KSC mags spray propane when filling

[LUTNIT]

I know this is an old topic as I found this when searching, but other than that, there was no where where the topic was being discussed. I just spent the last half hour searching this forum.

Anyway, my friends KSC G19 sprays propane everywhere when filling so its impossible to tell when its full. He was really worried about it but I knew it happened to KSC mags but had no idea how to fix it. Just got a KSC M93r (version 1) and it does the same but the thing is I cant get it to fill completly, never fires more than half the mag. Then I remembered I saw two guys with KSC glocks at a game once and when they filled their mags with propane it didnt spray. O-ring? Or something else?

[Greylocks]

Doctor's Corner? If you posted this there, I'm sure one of the experts would have a solution?

Add details; how is it filled (method), with what (can? propane adaptor?)
Were any of the solutions or tips in the Doctor's Corner tried?

[CDN_Stalker]

Maybe the nozzle on the adaptor has flared on you from use? Had that happen, got to the point where all the liquid propane went everywhere but in the mag. I disassembled, put the butt in an electric drill, spun the tip on a hard tempered steel block to reduce the size, has worked great since then. Happens when you have fussy mags that require you to press hard to get the propne inside, the soft brass eventually opens up to the point the gas doesn't want to bother going in the mag since there is resistance in that direction.

[Rico]

I have this problem with one of my KSC glock mags. All my other mags fill fine, but one sprays everywhere. However, it still fills and I don't notice a difference in shots fired so it doesnt really bother me.

[LUTNIT]

The thread I linked to was in doctors corner and someone told the guy that it was in the wrong section so I tried it here.

AI propane adapter (works perfectly in my KJW M92)
Mag inverted and propane adapter pressed down in it perfectly in line

The reason it wasnt getting a complete full was because I forgot it was a larger mag (38 rounds instead of my KJW 25 round mags) so I pulled it off too soon, fills the mag no problem just sprays propane everywhere while doing it.

[Gryphon]

This is normal for KSC magazines. All of mine have done it, just a poor design. The way you can tell they're full is they start spewing MORE propane out the fill valve. :roll:

I believe you're correct that an O-ring inside the fill valve will help rectify the problem. I just live with it, propane's cheap enough and the smell doesn't bother me.

[firemachine69]

Just make sure you're not around the oven when you fill it up! :shock:

[MMMiles!]

Originally Posted by Gryphon

This is normal for KSC magazines. All of mine have done it, just a poor design. The way you can tell they're full is they start spewing MORE propane out the fill valve. :roll:

I believe you're correct that an O-ring inside the fill valve will help rectify the problem. I just live with it, propane's cheap enough and the smell doesn't bother me.

MadMax can clear this up, but I beleive it's an overflow feature that prevents you from putting too much gas in your mag.

[CDN_Stalker]

I've noticed that too, sometimes I'll get a small leaking sound after filling, and it stops after a couple minutes. I've got 6 KSC mags for my G19 now, a couple have sprung leaks that I have either fixed with working oil in, one I replaced the square "O-Ring" in the base, another I used the gasket sealing stuff around the valve threads.............. all work great now. Once in awhile I'll over fill and get the slight leak sound.

Oh ya, make damn sure you keep some gas in the mags. Had more problems from storing empty than anything else.

[LUTNIT]

Hmmm......I'll try tossing in a small O-ring into the base and see if it stops the spray, now to just find some O-rings lying around the house...

[MadMax]

Gah, I had pretty much given up explaining why some mags normally vent gas while filling and why others didn't. However, it irks me when people confuse superior and inferior designs.

In my post, I will address normally functioning mags only. I am not going to get into the various points where leaks develop and how to fix them. The pictures to follow are kludged from a KSC G17 manual found online. Because I'm not Pshop savvy, I mangled them in MSPaint to communicate principles.

