Anyone rebuild a welding regulator for kegging?

So, I just picked up a 64lb (what's that, an 'A'?) cylinder and a regulator for free (tank needs to be hydro'd).

The regulator leaks, though. I've taken it apart, and there are some cracks forming in the rubber membrane. I used some contact cement and glued 2 layers of 8 mil nitrile to the membrane, then lubed up all the seals and o-rings with silicone plumbers grease and reassembled it. It seems to work well now - is there any reason why I shouldn't use it?

Anyway, 64lbs of CO2 ought to last nearly forever, though the cylinder is so freakin huge I'll probably leave it out in the garage and plumb in a CO2 line to my beer room (which shares a wall with the garage)

Look for a rebuild kit. They're fairly simple to do. Make sure it's a PSI reg and not a flowmeter type.

make shure that it's a CO2 reg and not an O2 reg.

yeah, it's CO2, and it's a pressure regulator. My jury-rigged patch job seems to have worked - it's held pressure all night and not lost a single PSI (the tank valve is off).

I'll see if I can find a proper rebuild kit in the meantime.

It doesn't really matter what time of regulator it used to be as long as it wasn't something toxic but o2 would be fine. You just might need to change the fittings on it. I would really suggest that you go to your local welding supply and have the regulator professional rebuilt though. The rubber thing you talk about is the diaphragm. It is what does all the work. When you get holes in it, the outlet pressure will creep up to the point that it will be the same pressure as in the tank, so possible 800psi+. Most hoses and kegs cannot hold that amount. I would hate to see what would happen if a keg exploded in a fridge. Because of this I always suggest that regulators get rebuilt professionally. At the same time ask the welding ship how much it would cost to get the tanks hydro tested. Good score on the tanks, some of those go for $200 plus now a days. IF your wondering, I work for a welding supply so I have a good idea of the dangers.
As a side note to anyone, always and I mean always, turn your regulator adjustment knob all the way out when ever turning on the gas to a tank. An engineer for a regulator company once told me that the pressure coming out of a tank and hitting that diaphragm can be like 10,000psi plus when you first turn it on. This is the #1 reason diaphragms break.

hang on a sec - a hole in the diaphram leaks gas into the top of the regulator body, where there are vent holes, and the gas escapes. I don't see how that could lead to excess pressure unless those vent holes somehow got plugged up

Your right that is a fail safe, but you will also see a metal disc that is usually attached to the rubber diaphragm to disperse the load from the spring to the diaphragm. Sometimes leaks or holes occur there as well and get transfer to the outlet and not the vent holes. I do not repair regulators for a living, I send them out to get repaired, there is too much liability in repairing regulators. I have experienced both, outlet pressure creeping and gas going through the vent holes. Since I work with high pressure gas everyday I am a little more cautious then everyone else. I have just seen too may accident photos from the fire department with tanks, especially Co2. I just personally would trust my family's life on a rubber cement fix. I know it sounds extreme, but that is just me. If you feel that it will work go for it. I just wouldn't do it. I am just trying to give you a perspective from someone that deals with it for a living.

It doesn't really matter what time of regulator it used to be as long as it wasn't something toxic but o2 would be fine.

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a O2 reg's guts WILL NOT last long with the cold of CO2.

local welding supply

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will tell you this

the guts of an o2 and co2 are the same. Co2 is the same temperature as ambient unless you withdraw so much that the temps drop (similar to propane), which you shouldn't run into. If it were colder then you would see ice or frosting on the outside, there is no insulation properties with the tank. They do make special co2 regulators that have heaters in them for co2 but that is in extreme conditions. We swap regulator fittings all the time and they have adapters that let you use co2 for nitrogen and vis versa.

I have been welding and fitting sence before you were born, lets not get into a pissing match.

I am not trying to get into a pissing match either. I believe you when you say you have been welding and pipe fitting before I was born. I have been doing this for 14 years. here is a link to a service page for a common victor regulator. It does not have any different parts from the oxygen vs the co2 except for the cga fittings. I will gladly admit if I am wrong. But I still say they are the same regulators.

http://www.thermadyne.com/IM_Uploads/DocLib_2305_56-0610 SR 450 Series Regulator.pdf

I have rebuilt a number of regulators over the years, for both myself, and for welding use at work. I have swapped guts from one to another, though I wouldn't take a part from a non O2 regulator and put it into an O2 regulator. Same part numbers in the catalogue.

Without an adapter, you would have a hella time getting the CGA 540 fitting on the CGA 320 though.