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The world of pipe fittings

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Re: The world of pipe fittings

#101

Post by cf100clunk »

imglorp wrote: post #36
mildchalupa wrote: post #27

The Teflon tape is only to be used as a friction modifier as NPT and other tapered threads seal on the threads. Reduced friction means that you can get enough load to deform the metal threads and create a seal. Be careful to not add tape to the first 2 threads as small pieces of Teflon tape can break off and get stuck into valves and things within appliances causing them to leak. There is nothing wrong with pipe dope…

> Relying on an o-ring Another category is Shark Bite, a simple push-on tech that is almost homeowner proof. All you need for many jobs is a cutter, some sandpaper, and the fitting: no pro tools, no torch. There are tight joist spaces the new copper crimper won't fit and overhead soldering is fraught, which you can sharkbite in 2 minutes. Back to O-rings, I do wonder about the lifetime of the seals in there though.

If Shark Bite products are not available there is also the Waterline Push-N-Connect line of similar products for homeowners:

https://waterlineproducts.com/products/push-fit-fittings-and...

There are other similar products from different companies.

Re: The world of pipe fittings

#102

Post by andylynch »

jcims wrote: post #78
hilbert42 wrote: post #42

Earlier quoted context omitted.

"You need about 1.5 wraps of PTFE tape to seal a fitting. Any more is wasteful and asking for leaks" I would have thought this obvious and it's essentially my experience (and I'm definitely not a plumber). However, I've found that more PTFE tape is needed on old or worn fittings or on ones that have damaged or badly cut threads—or when mating same sized pipes/fittings but each with different threads (yes, that's a de…

>Of course—not being plumber—it often happens that when I urgently need PTFE tape I cannot find it Ahh, young padawan, the way of the elder is to buy a roll every time you have a project to do until you have achieved saturation...where there is a lightly used roll of teflon tape in every drawer and on every surface of your workshop and garage.

This is the way. It’s also cheap enough that buying a dozen rolls upfront is less effort!

Re: The world of pipe fittings

#103

Post by sokoloff »

georgeoliver wrote: post #93
agsamek wrote: post #66

This article doesn't touch much about why plumbing is hard. I'm from Poland so I'm not only IT but also a plumber ;) Plumbing is hard because it is not forgiving. It's as binary as IT except you can learn the outcome with some delay, once you learnt about a damage caused by a leak. Either you do a pressure tests right or repair can be expensive. And bugfixing is always tricky. Water also goes down whether you like it…

I had a funny experience a week ago. One night working on a hobby web project it took me three or four hours to debug something, I finally got to bed around midnight thinking "boy, programming is hard". The next day at work we had to find a broken heat wire in a tiled bathroom floor, running 1000 volts through the wires to try to fuse the broken wire, then heating the floor up and searching with heat-sensitive paper…

Does a thermal imaging camera not work for the finding task? That seems like it would be faster, more certain, and less aggravation all around.

Re: The world of pipe fittings

#104

Post by VLM »

The story misses some points.

The first issue is pipes are used for a lot more than pressurized drinking water, and for compressed gases there's various standards so you don't accidentally connect your acetylene tank to your argon regulator and vice versa. Depending on local building codes, you have to work really hard in the USA to cross connect your natgas to your water supply, etc. For a home handyman this seems laughable but for giant construction projects at industrial sites you will inevitably see insane stuff sooner or later where roughed in water lines get accidentally connected to compressed air and stuff like that. I personally saw a PVC convenience pipe roughed in for ethernet cable get connected to sewer vent.

The second issue, related to the above, is NPT relies on thread deformation so the pros use pipe dope and the amateurs use teflon tape that contaminates everything, so you technically "can" use NPT for diesel or hydraulic but usually building codes and/or OSHA prevent such nonsense. Also thread deformation means every time you reuse a NPT its looser and leakier. Very slow leaking threads are not an issue for compressed air, so black iron pipe is common for industrial compressed air because who cares if 0.01% leaks out, but for flammable contamination sensitive stuff its a big issue. If 0.01% of your compressed air leaks out above a food prep assembly line nobody cares but if 0.01% of your hydraulic fluid leaks out into the food, then its a big food safety mess. The point is that most of this technology is being used outside its original use case, most NPT threads are not holding back compressed air, but crazy people are trying to use that tech to push natgas around or diesel or whatever and due to "tradition" and "codes" we are stuck with it. So the argument that NPT is shit so nobody should use it is pointless because its "really intended for" compressed air and is great for that, super cheap, easy to use, reliable enough, etc, so pointing out that its not optimal for car brakes is both true and also not useful "in practice".

Another comedy about threads: You can buy pipe dope to professionally seal NPT threads for air, natgas, car brakes, and water, but those pipe dopes are not the same, and you can cause quite a bit of trouble if you use air dope on natgas for example.