Ignore the fact that the mag cross section is shown in a GBB frame. You shouldn't be filling your mag with your gun in battery. Also imagine the mag oriented vertically instead of the 20ish degree from vertical orientation shown. MSPaint only allows me to rotate in increments of 90deg so I couldn't even turn the mag vertically.

On KJW and other Taiwanese mags which appear to seal to fill probes very well (i.e. little leaking while filling):

Lower cost magazines use a single port fill valve. During filling, the probe on your gas reservoir (say from a spanky new V4 propane adaptor) depresses the fill stem in the base of the mag. One passage opens up allowing liquid to flow through the centre of the fill tip and the fill stem. Gravity pulls liquid propellant to the fill tip in your propellant bottle and it pushes through the fill valve into your mag. Eventually pressure equalizes between the bottle and your mag and liquid transfer stops:




On KSC, TM, WA and other Japanese mags which audibly leak while filling and spurt liquid when full:

Japanese mags are a bit more complicated. If you take them apart, you'll note a brass tube attached to the mag base. These tubes also often have a smaller diameter tube inside them.

These tubes are not gratuitous material. They actually perform an important function.

The fill valves in Japanese magazines is a two port valve. Depressing the valve stem opens two passages! One passage opens through the centre of the stem. Another passage opens and allows flow AROUND the sides of the stem. Don't believe me? remove a fill valve from a Japanese mag and look for a very small hole drilled into the side of the valve close to the threads. This is the sideport which allows flow around the stem.

Why two ports?

While the TW mag only allows liquid transfer until pressure equalizes between mag and bottle, the sideport (I call it the relief port [RP]) allows gas to leak out of the magazine when the stem is depressed. This means that you will never equalize pressure in the mag with the bottle because the RP keeps letting gas leak out.



??!!WHY intentionally leak gas? I'm trying to fill the damn thing!

Farting a bit of gas allows you to keep accumulating liquid at the top (which is the bottom while the mag is inverted) of the mag and never equalize pressure with the bottle.

Liquid accumulates until the liquid level reaches the bottom of the tube integral to the mag base:



Eventually the liquid level touches the tip of the mag base tube (which I will call the Overflow Pipe [OP]). Because gas is being allowed to escape around the sides of the fill valve stem (through the RP), liquid propellant flows up the pipe instead of filling the space around the pipe. When the liquid propellant completely fills the pipe, it spurts out the relief port [RP] and that indicates a full mag.






The point of the leaky fill valve and the goofy OP is to ensure that a CONSISTANT dose of liquid propellant is transferred into the mag despite differences of initial temperature between the mag and the bottle. Furthermore, it ensures a certain amount of propellant
gas space around the OP. Expanded propellant is what propels your GBB. Unexpanded liquid does not evaporate quickly enough to properly action a GBB.


BS! Whatta load of hooey!

Try this with a functioning KJW and TM/WA/KSC magazine:

-start with empty mags and warm them in your pocket
-chill a bottle of propellant in your freezer for 1/2 hr
-fill each mag
-allow mags to stabilize to room temperature for 1 hr
-count off how many bbs a gas charge propels firing one pellet every 2 seconds (actually time this with a digital watch to keep things fair)

Record your results and repeat the experiment only, let the gas bottle stay outside in room temp

-freeze the mags for 1/2 hr.
-Fill the mags while they're cold
-allow mags to stabilize to room temp for 1hr
-repeat shot count test with 2second interval.


Other Applications this Pneumatic Arrangement is Used in:

If you ever disassemble a refillable butane powered mini torch you'll find the same arrangement of tubes and valve (well there's one in the Bernzomatic torch anyways). I'm not sure I've seen them used anywhere else, but the Japanese aren't the only ones concerned about keeping a certain amount of expanded gas in a two phased pressure reservoir.

[CDN_Stalker]

Ok, NOW I say sticky this thread! Thanks Carl, that was awesome!

[aZn_triXta07]

All hail 1337|\/|4573R C4RL