 12g seals and how generally problematic they are in Paintball.
So I ask this of the crowd ... how is it that we have pellet guns that have seals that last literally decades ... ???
Since the source of propellant is the same (CO2) and the container for said propellant is the same ...
Why is it that we are constantly battling the 12g seal fgailure? What is that magical substance the use for pelet/BB guns?

My Umarex/Walther CP99's (.177cal pistols) use a CO2 'magazine' and the seals for those never seam to wear out. They are a red rubber stuff but what they are exactly I don't know. They are considerably softer than urethane Pb seals though, I know that much.

Is it entirely possible that in our quest for reliable sealing we went to far on the hardness scale? There is mention of liquid silicone ... again softer than most traditional seals.

I'm tempted to get some Permatex hi-temp gasket maker and pour a sheet of it to cut custom seals from ... it's red, close enough? Seems to work for some of the liquid silicone parties.
Anyone have a clue what the magical last forever pellet gun seals are made out of?
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Old 10-09-2010, 08:16 AM   #2 (permalink)
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I believe those "ever-seals" are like the same material that Sheridan guns use, and some Palmers guns too. Probably something to do with how a shoot-to-pierce system functions. I don't see why you could not just order some from said companies and use an adhesive to secure them in a CCI bucket changers Insta-pierce setup. I used a small black oring from work and Krazy Glued it into my gargoyle's insta-pierce and it works the balls! Just clean the pierce cup with a Q-tip and rubbing alcohol (to remove any oils), apply glue in bottom of cup, insert seal, and install an empty 12 gram (tightly) for a day or two and presto!
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Old 10-09-2010, 09:46 AM   #3 (permalink)
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It is not difficult. For me, the 12g seals are not "problematic in paintball", because I have replaced them for custom made die-cut seals from PTFE (Teflon) plate, when I have problems with the original seals. They have costed me less than .20 USD per piece and they should last for ever.



It works in shot-to-pierce system (my PGP/ZGP/P68SC) or in insta-pierce (my BE Q-changer and PGP/P68SC rebuild for insta-pierce) - there is no difference.

The "problem" is that for the today manufacturers it is easier make seals from common soft seal materials than from PTFE.

The same material can be used even for cupseals and they will have the same (nearly unlimited) lifetime.

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Old 10-09-2010, 01:23 PM   #4 (permalink)
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Air gun seals last forever because they aren't used like a paintball gun. You end up gassing it up, going out on the porch and shooting a couple shots at a stump in the back yard then putting it back away in it's case. No putting 20+ cartridges thru it in a few hours. No rolling around in the dirt. No rapid firing to continuously freeze the 12 gram to the face of the seal.
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Old 10-09-2010, 04:31 PM   #5 (permalink)
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Quote:
Originally Posted by Usurper View Post
Air gun seals last forever because they aren't used like a paintball gun. You end up gassing it up, going out on the porch and shooting a couple shots at a stump in the back yard then putting it back away in it's case. No putting 20+ cartridges thru it in a few hours. No rolling around in the dirt. No rapid firing to continuously freeze the 12 gram to the face of the seal.
That sounds rationally, and you have partially true, but the reallity is a little more complycated - the different way how are the airguns used is not the only factor here. Some match arguns for some disciplynes ("Air Pistol 60" for example) are typically under pressure for one hour and then they are degassed, some use few powerlets in hour ("10m rapid fire air pistol", for example). That is fully comparable stress with the stock class markers.

And every common seal material needs be replaced after few (5-7) years because of the natural material ageing - it does not matter whether or not was the marker/airgun used. Oil layer, thickness of seal, specific density and chemical composition can slow this degeneration effect but not stop him.

Only fluoroplastic seal materials - Viton and Teflon - have unlimited lifetime because they do not interact with other chemical elements.

Harder seals have limited usability, but they tend to be more durabile in time. So even when you use common Nitril-Butadien-Rubber, there will be difference when you use 70 Sh or 90 Sh hardness.

Good solved longitudinal seals / thrust plain seals are commonly more durable than radial seals and common o-rings.

Some airguns have only few seals (3 including of the chamber seal, for example) and these are solved like longitudinal seals and made from quite hard materials or from fluoroplastics, so they can be functional even when they are gassed for years.

Last edited by 3022; 10-09-2010 at 04:49 PM.
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Old 10-09-2010, 05:21 PM   #6 (permalink)
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Imho softer seals are really better. Harder seals tend to be little problematic sometimes, and the reliability in different conditions is imho more important than the lifetime.

Imho the temperature of the material (which affecting the elasticity of the material) can be only part of the problem - in cold the pressure in CO2 gun is lower, so the seal is not so pushed to the sealing face. And with harder = less elastic material you need more force to seal.

Harder seals are imho good especially for difficult accessible parts whitch are closed in metal case and are not often pressed/released (o-rings around old style Sheridan valve for example).
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Old 10-09-2010, 05:41 PM   #7 (permalink)
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True about the lifetime of both viton and teflon, but being in an industry that uses both of these materials on a regular basis, I have seen them both fail over time. Unfortunatly my experiance has only been how they fail when steam is introduced, and it does take years and years in that case for them to fail, if ever. Like CJ said the trouble for myself with the harder materials is the frost/freezing factor, I should try to grab some class VI EPDM gasket material and see how it holds up, it could just be chemical resistant but it seems pretty touch physically as well. Any way to the OP its seems like your best bet is to try a ton of things and see what works best for you with what is readily available. Good luck in any case.
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