Plastic Vs Copper

[Aidan]

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.

Lightning strikes were the most usual reason for using fibre optics on Lan networks.

There's been a huge increase in thefts of copper, brass and bronze in electrical cables, fittings and sculptures. A few people have been electrocuted in the US whilst stealing live cables, whilst a few bronze war memorials and a couple of Henry Moore sculptures have gone walkies here.

 

[Penners]

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.

Despite their claims, I've never had the confidence in today's fluxes to solder without cleaning the tube ends and the fitting interiors. Can you really do it and achieve 100% satisfactory results?

What is the "something better" that you found for cleaning? Is scotchbrite suitable?

 

[NT]

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

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

Why do you think that?

If you look at the practices of the 1920s, a fair range of substances was used as fluxes. Unfortunately I dont have the book with the list in here.


NT

 

[Aidan]

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.

Despite their claims, I've never had the confidence in today's fluxes to solder without cleaning the tube ends and the fitting interiors. Can you really do it and achieve 100% satisfactory results?

What is the "something better" that you found for cleaning? Is scotchbrite suitable?

Silicon carbide abrasive cleaning strips.
http://www.bes.co.uk/nav_graf/frames_cat.htm?url=http://www.bes.co.uk/products/211.asp

They don't disintegrate and drop bits everywhere. A wire wool pad will get smaller as you use it.

The other thing about steel wool is that you get lots of little irritating wire fragments embedded in your fingers.

Copper fittings have some sort of varnish on them to protect them from tarnishing and acid fluxes will solder them without any/much cleaning. If they're old, tarnished and/or oily, I'd clean them. The active ingredient is usually zinc chloride which forms hydrochloric acid when heated (but I'm not sure about that). The acidic residues can cause big corrosion problems in heating systems if not flushed out and neutralized, but that's another story.

 

[Andrew Bodenham]

From all the debate it's clear that there are pros and cons with both copper and plastic systems. Both should give good service IF they are properly installed in line with manufacturers recommendations. The few problems I've heard about have been due to poor installation technique, e.g. not checking that all the 'O' rings / grip rings are present & in the right orientation. I heard of one good case where chromed copper pipe was used in a push-fit system for the visble run to an appliance. The grip ring couldn't cope with the hard chrome surface and over time the joint blew. Unfortunately the housholder was out for a few hours......

Personally I wouldn't trust plastic systems in my house, and I prefer the neater appearance of good copper pipework.

Penners - for cleaning prior to soldering I always use Scotchbrite type abrasive pads as they shred less, don't rust and are much nicer to handle. Dishwashing pads are no good - you need the genuine abrasive type.

Expansion noise needs to be designed out by considering how pipework will move under heat. When I put our CH in I lined all the joist notches etc. with felt. Result - silence.

 

[Penners]

the joint blew. Unfortunately the housholder was out for a few hours

But of course. This is a clear application of Sod's Law of the Immutable Perversity of Inanimate Objects.

I lined all the joist notches etc. with felt. Result - silence.

I find that silicone baking paper works well, too. Just tacked into the notch.