Compression fittings, better to replace brass with copper olives?

[Sneezin]

Hi newbie around here and to the world of plumbing, but great forums and vibe here.

I just wanted to double check valve, I plan on re-doing some of my kitchen plumbing and replacing some compression fittings mainly isolation valves with the ones with little black tap handles since the old ones are very old and a slight leak (on olive end side). There connected to my hot and cold water tap via tap connectors to a Grohe tap.

The new isolation valves have brass olives, is it ok to replace them with copper olives?

Also to double check...

I read previous threads I should avoid ptfe tape, smear some jointing compound in front of the Olive and fitting (not on the actual olive or behind it) Is this still a good method on a new compression fitting?

I do have some fernox LS-X is that ok or should I get the Fernox pottable blue jointing compound tin?

Thanks

 

[Fred Blogs]

I am not a plumber but have done a fair bit of my own plumbing over the years. I suppose I will get shot down for this by the plumbers on this forum but in my opinion copper is better than brass. My reasoning is that copper is softer than brass and therefore will compress better/easier than brass so providing a better seal. Mind you if the pipe that the prersent isolators are fitted to have already been grooved by the previous fitting's olives then it will be very difficult, if not impossible, to make a leak free seal with whatever you use.

 

[Notch7]

I do have some fernox LS-X is that ok

thats what I use on olives with compression fittings -its goey like silicone sealant but Ive never had any leaks
Ive used it on radiator replacements where the tail has been badly mishapen by the olive due to overtightening in the past -and its held without leaks.

Im not sure how it should be used but I put a bit on the pipe, slide olive on then put a small smear over the olive and a tiny bit on the compression fitting where the angled shoulder tightens against the olive

nothing on the compression thread -no amount of PTFE would stop a leak

 

[Sneezin]

thanks, sounds like what I would be trying to do also will use the copper olives. I think I will use some steel wool and clean off my copper pipe work and check for any damage and yes I might have over-tightened the nut and olive so will check the pipe work quality but it should be fine no leaks for last few days I just nipped the spanner a bit more tighter.

I will just use the LS-X stuff if that is similar or better then the blue tin one, both say pottable so think they are similar although correct me if wrong.

 

[Rodders53]

I'm not a professional plumber but I never use anything to seal on compression fittings, other than the olive itself in the approx 40 years I've been doing work on my homes.

The sealants are a pain to clean off when I replace existing fittings done by the :self censored: builders of this house.

 

[Sneezin]

I'm not a professional plumber but I never use anything to seal on compression fittings, other than the olive itself in the approx 40 years I've been doing work on my homes.

The sealants are a pain to clean off when I replace existing fittings done by the :self censored: builders of this house.

I would ideally do the same but found even doing compression fittings hand tight followed by a few nips of the old wrench it can still have a weeping leak but these are much older fittings and older pipe work (probably 50+ years).

Sometimes I can nip it up a bit more and it stops the weeping leak, but figure id like a 2nd back up for peace of mind if anything.

Is your copper pipework and fittings 40 years+ or newer out of interest?

 

[Rodders53]

First home was ancient Victorian place I bought in 1980-1 so some imperial to metric. But a lot would have been brand new new metric.

I (with help/advice/teaching from my future father in law) install full gch, rewired and turned the cast iron bath 180 degrees to fit a shower. He never used any sealants - except on 'iron' items. Even that was mostly ptfe tape.

The nip up plus a 1/4 turn? is the normal on compression joints? Jointing pastes and similar are either a waste of time (the olive doing its job properly, or can mask a poorly made compression joint (in my opinion).

I know many of the pro plumber here disagree and will slap sealants anywhere and everywhere.

NB I also loathe the use of silicon sealant on basin and bath wastes. But that old fashioned me.

 

[Sneezin]

First home was ancient Victorian place I bought in 1980-1 so some imperial to metric. But a lot would have been brand new new metric.

I (with help/advice/teaching from my future father in law) install full gch, rewired and turned the cast iron bath 180 degrees to fit a shower. He never used any sealants - except on 'iron' items. Even that was mostly ptfe tape.

The nip up plus a 1/4 turn? is the normal on compression joints? Jointing pastes and similar are either a waste of time (the olive doing its job properly, or can mask a poorly made compression joint (in my opinion).

I know many of the pro plumber here disagree and will slap sealants anywhere and everywhere.

NB I also loathe the use of silicon sealant on basin and bath wastes. But that old fashioned me.

Yeah roughly a quarter turn, I tend to hand tight the isolation valve for example as hand tight as a I can and then roughly a quarter turn if not less obviously you reach that point where its pretty strong and don't want to over do it or damage something.

Yeah I can certainly understand not using any jointing compound of ptfe tape, I probably could just use the new copper olives and be fine but its just a nice thought not having to go under a cramp tiny cabinet again, also the family have too many pots/pans under there and there is a weird shelving system which is hard to disconnect and remove so ideally a job where you just want done the 1st time round.

 

[oldbutnotdead]

I prefer copper olives, they seem to make the 'hand tight plus 1/4 turn' much more reliable.

 

[DP]

I have never used any compounds on olives be it copper or brass. Brass olives may need a bit more force on the spanner to bite into the tube to form a seal whereas copper will be ok but will get mangled if too much force applied.

Boils my pi55 to see PTFE wrapped around the thread on the fitting. It is the olive that forms the seal, not the thread on the fitting. If the fitting has been taken apart, clean it and the olive area and PTFE may be wrapped around the olive to be sure to be sure.

Only time I will wrap PTFE on a new fitting is if it is in a place where it has to be water tight and Is going to be a hassle to take it apart again.

 

[SandyLyon]

I keep a bag of copper olives in my toolbox in case I have to break into or connect to plastic pipe, in which case I swop the brass olives for copper and use stainless steel inserts.

Otherwise, I just use the fittings “as they come” and never had any major problems.

 

[Madrab]

My rule of thumb is -

New fitting - no tape should be needed - can be copper or brass olives
Re-making old fitting after taken apart - Clean up fitting mating face with 120grit paper + 1 wrap of gas tape (I always have gas tape to hand) or 4 or 5 of normal tape around the olive only
Re-using an old fitting with new olive, same as above - clean up the mating faces with a piece of 120 grit paper and 1 wrap of tape as a belt 'n' braces

Copper olives are probably more DIY friendly though be careful as it is easier to overtighten/compress and then wreck the pipe and olive. If a compression fitting doesn't go watertight after hand tight and no more than 1 turn, then it isn't sitting right. Undo and put a wrap of tape around the olive and re-make. Happens more and more these day which is probably a sign of much looser manufacturing tolerances & quality of the cheaper fittings.

 

[ETAF]

fittings mainly isolation valves with the ones with little black tap handles

i assume you mean the small plastic handles - this sort of thing

Isolating Valve with Handle 15mm - Screwfix

Order online at Screwfix.com. Brass, steel and plastic construction. ¼-turn operation. Compression connection. Suitable for water. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

i had these new in a central heating bypass fill valve, and they broke , that was around 2014 , and had only been in over a year - same for a new bungalow - had to use pliers to turn

I replaced with full bore and handles on - or where i had plastic , full circle taps

 

[roguetrader]

A little bit of paste on compression fittings gives you a little bit of back up.
Nut and olive on, small smear of paste round, crank them up, move on.