DIY - Fix leaking GBB mags. (with pictures - 56k beware!)

[lemegacool]

Originally Posted by 13Fido13

The extra air from taking the fill valve out would help, but to be safe you should leave it for a week or so.

It's better to wait a bit longer then have to do it twice and wait the extra time.

if you got a valve key, removing the output valve is also a good idea!

[Azathoth]

Option B. Take a line of the gasket sealer and let it partially congeal and seal before closing the mag up. ?? not having any problems with this so far.

[aznpos531]

I guess I got lucky! I only let the gasket cure for 24 hours before I gassed it up and it's still holding nicely.

[DonP]

This last post brings up a good point. While I discovered that 24 hours is not enough to fully cure the stuff in a mag, that doesn't mean that the goop actually needs to be fully cured in order to work...

Since many people have had good results with the reduced time, clearly a 100% cure is not required to get serviceable results. Probably there is a "sweet spot" in there somewhere.

[13Fido13]

With silicone products that we use in the shop, you find that they start to harden in a few hours. Obviously as stated the more air they get the better it is for hardening.

Also I've found that just getting the seal out and cleaning it up along with all the other sealing surfaces can do wonders. The silicone just gives it another something to block the potential leaks that would arise.

[Ayashifx55]

awsome guide coachster, even though i don't have a GBB , ill show this to my friend. Your great ! Hope you'll do a GBBR mag fix one day

[CDN_Stalker]

I've only had one mag not work from leaving it for 24hrs, one of my KSC MK23 mags. I've done all my KJW M700 mags, about five of my nine KSC G19 mags, all worked fine after 24hrs, one (the one I learned to let it set for minimum 24hrs) I left for maybe 6-8 hours and filled it, didn't leak then test fired it, totally gummed up the entire inside of my G19, including all kinds of rubbery foam right down the barrel. And I've fixed a half dozen KSC USP mags without issues (Korv, if you are reading this, I say again, KEEP GAS IN YOUR MAGS ALL THE TIME!!! Mind you, I don't mind charging you $10 per mag for 10mins work each. :P~)

[echo2]

Ill will try this now thanks guys

[DarkAngel]

Remove the valves to allow air to get into the mag while its curing then.

These seem great for two peice mags, TM 226 Two piece mags this may not work for however, as often the issue is either "too many rounds force the two peices apart", fill valve leaking and output valves leaking as well. This stuff work for Hi capa fill valves?

[SGT_Blaster]

Thank you very munch for this post fix my mag yesterday try today everything work perfect thank again

[Reckless]

woot! fix a mag .. and unlawfully crack a cable box all in one thread... sweet!


BTW on the silicone gasket stuff... it's not really supposed to be fully completely cured to seal. consider that the stuff is made for valve covers, diff covers .. etc however Propane also has corrosive properties so give it as much time as you can stand to cure and stand up to the propane

[jonney.]

Sweet let mine sit and dry for about 4 days, and it worked like a charm!!

[thpethalK]

Originally Posted by jonney.

Sweet let mine sit and dry for about 4 days, and it worked like a charm!!

How can you go 4 days without firing your GBB???? I can't stand not shooting something at least once a day...

[jonney.]

Well I have 8 other mags so I just used those well it was drying.

[coach]

Update:

I had to redo 2 of 4 TM mk23 socom and 1 WE p14 mag. Not sure why or how they developed a small leak.

I had a few Well G55 (mp5k) mags and could not fix their inherent output valve leaks. Even with new high flow valves, I could not get them to hold gas properly. It's possible that the valves were not 100% to spec and or the mags are made inconsistently. 1 of 3 mags held gas over night with the original flow valve. None of the 3 held gas when I got them. 2 were brand new in the packaging but the main seal likely dried beyond rehydrating with silicone.

This week I worked on a SCAR GBBR mag. Original owner forgot to store them with gas, over the entire winter. Standard silly oil bath did not work. Took a lot more sealant to seal it up than an average GBB mag. I usually squeeze a 1 inch length of sealant on my work surface and it's typically enough to do 2-3 GBB mags. I ended up using a little more than 2x 1 inch lengths. All I did was apply it around the entire channel the rubber ring sits in and then spread more over it.

---------------------------

Originally Posted by Drake

So once everything is cured, the floorplate is basically "glued" into the mag? Or does that stuff separate easily?

Update:

No, the floor plate is not essentially glued to the mag. it will separate with some effort but not difficult at all. I had to use a small jewellers flat head screwdriver to pry/coax the floor plate to release but it wasn't so hard that it caused any damage to the mag itself. Only thing you need to be careful with is that you clean out every little bit of old sealant as the bits will end up getting stuck in your GBB. I went as far as to wash them with mild soap and water.

I'm going to add that before sealing your mag, to wash it with a mild soap to eliminate all signs of silicon oil. I have a theory that too much oil causes the sealant not to stay put too well so I will do this from now on. **Once it cures, please do remember to add silicon oil back into the mag via your gas fills. You will still need it for your fill and flow valves plus to lubricate your GBB.