Plastic Vs Copper

[Gervase]

The thin layer in the heating pipes is a barrier material to stop oxygen permeating through the pipe and sludging up your heating system - it's why plastic pipe for heating costs a little bit more.
As for the stress of beinding; I can't imagine bending plasic to the point where it's stressed - that's what the various elbows are for. And the manufacturers recommend a 'loose' fit, with enough sag to allow for expansion and contraction over time. I suppose time will tell. The oldest plastic pipework I've encountered has been about 12 years, and it was still as sound as the day it was connected.
If plastic piping is a useless as has been suggested, why on earth has it been OK'd under Parts G & J and Reg 7 of Building Regs, and how come insurers are prepared to accept it in buildings?

 

[middi]

Thanks for clarification on the pipe construction Gervase, that makes good sense.

As to their longevity, apparently these pipes have been used for over 20 years already with a very good success rate, I am told, and following improvement and advanced technologigal manufacture they should be very long lasting.

Who Knows ?. One truth may be that old habits die hard and earning potential for fitters is speeded up.

 

[Me!]

I remember using plastic pipe and fittings about 25 years ago in Spain. From what I remember, plastic was virtually ubiquitous there even then so had presumably been in use for many years before that. Does anybody have, or know of, a villa in Spain with leaking pipework? I still only use copper in England though!

 

[Geoff Flegg]

By the way, I disagree that bending springs are a pain in the &*^%. They're actually a pain in the knee!

Quite right, but the worst bit is when they jam inside the pipe!

I wonder if people made the same comments about copper when that was introduced that we make about plastic ?

"That thin copper stuff will never last, not like good old lead / threaded iron......."

 

[Nemesis]

In my house a great deal of piping is exposed for a variety of reasons. I think copper less obtrusive than plastic would be. Also I am sure that placcy would have been gnawed by now by small furry creatures.

 

[middi]

I agree that any exposed pipework should be in copper.

 

[Penners]

Stress?
You have used a word that plastic piping is unable to deal with at all.

I used the word in a general sense to indicate any reshaping of the pipework. For example, if you curve plastic pipe around - say - a beam, then it is stressed to a certain extent (ie: it is not in the shape it would naturally adopt if unaffected by outside influences).

Plastic pipe will cope perfectly well with such stressing, provided you don't get silly about the radius of curvature you try to impose upon it, wouldn't you agree?

 

[Lime]

Stress?
You have used a word that plastic piping is unable to deal with at all.

I used the word in a general sense to indicate any reshaping of the pipework. For example, if you curve plastic pipe around - say - a beam, then it is stressed to a certain extent (ie: it is not in the shape it would naturally adopt if unaffected by outside influences).

Plastic pipe will cope perfectly well with such stressing, provided you don't get silly about the radius of curvature you try to impose upon it, wouldn't you agree?

Yes!
I was only being pedantic.
Plastic isn't stressed when it is bent normally as any potential stress is relieved by the molecules adopting a different shape and position.
As you say problems do arise when it is bent excessively (causing permanent stress damage) and when the stress is caused at a particular point of contact like a nail head, brick edge or pointed stone.
Most plastic is temperature sensitive too. Too hot and the plastic can stretch and weaken, too cold and the molecular structure cannot move sufficiently when bent and is damaged.
Age also plays a role as the plasticisers evaporate or leach out leaving the plastic more brittle.

 

[Penners]

Age also plays a role as the plasticisers evaporate or leach out leaving the plastic more brittle.

That explains what I see whenever I look in the mirror.

A clear case of evaporated plasticisers if ever there was one.

 

[alice]

Ah, Penners, but do you shatter when stressed?

alice

 

[Penners]

Actually I'm pretty shattered* most of the time.

It's something to do with being indispensible, irreplaceable, omniscient, multi-skilled, multi-talented (and an inveterate liar).


*British colloquialism meaning extremely tired; exhausted.

 

[Aidan]

To answer the original question, people will pay more for the plastic bits so the retailers charge more. I don't think it has much to do with the cost of manufacturing. People will pay more 'cos the placcy saves on labour costs. Copper bits to the relevant BS will fit anyone's BS copper tube. The plastic bits will usually work on any tube, but the manufacturers won't guarantee a pick & mix system. They'll try very hard to dodge any liability for their own stuff.

