# Pipe dope for regulator



## Stacy1 (Dec 15, 2016)

https://imgur.com/8YPW6HM


Went shopping for some pipe dope to attach my cga-320 to regulator and from reading posts here, was looking for some that contained Teflon. It was home depot and I couldnt find any, but I explained to one of the employees what I needed it for and he sent me home with this. I dont want to apply it until I know for sure that it will work. After reading the label once I got home, it states that its for gas, or water with a working temp of -45 to 120 degrees. The thing that concerns me though, is the maximum working pressure. Its 125psi. My co2 tank will be pushing between 800-900psi. Have I bought the wrong thing?


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## jeffkrol (Jun 5, 2013)

no that's good stuff..
W/ NPT most of the sealing is via threads anyways..
Used that stuff on 2 regulator builds (to be fair one had a flange fitting on the CGA so no dope needed anyways.)

BTW: No tape or sealent on the nut/treads that attach the reg. to the tank.. This is a surface to surface seal w/ the gasket..and use plastic/nylon or teflon gaskets.. Not the crummy paper type..And tighten good..
https://weldingsupply.com/cgi-bin/einstein.pl?PNUM::1:UNDEF:X:CO-6


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## Stacy1 (Dec 15, 2016)

Thanks so much for the fast reply


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## kevmo911 (Sep 24, 2010)

Dope is too messy for my taste, though some others use it. But that's the stuff I tried, and it worked. However, I've seen reports of it being blown out of threads at high pressure connections - the CGA nipple and high pressure gauge.


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## Dman911 (Nov 24, 2016)

kevmo911 said:


> Dope is too messy for my taste, though some others use it. But that's the stuff I tried, and it worked. However, I've seen reports of it being blown out of threads at high pressure connections - the CGA nipple and high pressure gauge.


I agree.

I have worked with pneumatics most of my life and I found that the tape work better for pressurized air systems and the dope works better for liquid or plumbing applications. As stated compression fittings and fittings with gaskets should never have tape or dope on them. Also they should only be used on pipe thread as its tapered and that what causes it to seal. Another reason ppl think that dope works better for pneumatics is because they use to much tape and when you thread it on it will just push all the tape back instead of sealing in the threads. 2-3 wraps is all that's needed anymore will not help.

Just my 2 cents and some useless facts/experience

Dan


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## Stacy1 (Dec 15, 2016)

Ok, so are you guys saying it is ok to use the tape on the cga-320 on the threads that connect it to the regulator body? I thought I had read to mever use tape on the high pressure side because of concerns of the possibility of getting tape pieces into the regulator? I tried the dope last night and must have not let it cure long enough. I plugged the low pressure side as my post body parts haven't arrived yet, and connected the reg to my tank to do the regulator leak test. I bought the regulator used so want to get the test done asap even though the seller guaranteed its been tested already. It leaked so much around the cga-320 that I could actually feel the gas blowing by the threads. I took it off, cleaned the threads on the connector and in the body and applied the dope again and its been curing since last night. I figured id give it a full 24hrs before I try it again. It states on the tube that the max working pressure is 125psi, and that has me concerned but if it's been used and does work then hopefully a longer cure time will fix the problem. If not, and its ok to use the tape, then thats what I'll plan on next. Otherwise its back to the store for a better dope


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## Dman911 (Nov 24, 2016)

Stacy1 said:


> Ok, so are you guys saying it is ok to use the tape on the cga-320 on the threads that connect it to the regulator body? I thought I had read to mever use tape on the high pressure side because of concerns of the possibility of getting tape pieces into the regulator? I tried the dope last night and must have not let it cure long enough. I plugged the low pressure side as my post body parts haven't arrived yet, and connected the reg to my tank to do the regulator leak test. I bought the regulator used so want to get the test done asap even though the seller guaranteed its been tested already. It leaked so much around the cga-320 that I could actually feel the gas blowing by the threads. I took it off, cleaned the threads on the connector and in the body and applied the dope again and its been curing since last night. I figured id give it a full 24hrs before I try it again. It states on the tube that the max working pressure is 125psi, and that has me concerned but if it's been used and does work then hopefully a longer cure time will fix the problem. If not, and its ok to use the tape, then thats what I'll plan on next. Otherwise its back to the store for a better dope


It should never be blowing hard from the CGA 320 connector or at all for that matter. I would say you are missing or have the wrong gasket installed unless you didn't tighten it (which I highly doubt). The connection to the valve on the tank from the regulator should not have and tape or dope on it. The tape or dope is only used on pipe thread (eg. not CGA-320). Can you post pics of the connectors at the regulator and tank valve showing the inside if the connections.

