Is pipe dope required on compression fittings?


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Old 10-11-07, 08:52 AM
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Is pipe dope required on compression fittings?

I'm replacing a toilet shutoff valve (rush-type job), and am using compression fittings. I don't have any pipe dope and won't be able to make a trip to the hardware store today.

So I guess my question is: Is pipe dope absolutely required? And more importantly, are there any alternatives that I can use? For example I'm pretty sure I have some teflon tape around here. Thought it was just for threads, but maybe it would be better than nothing in a pinch?

I've also read about using clear silicone caulk in the event that the fitting leaks. Does this go on the compression ring, or on the outside of the nut? Actually I don't even have any _clear_ silicone caulk; I'd be using the white stuff used for windows.

This is a cheap old house so I don't care what it looks like nor how long it holds up. My main water supply is currently shut off so I just need to get this replaced in any condition I can, with the materials at hand.

Thanks!
-core
 
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Old 10-11-07, 10:26 AM
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According to this article you can use tape.
http://www.doityourself.com/stry/installshutoffvalve

When I installed mine, I don't recall using anything but the valve.
 
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Old 10-11-07, 01:12 PM
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I don't use compression fittings much, but I don't tape or dope when I do.
 
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Old 10-11-07, 02:07 PM
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The only time I use tape is if I've taken apart the compression and need to put it back together. Don't think dope would do you much good in this situation anyway.
 
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Old 10-11-07, 02:46 PM
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Wink

Dont use anything on that compression fitting. Do make sure that the tube is all the way down into the fitting. Then tighten it
 
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Old 10-11-07, 06:55 PM
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don't use tape. if it needs tape to not leak then either the pipe or ferule are damaged. i do use dope on compression fittings but only on the threads as a lubricant. it does nothing for sealing up the joint, it just lets you crank it down easier without the metals seizing up. i think you'll be fine.





paul
 
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Old 10-13-07, 02:15 AM
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Thanks all.

Yesterday I just went ahead and put it on without anything else. After a bit of leaking and many 4-letter words I finally got it to seal properly.

Really the only "problem" I had was the fact that the ferrules on both lines refused to come off (even with solvents and such) so I had to reuse the old ones. Ditto with the old nuts then of course. If they had been damaged at all I would have been in serious trouble. Not looking forward to the day when I really do have to get one of them off -- sawing the pipe off really isn't a good option in this case.

Thanks again,
-core
 
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Old 10-13-07, 06:23 PM
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you should really replace the nuts and ferrules when you change an angle stop but if they don't leak now they probably won't. if you replace these valve again or any other ones in your home, you can buy a ferrule puller for about 30 bucks. don't buy the handle puller that has an adapter that allows it to pull ferrules, they don't work and are a waste of money.






paul
 
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Old 10-14-07, 09:50 AM
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Smile ferrules

core:...Really the only "problem" I had was the fact that the ferrules on both lines refused to come off...Ferrules don't come when they are installed correctly, they compress into the tube. There are ways that the pros may get them off but, if you are only doing a few you don't want to get into that. Glad things worked out, info only.
 
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Old 10-14-07, 07:37 PM
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I disagree with that article about putting tape on ferrules, although it is not the first article or TV show to suggest that. In my opinion, the tape can only get in the way of the ferrule sealing, and if on the threads, which are straight and not tapered pipe threads, it can interfere with proper tightening.

Not everyone agrees on this; I like a very light coat of teflon paste on the ferrule and the threads. This really is just a lubricant, and a little plumbers grease, or a drop of three in one oil, will suffice. Any of these techniques make unscrewing the nut years later, a little easier. I can confirm this from valves I have been back to some 10 years down the road.

I guess this is one of those areas where everyone has a certain way to do it, and if it works.... I never argue with success!
 
 

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