Pipe Dope, Plumbers Putty, or Teflon Tape?

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Tuttles Revenge

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I sent an email to brasscraft for an explanation as to why they don't like tape but will accept dope or oil.

Their response:
Per our engineering team,

Tape can interfere with getting a seal if that gets between the sealing surfaces. We recommend the use of oil or thread sealant. Not tape.


So long as you keep the tape out of the sealing surface then it acts just like dope or oil on the threads.
 

wwhitney

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Agreed, but to me it seems simpler and safer to use a lubricant/non-sealant, rather than a lubricant/sealant. As the sealant aspect on the threads is strictly a negative, and you have to be careful to keep it off the ferrule.

It would be interesting when installing multiple valves to do some with dry threads, and some with just a drop of oil, and compare the torque required in each case for Brasscraft's spec of "3/4 turn pass hand tight," as well as observing whether that "hand tight" is the same engagement with and without oil.

If the torque required dry isn't excessive, that's certainly the simplest option, to use nothing on the threads.

Cheers, Wayne
 

Reach4

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compression ring
That is what they are calling the ferrule. AKA "compression sleeve".

I wonder what causes their objection to the pipe dope on the ferrule/olive.
 
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Jeff H Young

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Don't use tape on a compression joint or on a flare joint like gas connection etc. On compression I ALWAYS put a small amount of pipe dope on the the angles stop threads not even all the way around it necessarily but just to lube the threads a very small amount when it is chrome plated the threads sort of gall ,squeak , and sometimes leak if they are brass not so much problem. oil might work but I don't like oil because it unless you have the right kind it might not lube properly if anyone has ever tried threading pipe with motor oil in a pinch it doesn't work good, threads come out all tore up Ive used pipe dope and its better than motor oil its a mess but if using hand dyes with no cutting oil you gotta gettr done . When I started plumbing on new homes and we had many drips under angle stops they were tight as heck but no dope on them. I've revere heard of oil on the threads but if any one has done hundreds or thousands with good luck please comment if you are a believer in oil.,
 

JeffNC

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I personally have never heard any technical explanation for why you would use both dope and tape. It doesn't make any sense to me. They get in each other's way. If dope is better, use that, and if tape is better, use that. That's my thinking. Both claim to lubricate and seal. Personally I trust dope when it comes to sealing a threaded joint, especially something like a shower arm that can't be tightened to exactly where you want it.
 

JeffNC

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I appreciate your patience. Can you help this amateur and define "installed right"? Plumb and level and straight I know. Round and smooth I understand :) More than hand tight, or snugged up, or... ?

The parts are soft plastic. If they are aligned correctly and there is no grit or anything else to get in the way of the seal, it will compress correctly and be leakproof for non-pressurized drains. Hand tight is tight enough (but we don't all have the same hand strength do we?) It will compress the plastic and form a good seal. Anything else in there just gunks everything up. If it's leaking, something is wrong - don't add pipe dope to fix it.
 

JeffNC

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Interesting. I was always taught to dope all unions. So all traps, tailpiece washers, and all that...all doped. I've had sink traps assembled by others that were tight, but no dope, and leaking. I've disassembled and doped and retested and all OK.

It's a band-aid to fix a problem that should be fixed a different way. It's not simply a matter of being tight. It could be misaligned, it could be cross threaded, it could have some grit in there, it could be a defective part. In fact I've actually seen where someone has used pipe sealant, then when replacing something like the faucet (including the sink drain) and putting it back together it started leaking, because a hardened nugget of the old pipe sealant blocked the seal.
 

DIYorBust

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I personally have never heard any technical explanation for why you would use both dope and tape. It doesn't make any sense to me. They get in each other's way. If dope is better, use that, and if tape is better, use that. That's my thinking. Both claim to lubricate and seal. Personally I trust dope when it comes to sealing a threaded joint, especially something like a shower arm that can't be tightened to exactly where you want it.
In many situations, I think that's true, but as a DIYer who works on >80 year old joints, there are time when I like to use both. For example, I generally feel that tape makes the joint easier to take apart a few years later than most dopes, but the dope generally does a better job if there surfaces are a little less than perfect. If you can replace the parts, ok sure, but if it's a threaded brass tee that's going to mean a lot of work in a spooky crawlspace if it doesn't seal, I'll add a little dope to that tape.