The only other thing I can think of besides a gasket is if the regulator has a blown diaphragm but that would not be leaking out of the threads.

Dan


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## Stacy1 (Dec 15, 2016)

Maybe I'm not wording things right. Its not leaking where the nut connects to the co2 tank. It's leaking where the nipple connects tothe regulator


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## jeffkrol (Jun 5, 2013)

kevmo911 said:


> Dope is too messy for my taste, though some others use it. But that's the stuff I tried, and it worked. However, I've seen reports of it being blown out of threads at high pressure connections - the CGA nipple and high pressure gauge.


Then is was never tightened correctly in the first place.. or damaged/deformed threads..


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## Stacy1 (Dec 15, 2016)

https://imgur.com/zghnzAQ

So this piece shouldnt have dope or tape?


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## Dman911 (Nov 24, 2016)

Stacy1 said:


> Maybe I'm not wording things right. Its not leaking where the nut connects to the co2 tank. It's leaking where the nipple connects tothe regulator


Ok try this... take the nipple out and replace the dope and screw into the regulator only as tight as you can make it by hand (but tighten as much as you can). then turn open the tank and see how much air is leaking. Then using a pipe wrench or channel locks etc. start to tighten the nipple into the regulator. If it start leaking more or doesn't change I would have to say its bad news and you have probably overtightened and cracked the housing previously. I'm thinking this may be the case and not much you can do to fix it. You can confirm this by tightening the nipple and looking with a flashlight at the regulator housing right next to the pipe for a small crack. You probably wont see it unless the nipple is tightened into the housing.

Added: Or as Jeff stated the threads could be damaged or cross threaded at some point. This would cause your issue as well 

Dan


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## Dman911 (Nov 24, 2016)

jeffkrol said:


> Then is was never tightened correctly in the first place.. or damaged/deformed threads..


Agreed both will work I just find the tape will hold up longer and better under certain conditions but that won't make a difference in the aquarium application. Just a personal preference.

Dan


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## Stacy1 (Dec 15, 2016)

https://imgur.com/Lk9NFm6.

Ok. Ive had the nipple installed into the regulator and curing since last night. Before loosening it and doing as you suggested, I hooked it up to the tank just to see if it was still leaking since taking it apart and re applying the dope. Its only been a few minutes but so far its holding 850psi. Yesterday when I tried it the pressure immediately started falling as soon as I turned off the tank. I guess I'll know for sure within the next six hrs. Thanks for all the help. If it loses pressure again I'll try what you suggested


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## Dman911 (Nov 24, 2016)

Stacy1 said:


> https://imgur.com/Lk9NFm6.
> 
> Ok. Ive had the nipple installed into the regulator and curing since last night. Before loosening it and doing as you suggested, I hooked it up to the tank just to see if it was still leaking since taking it apart and re applying the dope. Its only been a few minutes but so far its holding 850psi. Yesterday when I tried it the pressure immediately started falling as soon as I turned off the tank. I guess I'll know for sure within the next six hrs. Thanks for all the help. If it loses pressure again I'll try what you suggested


Pipe dope won't cure but will degrade and dry out over time. If its good now then I would assume it may not have been tightened enough or cross threaded and you got a bit lucky when reinstalling it. Good to hear its fixed and hope all goes well

Dan


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## Stacy1 (Dec 15, 2016)

I must have not had it tightened enough. I cleaned all the threads and it didnt look to have any thread damage though I cant be 100% sure. I hope it holds. I'm kind of wishingI had just went with the tape after rreading this thread. I didnt think you were supposed to though. Oh well. Still holding


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## Dman911 (Nov 24, 2016)

Stacy1 said:


> I must have not had it tightened enough. I cleaned all the threads and it didnt look to have any thread damage though I cant be 100% sure. I hope it holds. I'm kind of wishingI had just went with the tape after rreading this thread. I didnt think you were supposed to though. Oh well. Still holding


Tape or dope will both work. I just prefer tape for ease of use and longer life in the elements (which wouldn't be an issue in the aquarium world).