The main problem with copper is the price, which is going up exponentially. It gets nicked on site and gets nicked from vacant buildings. Most new-build uses plastic. I suspect copper plumbing will become unobtainable in our lifetimes.

The "rubber" 'O' rings are plastic (neoprene?), they don't perish as rapidly as rubber, probably good for 25 or 30+ years. I'm not aware that they are liable to perish.

Rodents will gnaw plastic, they'll also gnaw PVC cable insulation. Chavs will steal copper.

Speedfit is PEX (cross-linked polyethylene). HEP2O is polybutylene. Polybutylene was withdrawn from sale in the US due to adverse publicity after a big law suit. It was one manufacturer's fittings that were failing, apparently, not the tube itself.

You shouldn't use wire-wool to clean copper prior to soldering. It can leave stel strands in the joints and is coated with an oil (lanolin?) to stop it rusting.

The click-click noises emitted by some heating systems are due to the linear expansion of the copper tube, usually when used with on/off thermostat controls. It has nothing to do with how the pipes are soldered.

I agree that any exposed pipework should be in copper.

Yes, mainly 'cos plastic has a huge cofficient of linear expansion, so it goes noticeably 'saggy' when used with heating or a hot water supply system.

Plastic has it's uses, it has proved to be reliable, so far. It's mostly associated with push-fit systems, but the crimp fittings (Rehau & Uponor) are extraordinarily strong. You won't see them in the DIY sheds because they need an eye-wateringly expensive tool to fit them.

 

[Penners]

You shouldn't use wire-wool to clean copper prior to soldering. It can leave stel strands in the joints and is coated with an oil (lanolin?) to stop it rusting.

So what happens if you do use wire wool, Aidan? (As I always do! ).

My soldered joints seem to be OK.

 

[Flyfisher]

The main problem with copper is the price, which is going up exponentially. It gets nicked on site and gets nicked from vacant buildings. . . . . Chavs will steal copper.

I once worked on some comms projects in India and they were very keen on using optical cables because they have lots of trouble with people stealing 'normal' wiring. OK, this wasn't the primary reason, but I never encountered this as an 'advantage' for optical cables anywhere else.

 

[Penners]

I wonder whether that would be the case nowadays, since India's 'technological revolution'. I suspect the optical cable might be more attractive than the copper.

 

[NT]

You shouldn't use wire-wool to clean copper prior to soldering. It can leave stel strands in the joints and is coated with an oil (lanolin?) to stop it rusting.

So what happens if you do use wire wool, Aidan? (As I always do! ).

My soldered joints seem to be OK.

You get a nice bright finish that solders properly.

It takes some carelessness to leave strands left behind.

IIRC lanolin has been used as flux before, way back when.


NT

 

[chuckey]

Use a stainless steel pot scourer, they are wonderful because they don't rust.
Frank

 

[bower1]

Where I've used plastic, I've gone for the Hep2o fittings as they undo and the O'ring can be replaced. Not sure that it would ever work, but it gives me (false?) peace of mind. Never had a problem though, but time will tell...

 

[Flyfisher]

I wonder whether that would be the case nowadays, since India's 'technological revolution'. I suspect the optical cable might be more attractive than the copper.

Yes, that was my point - they did prefer optical cable for many reasons, including the fact that people steal copper wiring when strung along roads and railway lines.

 

[Aidan]

So what happens if you do use wire wool, Aidan? (As I always do! ).

My soldered joints seem to be OK.

You get a higher proportion of joint failures, steel residues in the pipes and within the joints. If you're trying to clean the tube ends of surface oxidation and gease, a friable pad of steel fibres coated with an anonymous oil is probably not the best thing to use. There're better cleaning materials available.

I used to use it too until I found something better. You don't need to clean new fittings & tube ends with most (active) fluxes.

IIRC lanolin has been used as flux before, way back when.
NT

I think you may mean tallow. http://en.wikipedia.org/wiki/Tallow

Tallow was used as a flux to solder lead, I doubt that it would be much use with copper.