Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The world of pipe fittings

naich.net

Post reply on HN
Print view View original

181–190 of 270 posts

Re: The world of pipe fittings

#181

Post by jimnotgym »

blincoln wrote: post #70
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…

One of the things I like about it is that because it's flexible, if you route it carefully you can avoid using connectors in a lot of areas that rigid pipe would require a joint. The way I saw it used, the only joints were in areas like cleanout access and crawlspaces, so even if a joint went bad, it wouldn't require opening up a wall to fix. I'm not a pro, so maybe rigid pipe is supposed to only have joints in acces…

One thing about plastic pipe is that it is susceptible to rodent damage, unlike copper.

Seen it a few times.

Re: The world of pipe fittings

#182

Post by jakewins »

berjin wrote: post #171
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…

If you want a really good seal you wrap the tape 1-2 overlaps at the start of the thread and progressively make it thicker and thicker so you have more overlaps (10x) at the base. I guess it depends on the fittings but some run out of tapper and you can't tighten it anymore without the hexagonal nut hitting the adjacent fitting. This works well as you're building your own tapper which is sort of acting as an o-ring.…

Do you have a reference for this? Everything I've read is the purpose of the tape is to reduce friction (hence PTFE), not to actually seal. In other words, the seal comes from the fittings connecting tightly, made possible by 2-3 wraps of PTFE low friction tape.

Re: The world of pipe fittings

#183

Post by ssl232 »

thedanbob wrote: post #6

I had a major plumbing problem some time ago (leak in the house’s main line) and paid a plumber way too much to dig a hole and fix it. I of course wasn’t about to pay him to fill the hole back up, and while it was open I took a good look. That’s when I discovered PEX. PEX is wonderful: easy to work with, inexpensive, simple to fix if you screw something up. I wish all plumbing was PEX. I briefly installed an NPT flow…

I've not done any major replumbing yet but I've been watching Matt Risinger [1] on YouTube for a few months and have quickly become a PEX fanboi. He's a home builder based in Texas and uses PEX for basically every job. There are some videos on his channel comparing different types of PEX and PEX against other systems.

[1] https://www.youtube.com/@buildshow

Re: The world of pipe fittings

#184

Post by TeMPOraL »

mindslight wrote: post #148
hilbert42 wrote: post #135

Earlier quoted context omitted.

Right, see my reply to jcims but that's not all of matter. One could suppose I'm going senile and perhaps that's true but the fact is that I've been losing stuff like this since before I was a teenager. I've figured out the problem: my mind is thinking about all sorts of seemingly important stuff all the time but which in fact is mostly garbage, so my subconscious mind handles what my conscious mind consideres as pro…

My own working model is one of complexity building up over time. You can handle it fine as long as you don't have many fields of endeavor, you have plenty of time to periodically focus on them, keep the stuff organized, can fully finish a project and button it up, etc. But then things happen where you're forced to clear out your mental cache, or even screw up your organization/storage system for whatever, and it come…

Or you find yourself married and with children, and that final step of regaining some bandwidth becomes structurally impossible to achieve.

Re: The world of pipe fittings

#185

Post by hilbert42 »

mindslight wrote: post #148
hilbert42 wrote: post #135

Earlier quoted context omitted.

Right, see my reply to jcims but that's not all of matter. One could suppose I'm going senile and perhaps that's true but the fact is that I've been losing stuff like this since before I was a teenager. I've figured out the problem: my mind is thinking about all sorts of seemingly important stuff all the time but which in fact is mostly garbage, so my subconscious mind handles what my conscious mind consideres as pro…

My own working model is one of complexity building up over time. You can handle it fine as long as you don't have many fields of endeavor, you have plenty of time to periodically focus on them, keep the stuff organized, can fully finish a project and button it up, etc. But then things happen where you're forced to clear out your mental cache, or even screw up your organization/storage system for whatever, and it come…

Right, that makes sense. And my explanation is more complex than I could detail in my comment.

I know I have too many diverse interests—fields of endeavor to quote you—and the older I get the more of them I accumulate. On the one hand having many interests is very useful because it allows me to see and understand common ideas or threads across quite disparate and diverse subjects that otherwise would not have been obvious but the matter of administration becomes a significant problem. Often I've little time to deal with prosaic matters so the mundane is often left to itself (disorder accumulates).

