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The world of pipe fittings

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Re: The world of pipe fittings

#51
post #2

Having just completed a small project involving plumbing, this post on my blog comes from the heart.

There are plenty of technical comments here, but I have to say I got a great laugh from this post. I have dealt with many of the absurdities state side, so I can relate to your experience. By the time I got to the words Windows XP Screensaver, I was laughing so hard I couldn't read anymore. After finishing, I bookmarked you. Looking forward to more. Thanks.

Re: The world of pipe fittings

#52

I've helped out with some plumbing work in an older house, and it's pretty fascinating to see the progression of technologies. 100 years ago, most drain pipes in the US were massive cast-iron pieces with no threads at all. They were mated together, then the joint was filled with a compound called oakum. To really hold it together, the plumber would pour molten lead on top of the oakum. Just taking that stuff apart is…

> 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 (autofill valves are an anti-pattern). Maybe I'll fall in love, who knows.

Re: The world of pipe fittings

#53

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…

I've seen FNPT and MNPT but not FIP/MIP.

Re: The world of pipe fittings

#54

Earlier quoted context omitted.

For sure. Those oakum + lead joints were problem-free a century after they were installed. How many of us can expect that from the things we do at work? The only reason some of that pipe needed to be replaced was that it was fused (by rust) to mid-20th-century galvanized pipe that had rusted completely shut.

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 quality to fluctuate (ala Flint or a number of other US cities, sadly)

Re: The world of pipe fittings

#55
post #8

"When buying male fittings, it’s best to always get tapered ones so they fit in either." I tried that with a shop compressed air system and got lot of leaks, hissing, and the compressor turning on frequently. And I never did get the system not to hiss somewhere, so I can sympathize and ditto this rant. Even when using matching fittings, with gobs of tape and/or dope, and enough force to destroy multiple fittings, it…

Air hose standards are also annoying and differ from plumbing.

https://toolguyd.com/quick-guide-to-air-line-couplers-plugs/

Re: The world of pipe fittings

#56

Earlier quoted context omitted.

Normally the market is supposed to correct these things but sadly we've created a culture that looks down on physical labour. Now there is a small group that can charge whatever they want.

Is the market not supposed to reflect culture?

This is an outdated ideology. Now the market is meant to define correctness. Deviation from the perfect wisdom of the market is the only form of sin.

Re: The world of pipe fittings

#58
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…

I particularly hate the confusion that BSP and NPT cause. They're almost interchangeable (differing, iirc, probably on the angle of flank) and will get about three turns in and then leak or fail under pressure. In my world, this has led to graduate students spraying liquid nitrogen around. It's clearly the case that the two probably were supposed to be identical but diverted due to manufacturing differences in the distant past.

The standard advice I've been given when it comes to either vacuum or cryo fittings is "cut anything American off it as soon as it arrives and put DIN standard or KF kit on as soon as possible". Standards are a pain and that xkcd about there being too many of them is very, very true.

Re: The world of pipe fittings

#60

I've helped out with some plumbing work in an older house, and it's pretty fascinating to see the progression of technologies. 100 years ago, most drain pipes in the US were massive cast-iron pieces with no threads at all. They were mated together, then the joint was filled with a compound called oakum. To really hold it together, the plumber would pour molten lead on top of the oakum. Just taking that stuff apart is…

> To really hold it together, the plumber would pour molten lead on top of the oakum. This is pretty interesting, because plumbers are called 'lead-pourers' (loodgieters) in Dutch, and I had always wondered why.

And plumbers are called plumbers in English because they work in plumbings?

Same origin in English as well! (Plumbum = Lead)

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