Dan


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## jeffkrol (Jun 5, 2013)

Stacy1 said:


> I'm kind of wishing I had just went with the tape after rreading this thread. I didnt think you were supposed to though. Oh well. Still holding


General opinion is that teflon tape "pieces" can make their way into the reg. innards..
IF this is really an issue is a bit debatable..

Thinking back a bit don't believe any new regs had either.. 
Pipe fitting is kind of an art.. Like when you think it is tight enough.. tighten another 1/4 turn..



> Oxy fittings get a special tape or dope that is oxygen safe on the tapered threads. It is NOT standard teflon tape. Other gasses arn't so critical, but you want to be REAL careful, because if you get even a tiny bit of tape into the regulator, it WILL cause problems somewhere.


And of course the old "discussion"..



> Teflon tape
> 
> The purpose of this white, nonsticking tape is to serve as a lubricant when threaded parts of a piping system are being assembled. The inherent slipperiness of the material makes assembly easier.
> 
> ...


http://www.plantengineering.com/sin...sealant/5103ee62235def2053cec5d46dd34156.html


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## Dman911 (Nov 24, 2016)

jeffkrol said:


> General opinion is that teflon tape "pieces" can make their way into the reg. innards..
> IF this is really an issue is a bit debatable..
> 
> Thinking back a bit don't believe any new regs had either..
> ...


Yes all true


This is the exact same as pipe dope.

Doesn't seal either although it will adhere to the surfaces this crates no benefit as its the taper of the pipe that makes the seal and is also used to lubricate the pipe threads only aid in reducing friction and damage to the threads. Also the tape should never be applied all the way to the end of the thread but rather a short distance to prevent excess being pushed into the fitting and is much easier to control with tape as opposed to pipe dope that can also if not applied correctly contaminate the air or fluid system. But I would not say one is better than the other for aquarium applications and rather a preference.

Pipe dope
Pipe dope has been used in industrial applications for decades. The material relies on a solvent carrier and hardens when the solvent evaporates. The resulting seal adheres to all plastic and metal pipes and effectively blocks leak paths.
Because it contains solvents, pipe dope has a tendency to shrink over time as the solvent dissipates. This condition creates the potential for the dope to pull away from the thread walls or crack, allowing leaks to develop. Pipe dope is usually applied to threaded components with a brush or spatula.
Advantages . Pipe dopes are inexpensive and relatively easy to use. Their chemical composition is compatible with all pipe materials, including plastic. Pipe dopes harden quickly and produce a moderate to strong seal.
Disadvantages . Solvent-based pipe dopes can lose their effectiveness as the result of heat aging. When the seal shrinks and cracks, leaks can develop. This possibility is especially true with systems that are subjected to significant vibration. Pipe dopes may lack sufficient resistance to solvents.
Recommended uses. Solvent-based pipe dopes provide an adequate seal in applications where high temperatures and pressures are not expected. Pipe dopes offer minimal resistance against vibration. They are acceptable when the installation of a piping system does not require adjustment of components more than a few minutes after assembly.

http://www.plantengineering.com/sin...sealant/5103ee62235def2053cec5d46dd34156.html

I have to say the over the counter pipe dope from most hardware stores or the stuff I have used does not dry quick nor seal although the info listed here disputes that but also states its not suitable for high pressure which would be why I find it doesn't seal because I have used it in high pressure applications. But I can say that if you are relying on pipe dope or tape to seal your fitting something is wrong and you should probably replace them. You can go buy a cheap pipe nipple covered in burrs and chips in the threads and chances are you will be needing to replace or repair them in the future. Getting a good tight fit on the thread is what's most important and a decent pipe or fitting will do just that.

Dan


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## jeffkrol (Jun 5, 2013)

> This is the exact same as pipe dope.
> 
> Doesn't seal either


We could argue that that statement is not "quite" true...  
Pressure effects and longetivity aside.. it does "seal" as a primary function, unlike teflon which it really is its secondary function.. (arguable)



> Pipe dope
> 
> Pipe dope has been used in industrial applications for decades. The material relies on a solvent carrier and hardens when the solvent evaporates. *The resulting seal adheres to all plastic and metal pipes and effectively blocks leak paths.*


you know it is complicated.. 