I'd have to imagine if you were doing dozens of joints, and wanted to minimize the chance of a leak due to a bad fitting, you might find the same.
 

Tuttles Revenge

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I personally have never heard any technical explanation for why you would use both dope and tape. It doesn't make any sense to me. They get in each other's way. If dope is better, use that, and if tape is better, use that. That's my thinking. Both claim to lubricate and seal. Personally I trust dope when it comes to sealing a threaded joint, especially something like a shower arm that can't be tightened to exactly where you want it.
I was taught to use both.. But later asked Why?.. no answer other than That is the Way We Do Things... I asked Hercules and they said that they Only suggest using Dope over Tape on 2" and larger threads.
 

Terry

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Most of what I do is base on decades of experience of doing it in the field. I have done everything anybody else has ever mentioned. I can make any of them work most of the time. There are a couple of "go to's" that I often resort to.

For some history. When I was a child, my mother told me how she had helped her day at water lines and electrical wires to their home in Chimacum Washington. A small farm, with barn and chicken coop. She used to rub a bar of soap on the pipe threads to lubricate them so that they will thread in and seal.

You can also thread metal fittings with three wraps of tape, pipe dope, three wraps and some dope brushed over.

For anglestops, I was an apprentice, required to disassemble the nuts off of them out of the box and brush them up with dope. One day I read the instructions on the box, Use light lubricate on threads. So then I started spraying them with WD40.
I have installed them right out of the box and they work, sprayed them with oil and it works, touched just a little pipe dope at the end of the threads of the stop where the sleeve will rest. Brasscraft doesn't like dope touching the sleeve. I use just a little though.
 
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Reach4

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I have used some pipe dope on the threads first to help hold the tape in place. I have not done many joints. I think using both is more important on plastic threads, where you don't want to over-torque.

I have used pipe dope on brass compression nuts for lubrication, as an alternative to silicone grease. I have also used dope on brass compression ferrules. This was after I had a leak when I did not use the dope, but I also used more torque on the re-do. The extra torque would have probably been sufficient.
 

Terry

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COPPER COMPRESSION INLET
1. Place compression nut and sleeve onto the copper tube.
2. A drop of general purpose oil will make tightening easier.
3. If using a drop of oil or thread sealant be sure the threads are clean of any debris and that sealant is also free of any metal debris. DO NOT USE a putty, gasket material or thread seal tape.
4. If using a thread sealant, apply a thin even coat to the male compression threads only taking care not to get thread sealant on the compression ring or sealing surface. IMPORTANT: Excessive thread sealant may cause joint to fail.
5. Hand tighten the compression nut onto the stop as far as it will allow.
6. Using hand tools, tighten 3/4 turn from the hand tight position. Note: Make sure that the stop remains seated and square to the copper tube. If the stop is not square to the copper tube, this could affect the ability to get a good connection. CAUTION: DO NOT OVERTIGHTEN as this could lead to future failure.
7. For riser tube installation, see that section.

CAUTION: STOP MUST BE USED IN THE FULLY OPENED OR FULLY CLOSED POSITION.

brasscraft-compression-nut.jpg


COPPER COMPRESSION OUTLET
1. Cut the riser tube to length so it bottoms out in the stop.
2. Place compression nut and sleeve onto the copper tube.
3. A drop of general purpose oil will make tightening easier.
4. If using a drop of oil or thread sealant be sure the threads are clean of any debris and that sealant is also free of any metal debris. DO NOT USE a putty, gasket material or thread seal tape.

brasscraft-compression-outlet.jpg


FLEXIBLE NUT X NUT CONNECTOR
Be sure to shut off water before starting.
CAUTION: BE SURE TO IDENTIFY THE CORRECT WATER SUPPLY CONNECTION BEFORE BEGINNING INSTALLATION PROCEDURE. APPLICATION OF THIS CONNECTOR WITH THE INCORRECT WATER SUPPLY CONNECTION MAY CAUSE LEAKS.
1. Shut off water supply at stop.
2. Remove old supply tubes.
3. Thread wing nut of connector onto faucet shank or toilet ballcock and hand tighten only. For connectors with metal nuts, hand tighten, then wrench tighten 1/4 turn more. CAUTION: DO NOT OVERTIGHTEN as this could lead to future failure.
Tools Needed for Installation: • Wrench • Protective cloth
NOTE: Connector includes washers, DO NOT USE THREAD SEALANT.