That said, I'm instinctively an orderly and tidy person, as I like to say 'there's a place for everything and everything in its place'. I hate mess and disorder but that doesn't mean that I don't experience it—I do so often for reasons that you mention. However, when entropy/disorder around me reaches a certain 'sensibility' threshold I'm triggered to have an almighty cleanup much to the chagrin of others around who have a more relaxed view of disorder.

Nevertheless, I'm not obsessive about it, sometimes I amaze myself at the level of disorder I'll tolerate. (Reordering things is boring and distracts me from my interests despite the fact that I'm competent and thorough about it. Essentially, the more preoccupied I am with something the higher my toleration for mess and disorder becomes).

Re: The world of pipe fittings

#186

Post by CamperBob2 »

throwawayacc4 wrote: post #82

This article sucks. Lots of bad info from an inexperienced plumber. How the US military, nuclear power plants, and plumbers worth their weight in salt do fittings: 3-4 times around the (male) fitting with PTFE tape, then a light amount of pipe dope on top of the PTFE tape. Also, DO NOT buy the cheap PTFE tape as suggest. Buy the milspec tape. Your big box store will have both and you'll know where that money (a coupl…

3-4 times around the (male) fitting with PTFE tape, then a light amount of pipe dope on top of the PTFE tape.

That doesn't sound like a good idea at all. The whole idea behind PTFE (aka Teflon) is that it reduces friction because nothing, including pipe dope, sticks to it. What value does the pipe dope add to a properly-wrapped fitting?

Re: The world of pipe fittings

#187

Post by sacrosancty »

jimnotgym wrote: post #176
toast0 wrote: post #88

Earlier quoted context omitted.

They can't charge that much or people will do their own plumbing. It's fussy, but most routine things aren't too hard to do one step at a time. Sometimes you get a new faucet with an internal leak though, experience might have helped diagnose that without taking everything apart 20 times. Sometimes there's a big job like replacing a lateral, which is yeah, time to hire a pro.

In the UK gas work is regulated so only a registered plumber can do it.

In New Zealand, water work is regulated so only a licensed plumber can do it. The prime minister was once investigated by the Plumbers, Gasfitters and Drainlayers Board for installing her own toilet. Her punishment was having to apologize :P

Re: The world of pipe fittings

#188

Post by kortex »

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…

> You need about 1.5 wraps of PTFE tape to seal a fitting.

Not a pipe fitter, but I've done a lot of plumbing on a huge variety of systems (sinks, drains, air lines, HPLCs and other chemistry equipment, bioreactors, RO systems, potato cannons). I have found through experience that the thick PTFE tape (usually grey or yellow) is almost always superior to the thin tape. I use 2-3 wraps of that and that seems to be ideal.

Thick tape is also a lot easier to remove than the thin PTFE if you have to reinstall (you aren't supposed to re-use tape if you unscrew it).

Re: The world of pipe fittings

#189

Post by kortex »

mgarfias wrote: post #138
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…

A small quibble: the tape don’t seal. It’s a lubricant for the threads wedging together to seal. For a REALLY good primer on the subject, read Carrol Smith’s _Nuts, Bolts, Fasteners and Plumbing Handbook_ (aka Screw to Win).

> the tape don’t seal.

No, the tape absolutely contributes to the seal. Sure, the lubrication lets you thread more tightly without binding, but that's not to say the tape isn't contributing to the seal. If it didn't, you would still have a spiral leakage path. PTFE tape is soft enough that it deforms and prevents the spiral leakage path which can occur with any tapered threaded joint.

I've actually used PTFE tape in super high pressure situations (>1000 psi) with straight (un-tapered) joints (you aren't typically supposed to, but this was for an experiment), and it indeed sealed.

> The tape also works as a deformable filler and thread lubricant, helping to seal the joint without hardening or making it more difficult to tighten

https://en.wikipedia.org/wiki/Thread_seal_tape

Re: The world of pipe fittings

#190

Post by hilbert42 »

TeMPOraL wrote: post #184
mindslight wrote: post #148

Earlier quoted context omitted.

My own working model is one of complexity building up over time. You can handle it fine as long as you don't have many fields of endeavor, you have plenty of time to periodically focus on them, keep the stuff organized, can fully finish a project and button it up, etc. But then things happen where you're forced to clear out your mental cache, or even screw up your organization/storage system for whatever, and it come…

Or you find yourself married and with children, and that final step of regaining some bandwidth becomes structurally impossible to achieve.

It all adds up to what I call the 'overhead of living problem'.
Post reply on HN