Re: The world of pipe fittings

#105

Post by PaulDavisThe1st »

jkqwzsoo wrote: post #9

In case anyone from the US reads this, BSPP and BSPT fittings are rare and incredibly frustrating here, as our NPT (National Pipe Taper) threads are different and the selection of BSP(P/T) fittings is extremely poor in comparison. Also, I work with NPT fittings quite a lot: > For what it’s worth, I tightly wrap the tape 10 times round the male thread and get an enraged mountain gorilla to tighten it up. This is a WTF…

Pipe dope FTW.

Re: The world of pipe fittings

#106

Post by sokoloff »

mindslight wrote: post #52
cmclaughlin wrote: post #44

Earlier quoted context omitted.

> I like PEX, but I know opinions vary What’s not to like about PEX?

Thinking about a system a half-step up from hose clamps holding 100psi of pressure, which if it pulls apart will rapidly release hundreds of gallons of water does not inspire confidence. And since the house is already plumbed with copper and I know how to sweat joints, I might as well continue that. I'm about to use PEX for the first time on my hydronic heating system, which is only ~20psi and limited volume (autofil…

Be sure to read up on oxygen barrier vs permeable Pex. (You probably already have, but if not, you almost certainly want barrier Pex in a closed-loop system.)

Re: The world of pipe fittings

#107

Post by mindslight »

D13Fd wrote: post #100
mindslight wrote: post #52

Earlier quoted context omitted.

Thinking about a system a half-step up from hose clamps holding 100psi of pressure, which if it pulls apart will rapidly release hundreds of gallons of water does not inspire confidence. And since the house is already plumbed with copper and I know how to sweat joints, I might as well continue that. I'm about to use PEX for the first time on my hydronic heating system, which is only ~20psi and limited volume (autofil…

I haven’t seen 100 psi in household applications

My city water pressure was around there, with few ill effects. I've since installed a pressure regular to drop it to around 60psi. But I liked it better before, especially on the silcocks.

It's not really the pressure that has me worried, but rather the potential flow rate. I've dealt with a flooded basement before, and I'd rather not do it again.

I don't see many people complaining that PEX fails by completely pulling apart, but it's hard for my intuition to accept that.

Re: The world of pipe fittings

#108

Post by kennend3 »

jkqwzsoo wrote: post #9

In case anyone from the US reads this, BSPP and BSPT fittings are rare and incredibly frustrating here, as our NPT (National Pipe Taper) threads are different and the selection of BSP(P/T) fittings is extremely poor in comparison. Also, I work with NPT fittings quite a lot: > For what it’s worth, I tightly wrap the tape 10 times round the male thread and get an enraged mountain gorilla to tighten it up. This is a WTF…

As someone who is NOT a pipe fitter but lived with one for many years.. It was odd reading this and I'm glad someone like you responded to correct things.

> For what it’s worth, I tightly wrap the tape 10 times round the male thread and get an enraged mountain gorilla to tighten it up.

Again, not a pipe fitter but this just screams "WRONG". If someone needs to use that much force to tighten it up, one can only assume that the pipe is now so full of tape it simply doesn't fit?

My roommate had a "unlimited BTU" gas fitter license (Canada Class "A") and this for a living and preferred "pipe dope"

"Pipe dope is generally stronger seal than Teflon tape, which is why plumbers and other professionals use it rather than tape for seals that are permanent."

Re: The world of pipe fittings

#109

Post by PaulHoule »

pasquinelli wrote: post #83
agsamek wrote: post #77

Earlier quoted context omitted.

> My complaint is that plumbers frequently do poor work for the money. Hehe - now you can feel like an IT customer. I think most people feel the same about IT but the domain is just more wide and prone to excuses.

people feel that way about stuff they have to pay for, generally.

No, I've never felt that way about a union electrician or generic handymen.

Re: The world of pipe fittings

#110

Post by Scoundreller »

jaggederest wrote: post #54
dotancohen wrote: post #37

Earlier quoted context omitted.

Those lead joints were leaching lead into the water. If it was a supply pipe, as opposed to a drain, then people were ingesting that lead. It needed to be replaced whether it was leaking or not.

The lead in those joints never touches liquid. It's a sealant on the back of the oakum, which is what does the actual water contacting. Also, nearly all water supplies (municipal, at least) are pH adjusted to be slightly basic, which causes lead to form lead carbonates and oxides, which is (basically) insoluble in cold water. Still good policy to replace lead supply lines, but not a crisis unless you allow your water…

More recently, beyond pH control, cities are doing orthophosphte corrosion control. Nearly universal in UK but hit and miss in other places.

https://www.haldimandcounty.ca/wp-content/uploads/2018/07/Or...

A big source of lead can be recently sweated copper lines (takes a while for the corrosion control to coat it), but lead solder isn’t supposed to be in potable use anymore. And old fixtures!

Even newer “lead-free” fixtures aren’t 0% lead.

https://www.epa.gov/sdwa/questions-and-answers-about-final-l...

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