brasscraft-flexible.jpg


PEX COMPRESSION OUTLET
Be sure to shut off water before starting. NOTE: On 3/8 in. OD and smaller, use plastic compression sleeve. On tubing larger than 3/8 in. OD, use brass compression sleeve w/stainless steel tube insert.
1. Cut the riser tube to length so it bottoms out in the stop.
2. Place compression nut and sleeve onto the PEX tube.
3. If larger than 3/8 in. OD, insert stainless steel tube insert.
4. A drop of general purpose oil will make tightening easier.
5. If using a drop of oil or thread sealant be sure the threads are clean of any debris and that sealant is also free of any metal debris. DO NOT USE a putty, gasket material or thread seal tape.
6. If using a thread sealant, apply a thin even coat to the male compression threads only taking care not to get thread sealant on the compression ring or sealing surface. IMPORTANT: Excessive thread sealant may cause joint to fail.
7. Hand tighten the compression nut onto the stop as far as it will allow.
8. Using hand tools, tighten 1-1/2 to 2 turns from the hand tight position. Note: Make sure that the riser remains seated and square to the stop. If the riser is not square to the stop, this could affect the ability to get a good connection.
CAUTION: DO NOT OVERTIGHTEN as this could lead to future failure
9. For inlet tube installation, see that section

brasscraft-pex-outlet.jpg
 

Terry

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SLIP-JOINT OUTLET
Be sure to shut off water before starting. NOTE: Do not use pipe compound on slip-joint threads.
1. Be sure tube is not flattened out-of-round and all burrs are removed. If tube is oval or out-of-round, do not rely on the nut to correct. Bring into shape before tightening nut. Replace tube if it is grooved, pocked or scarred as abrasions prevent a good seal.
2. Slide slip-joint nut, friction ring and cone washer onto tube.
3. Be sure tube is lined up with valve so it enters straight and “bottoms” true. If cocked or tilted, nut will not seat properly and could eventually develop a leak.
4. Tighten nut, wrench tighten. DO NOT OVERTIGHTEN. Use tape to protect the finish.
5. Turn on main water supply. Turn on valve counterclockwise. If slip-joint nut leaks, turn off water supply. Back off (loosen) nut completely, realign and retighten. CAUTION: DO NOT OVERTIGHTEN as this could lead to future failure.
Tools Needed for Installation: • Wrench • Protective tape • Sandpaper or file (if necessary

brasscraft-slip-joint.jpg


COLD EXPANSION PEX ON INLET
Be sure to shut off water before starting. For use ASTM F876/F877/F1960 PEX only. CAUTION: ASSEMBLE STOP ACCORDING TO PEX COLD EXPANSION TOOL MANUFACTURER’S INSTRUCTIONS.
1. Cut PEX tube so that the end is square and round.
2. Slide the PEX reinforcement ring over the PEX tube.
3. Follow the PEX cold expansion tool manufacturer’s instructions for installation of the stop barb inlet.
4. For riser tube installation, see that section.
Tools Needed for Installation: • Tube Cutter • Expansion Tool

brasscraft-expansion.jpg
 

Jeff H Young

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Chrome plating on compression stops often kind of galls squeaks when tightened. Yea instructions say oil , I think not nearly as good as pipe dope or even anti seize but I'm splitting hairs a small amount of lubricant on the threads doesn't really have to be all the way around
 

Charlotte22

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Any general rules for using which, when, why? Or the opposite, why /not/ to use which, when? :)

Thanks...
Hai, For direct-pressure, water and gas supply lines, Teflon tape or pipe dope is applied to the threads. For the purpose of preventing water incursion, plumbers' putty is used between mating surfaces.
 

Buzzards27

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I see more than one person saying they use pipe dope AND Teflon tape. My last home build the plumber sub I used for the gas used both on the joints. During the inspection the local building official rimmed out the plumber saying never use both on gas. Fortunately, we passed inspection and the pressure test and we were good.

What's the best practice? What's code? Is gas the exception?
 
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