> Pipe Dope for steam
> 
> Hello
> I have used a quite a few pipe dope/ tape on steam and I would suggest you use the sealant that is best for the situation. In the event you have damaged threads and you have to fill the thread area use Expando Pipe sealant. The material is basically a form of concrete that by chemical intraction swells and turns as hard as concrete on curing. We used to buy it in fifty pound barrels; when we were doing ammonia installations. It will never leak and it is good for thousand of pounds of pressure. The arguement against it's use is getting the fitiing off again. It is very simple: heat the fitting to three hundred degrees and hit he fitting wiith an hammer -- this fractures the expando and you can turn the fitting out. I have also had good results with Gasolina harding shellac pipe dope. This is a hardening pipe dope and it is also great at sealing bad threads. Masters teflon and Masters Metallic are great for everyday use and work extremely well: they do not harden. In the event you have a problem and you wish to use a high tech porduct Teflon Pipe Sealant from Loctite has a pipe dope that if you use the curing sray for this product;you will get an amazing joint. Tape is good and I have had good results with it. I use the yellow tape for gas, as I find it works better than the thinner white product. The best tape I have ever used is the original product [ the first makers of tape ] it is made in Australia and it is the best tape I have ever used.The blue product you mention is an Loctite product and it is used extensively in the refrigeraton and airconditioning trade: I have had excellent results with it.I would suppose I am showing my age; but, I remember the days of red lead and cleaning the threads with white gasloine -- thanks heavens those days are gone! I hope this helps and good luck and all the best.
> Jack Ennis Martin


just found dope is much more forgiving for non-professionals..


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## Tvadna (Jan 17, 2013)

I am a plumber. I work with pipe dope and teflon tape every day. Regulators are higher pressure then water lines or residential gas lines but its the same idea. 

Teflon tape is not used on gas fittings. It can tear and block small orifices. There is a special kind of tape for gas (it is a light yellow) but nearly everyone just uses pipe dope.

Pipe dope has no cure time. It is ready to use immediately after applying. I personally don't care for the teflon pipe dope because it is thicker and more difficult to apply. My brother is also a plumber and it is all that he uses. The type doesn't really matter. You can go to a plumbing wholesaler and pay cash to pick up good stuff if you don't trust the orange aprons. (Box stores sell things that aren't legal or code to use all of the time). Contrary to what is stated above, pipe dope is used on compression fittings and sometimes on fittings with gaskets. It is not needed on fittings with gaskets but it helps prevent the metal from seizing up and allows the connection to be broken. I challenge anyone here to try to unscrew a fitting without pipe dope after 40 years.... You will fail.

The best possible seal would be to use the tape made for gas fittings (usually a light yellow in color). The tape has to go around the threads 3 times to be effective. The tape only works if you put it on the same direction the threads go. If you put it on backwards, it unravels as you tighten. After taping, pipe dope is applied. Nipples screwing into brass are typically not taped because brass is a softer metal and cracks easily if over tightened. It is much easier to over tighten when teflon tape is applied. Regulator bodies that are solid bodied aren't as likely to crack as something with a thinner knuckle you screw into, like the post body fittings.

With all that being said, I believe I just use pipe dope on my regulators. I wouldn't hesitate to tape and dope them if I thought they were leaking.
If you've damaged the male threads, you could just get a new nipple. If you damage the female threads, you may have to get a 1/4" tap.


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## Dman911 (Nov 24, 2016)

jeffkrol said:


> We could argue that that statement is not "quite" true...
> Pressure effects and longetivity aside.. it does "seal" as a primary function, unlike teflon which it really is its secondary function.. (arguable)
> 
> 
> ...


Yes I could have probably been more clear in saying I found that it does not seal in high pressure applications (which I consider true in this case because its high pressure that we have been talking about) but like I said we should not rely on these to seal a problem but rather aid in application (In this instance). I have also found in a last ditch attempt when the female threads are damaged on a housing such as a regulator a 2 part epoxy will seal and hold the pressure but you will never be able to take them apart again. I have done this 1000 times at least at a pressure of 240 psi, beyond that I have no idea.

I don't know how to quote some I'm just going in order here

It will only seal or block leaks as described when used in its proper application. So like I stated previously it won't seal either in this application nor in my past experiences with it in regards to pneumatic applications that I have used it on in the past but I have used it and works great for low pressure plumbing applications as I stated in an earlier post. 

I hope I'm not coming across as too argumentative because I'm not intending to be. I like to debate opinions and options as I almost always come away from the conversation learning something new. I previously worked in an Air Brake Shop for the railway for over 20 yrs. working on regulators solenoids, air dryers, brake valves etc. I can say this topic was debated for my entire 20 yrs of service there and some like me would swear by tape and some other would swear by dope. I think the most important is quality and material of the fittings.

