Quad Rings

[Pointy]

Been doing some googling and came across Quad rings (AKA X-Rings). Anyone tried them? Thoughts?

http://www.mcmaster.com/#x-rings/=r2v0bh

Think #14 Viton (P/N 6540K124).

[lurkingknight]

they were all the rage a few years ago... some of the more hardcore builders on asm said they wore out a lot faster than a standard O-ring. Benefits/improvements seemed to be rather marginal when O-rings and X-rings were compared with similar setups and lubing.

Every now and then a discussion about them flares up over there, but there's a reason they aren't standardized in aeg builds.

[Kos-Mos]

Theses are very good for hydraulic systems, not so much for pneumatic.

Mostly because of the lubrication issue, and because theses are usually inserted a very fitted groves to be efficient.

The way the piston head works, it needs a very loose fit to expand with air pressure, and let the air enter the cylinder at return/pull cycle.

Really the only type of ring that would be better is V or cup rings. With a lip that acts as a check-valve on it's own. But then you would need a new piston head design.

[Pointy]

Originally Posted by Kos-Mos

The way the piston head works, it needs a very loose fit to expand with air pressure, and let the air enter the cylinder at return/pull cycle.

Couldn't the air be supplied via the nozzle during the return/pull cycle?

A little off topic - As I understand it the holes on a ported piston is what causes the o-ring to "expand" against the cylinder during compression, but I have noticed I get grease in the holes which impacts this. Am I over-greasing?

[cetane]

http://www.speedairsoft.com/ProductI...ist&category=6

I built a piston for my BA aps2 clone and used a q-ring on it. I still need to try to verify, but I am probably loosing a good bit of fps from the drag of the q-ring on the cylinder body.

Holes in piston head face more to let air into the chamber from gearbox side than to aid in expanding o-ring

[Kos-Mos]

Originally Posted by Pointy

Couldn't the air be supplied via the nozzle during the return/pull cycle?

A little off topic - As I understand it the holes on a ported piston is what causes the o-ring to "expand" against the cylinder during compression, but I have noticed I get grease in the holes which impacts this. Am I over-greasing?

Yes.
But they also serve as ports for the returning air to go through.
The nozzle hole is not enough on it's own to prevent too much suction.
That's why the gun can build pressure and fire, the hole is too small.

It's ok if there is grease in there. The air pressure will push it on the o-ring is lube is needed. Too much it not that good either, if there is a layer of grease on the face of the piston/cylinder, that's a bit much.

I barely put enough to lube the o-ring (usually I remove the o-ring, rub it between my fingers with grease and reinstall it).
Most of the time it's silicon oil, ultra heavy weight for RC cars differential tuning. It does not run.

[SuperHog]

quad rings will only work if the grooves for it has certain dimensions, same for o-rings. Sticking a quad ring onto a groove meant for oring won't work. It will be either too tight or too loose affecting air seal.

[ThunderCactus]

Also, the design of the grooves in piston heads is not optimized for use with quad rings.

They're really optimized for static and high pressure sealing, not fast dynamic pneumatic seals.
They'd work better as an unvented piston head.