KSC USP .45 Mag gas leak

[Hornet_Seven]

Hey guys, sorry but I'm a bit of a gas guns noob, seeing as this KSC USP .45 is my first gas powered gun.

A fortnight or so ago, my can of 134a gas had its nozzle broken off and I've only just gotten round to getting a new cannister.

Since the can got broken, both of my USP mags seem to have developed gas leaks One makes a hissing noise of escaping gas from the base (ie. where the gas goes in), whereas the other one makes both the aforementioned hissing from the base as well as a much louder hissing from the valve at the top (the one the gas goes through into the gun when the mag is in). As soon as gas goes in, it comes straight out the other end, pretty noisily. Just so you know, both the mags still had some gas in them 2 weeks ago (that much about gas guns I do know, musn't leave them empty).

Anyway, could somebody tell me what is wrong with my mags? If so, how ****ed are they and is there any way to fix 'em? I can't really use the correct terminology (don't know it yet :p) but if anybody can help me and needs some more clarification on the problem, let me know

EDIT: The first mag (the less broken one) has stopped hissing, I'm guessing it just needed some more gas to restore the seals, right?

[dope_on_a_rope]

Re: KSC USP .45 Mag gas leak

You could probably get away with just screwing up the valve at the top of the mag. If the 134a doesn't sort the leek from the bottom, take the bottom off. There's a couple of push pins, just hammer them through. You'll then find a large square o-ring, which is probably the culprit. Either leave it overnight in silicone or break fluid to swell up again, or paste it with gasket sealant, and reinsert it immediately. I've also seen people wrap the groove it sits in with PTFE tape, to reduce the space the o-ring has to fill.

[mrpugster]

Re: KSC USP .45 Mag gas leak

i've got 3 KS mags but never had a problem with the mags themselves just the gun is rubbish -), take them apart and soak the orings in white silicon grease overnight and replace and test...

[tisane]

Take out all the seals and the valves and soak in silicone oil overnight that should solve all of the seal issues, and free up the valves too.
If not then the valves will prob need replacing, and the seals use either ptfe tape or instant gasket.

[Hornet_Seven]

Re: KSC USP .45 Mag gas leak

Cheers guys, will get on it now :D

[Just an Airsofter]

Re: KSC USP .45 Mag gas leak

Several things

Leaks will be due to seals drying out, always keep gas in your mags to maintain pressure on the seals. If you leave mags empty they will dry out and leak.

You can rejuvenate seals by soaking them overnight in silicone oil, or in very bad cases Automatic transmission fluid, this attacks the seal and swells it up so don't leave in for too long.

The easiest way to stop small leaks is depress the valve on the back of the mag and squirt silicone into the port on the top of the valve. leave to soak into the seal and fill with gas. Repeat several times if they still leak.

if you take the mag apart smear the seals with silicone grease before re-assembly.
Please avoid silicone sealer, instant gasket or any other liquid sealer to prevent leaks, it's a bodge, will mean lots of extra work if the mag has to come apart again.

[dope_on_a_rope]

Re: KSC USP .45 Mag gas leak

Please avoid silicone sealer, instant gasket or any other liquid sealer to prevent leaks, it's a bodge, will mean lots of extra work if the mag has to come apart again.

Well, I've never had to take the base of a mags gas chamber off, for any reason other than a dry o-ring. So gasket sealant seems to make perfect sense to me. Not impossible to get it off, if you have to, I wouldn't have thought.

[tisane]

Re: KSC USP .45 Mag gas leak

Theres nothing wrong with instant gasket, most fixes tried on mags could be called "bodge jobs" as with the exeption of replacing the seals/valves completley nothing can give a 100% certain fix.
As has been said if it doesnt work then it is easily removed and another method can be tried.

[Just an Airsofter]

Re: KSC USP .45 Mag gas leak

Theres nothing wrong with instant gasket, most fixes tried on mags could be called "bodge jobs" as with the exeption of replacing the seals/valves completley nothing can give a 100% certain fix.
As has been said if it doesnt work then it is easily removed and another method can be tried.

it's a bodge, pure and simple. gas mags don't come with instant gasket in them, they have seals that if properly maintained will bridge the gap indeffinately. Instant gasket does not have the same qualities as seals, it shrinks and is not designed for a sealing area that is mobile (as are most joins on airsoft mags). any gasket compound also has a nasty habit of spilling out under pressure as it is assembled, this spilled sealant can't be seen as it is inside your mag. It then breaks away and finds it's way into the value and working components of your gun. This is the main reason gasket compound isn't used.

By suggesting people use sealants rather than proper seals you are risking them causing further issues and problems with their guns.

The 2 reasons mags leak are the seals are damaged or they have shrunk.

Damaged seals need replacing, seals that shrink can be replaced or re energised by soaking in silicone.

The application of a good quality silicone grease to the seal will keep the seal lubricated and in good condition.

[tisane]

We are talking thin smears here not bloody making new gaskets out of the stuff!!
A little common sense is all thats needed.
Yes it may well come out of the joints too if it isnt left to cure properly.
As i said its ADVICE if people reading this dont want to take it then thats fine, there are several ways of trying to reseal mags, and we may not agree with them all, but at the end of the day its down to the person doing the repair what they want to try first.
Ive used it a few times both for myself and other players on site and have never had a problem so dont see a problem with reccomending it to other players.

[dope_on_a_rope]

Re: KSC USP .45 Mag gas leak

Stay calm guys. I'll lock this thread if I have to. The original question has been answered, with different opinions, but both are backed up with reason. That's fine.

I've repaired a fair few mags with gasket sealant. Personally never had any problems with it. The problems you described above don't sound unbelievable, but even so, for the price they charge for a new set of seals, against the price of a 20th of a tube of £4 gasket sealant, I'm quite happy with my bodge job. If the OP wants to do things properly, by all means buy the new seals - if revitalizing them with break fluid or silicone hasn't worked.

[tisane]

My fault.
I apologise.