Dan


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## Dman911 (Nov 24, 2016)

jeffkrol said:


> We could argue that that statement is not "quite" true...
> Pressure effects and longetivity aside.. it does "seal" as a primary function, unlike teflon which it really is its secondary function.. (arguable)
> 
> 
> ...





Tvadna said:


> I am a plumber. I work with pipe dope and teflon tape every day. Regulators are higher pressure then water lines or residential gas lines but its the same idea.
> 
> Teflon tape is not used on gas fittings. It can tear and block small orifices. There is a special kind of tape for gas (it is a light yellow) but nearly everyone just uses pipe dope.
> 
> ...


I agree with almost all of this with a few exceptions.. On stubborn pipes I always used both dope and tape also but that is always on black pipe I can tell you from working on 40+ old original equipment brass fitting will come apart no problem. 

I would have to disagree about using dope on compression fittings and gaskets. I can say that it is common practice for people to do so but its usually because ppl are taking short cuts compression fittings should at a minimum have the ferrule replaced if not be completely replaced when disconnecting and reconnecting (we all know this does not happen) which is why ppl put it on them. As far as doping a coupling again no dope or tape but again its common practice for a short cut. Anti-seize should be applied but it costs a little more and less ppl keep this on hand. 
e


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## jeffkrol (Jun 5, 2013)

I


> would have to disagree about using dope on compression fittings and gaskets



Agreed.. bad practice..
As to epoxy, just got done disassembling a solenoid metering valve assembly where someone used epoxy..Wasn't really hard to disassemble but made me wonder....


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## Stacy1 (Dec 15, 2016)

Just an update. Seems my regulator is broken. I went through the leak test and both sides held. I'm still waiting on my post body parts to arrive, but had a broken azoo co2 set up and took the post body from it and put it on the new regulator just to run until my parts come in. I set it up to run at 40psi because I'm using a typical glass diffuser. Sat in there and watch it for a few minutes and everything appeared to be working as it should. Thank God I went back about an hour later just to check on things. My working pressure was maxed out at 200psi and there was so much co2 going in the tank that it looked like the water was boiling. My fish were at the surface gasping for air. I immediately unplugged the solenoid, got some air stones in my tank to degas it and shut off the co2 tank. I took the diffuser out of the tank and charged the regulator again with the working pressure decreased all the way to zero. Soon as I turned the valve on the tank the working pressure immediately maxed out and it wont control. The high pressure guage doesnt even show any pressure before the low pressure side is maxed. The seller is giving me a refund but I really was hoping it worked. It was super nice looking and the price was right. Now I'm back to regulator shopping  . On the bright side though, my fish appear to be ok, and my needle valve and solenoid will be here today


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## Dman911 (Nov 24, 2016)

jeffkrol said:


> I
> 
> 
> Agreed.. bad practice..
> As to epoxy, just got done disassembling a solenoid metering valve assembly where someone used epoxy..Wasn't really hard to disassemble but made me wonder....



Yeah I have run into that several times where the surface prep was poor or not done and on the equipment I had to work with there was always oil contamination in the air supply, if it hadn't been cleaned off properly you could literally let it cure and unscrew it quite easily. 

Dan

Bump:


Stacy1 said:


> Just an update. Seems my regulator is broken. I went through the leak test and both sides held. I'm still waiting on my post body parts to arrive, but had a broken azoo co2 set up and took the post body from it and put it on the new regulator just to run until my parts come in. I set it up to run at 40psi because I'm using a typical glass diffuser. Sat in there and watch it for a few minutes and everything appeared to be working as it should. Thank God I went back about an hour later just to check on things. My working pressure was maxed out at 200psi and there was so much co2 going in the tank that it looked like the water was boiling. My fish were at the surface gasping for air. I immediately unplugged the solenoid, got some air stones in my tank to degas it and shut off the co2 tank. I took the diffuser out of the tank and charged the regulator again with the working pressure decreased all the way to zero. Soon as I turned the valve on the tank the working pressure immediately maxed out and it wont control. The high pressure guage doesnt even show any pressure before the low pressure side is maxed. The seller is giving me a refund but I really was hoping it worked. It was super nice looking and the price was right. Now I'm back to regulator shopping  . On the bright side though, my fish appear to be ok, and my needle valve and solenoid will be here today


Ouch!! At least you were around to catch it and glad it all worked out.

Dan


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