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The world of pipe fittings

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Re: The world of pipe fittings

#121

Post by rsync »

kennend3 wrote: post #108
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…

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

I do this kind of thing a lot as we own and maintain our own water plant. My preferred sealant is the yellow PTFE tape that is used for natural gas.

It is quite a bit thicker than the white tape, it sticks to threads better and it is easier to work with, in terms of manual dexterity.

I never use the white tape for anything.

I don't like pipe dope at all and I only use it for large fittings that are going to be buried or inaccessible.

ALSO, helpful hint: If you are mixing plastic pipe (like schedule 40/80) and metal pipe, always have metal female couplings and plastic male couplings. A metal male going into a plastic female is one tighten away from cracking the plastic.

Re: The world of pipe fittings

#122

Post by VLM »

culopatin wrote: post #112
VLM wrote: post #86

Earlier quoted context omitted.

Tape causes massive contamination problems with fuel and hydraulic systems. Its not that the Teflon reacts with hyd oil, its that the inevitably little tiny bits of stuff physically jam/ruin seals and clog nozzles.

But only if you put the tape over the edge. I usually leave the first 2 threads uncovered, why would it fall into the stream if you don’t cover the tip of the thread with it?

The most installed/removed NPT thread will leak the most thus have the most tape added and the scraping of installation/removal will guarantee teflon contamination of the system eventually.

You are also correct in that something installed one time for the lifetime of the system, especially with some care and attention to cleanliness, is almost certainly OK.

Re: The world of pipe fittings

#123

Post by zbrozek »

amluto wrote: post #23
1970-01-01 wrote: post #15

They're paid so much because you need to pay twice for the bad ones. My house's previous plumber threaded a copper line directly into the stainless steel DHW tank. That wasn't a problem, until it was.

I’ve never encountered a DHW tank made of stainless steel with stainless steel fittings. The error that will destroy your pipes is to use anything copper in the condensate plumbing of a condensing boiler. Use PVC, CPVC or PEX (or stainless steel) with plastic fittings (PVC, CPVC, “engineered polymer”, or John Guest ProLock or similar). The high CO2 concentrations in the condensate will rapidly corrode copper.

https://www.chiltrix.com/heat-exchanger-tanks/DHW80.pdf

Re: The world of pipe fittings

#124

Post by dtjohnnymonkey »

bmalicoat wrote: post #92

I was hoping this was going to be written by Leslie Claret. https://www.lgclaret.com/ "Hey, let me walk you through our Donnelly nut spacing and crack system rim-riding grip configuration. Using a field of half-C sprats, and brass-fitted nickel slits, our bracketed caps and splay-flexed brace columns vent dampers to dampening hatch depths of one-half meter from the damper crown to the spurve plinths. How? Well, we bo…

This is what I came here looking for.

Re: The world of pipe fittings

#125

Post by hilbert42 »

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.

Ha! I'm no longer a Padawan so, like you, I'm well acquainted with the practice of spreading things around to the point of saturation.

It's not only PTFE tape that I spread around in copious quantities, other notables on the list are screwdrivers (of various sizes and types), superglue tubes (they go off with age anyway), propelling pencil leads, keys, USB and computer cables, USB pen drives, computer mice, adhesive tape, remote controls and any number of useful things.

The trouble is these supposedly inanimate objects come to life in the middle of the night and conspire not to be available when I most need them. Then the moment I've made do by jerry-built means they suddenly reappear! ;-)

Re: The world of pipe fittings

#126

Post by ok_computer »

Bsp, Npt, goop (yuck!), and teflon tape are all inferior to Swage. Cold weld and reuseable but it is a trade in itself to fit and bend to place.

https://en.m.wikipedia.org/wiki/Compression_fitting

Working in labs on fluid and vacuum lines (If only it wouldn’t cost as much as the house in fittings + tube to hardpipe stainless fittings on our water supply lines.

I stayed in a hostel hotel in Munich, DE with hard piped bathroom water lines. I was impressed and think they must have been in service for 30-50 years.

Re: The world of pipe fittings

#127

Post by beerandt »

skeptical_dog wrote: post #30
Tijdreiziger wrote: post #26

Earlier quoted context omitted.

> 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.

The english word, too, is derived from the Latin for lead: plumbum.

Except the meaning is to plumb, as in to level, as in to get water flowing downhill.

The lead refers to the (lead) plumb bob used to determine the direction of vertical and therefore what's level.

Re: The world of pipe fittings

#128

Post by baybal2 »

blincoln wrote: post #12

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…

No post body was provided.

Re: The world of pipe fittings

#129

Post by jaggederest »

Scoundreller wrote: post #110
jaggederest wrote: post #54

Earlier quoted context omitted.

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” f…

Yes I've found it's very frustrating looking for "genuinely zero lead" brass and bronze. Almost all scrap has lead in it to some degree, and even new metal often has a trace.

Re: The world of pipe fittings

#130

Post by scotty79 »

blincoln wrote: post #19
blincoln wrote: post #12

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…

Also, I should mention that I've used PTFE tape without any issues for air tool connections. It's just for plumbing - where even a slow, tiny leak can cause massive damage - where I think it's a terrible choice.

It's perfectly usable but you need to wrap a lot of it. If you wrap so long that you can barely make out a thread underneeth you can have a good seal lasting decades even if you don't screw the thread in completely.

On steel pipes and fittings obviously. Plastic ones might crack.

Also hemp fiber requires bit more practice and leverage but it's really good.

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