Problems sealing compression fittings.

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cotton_250

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I purchased several 15mm Compression fittings from Toolstation (made for trade brand)

I’ve never had a problem with sealing compression fittings, but these just won’t seal!

I cleaned the pipe, and did them about a quarter turn tight.

They are now overtightened, as I tried all I could to get them to seal, but they are weeping very slightly.

What have I done wrong?
 
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I buy made for trade, I’ve not had any leaks although I always put a thin coat of sealant on the olive.

I’ve no idea if this the correct stuff to use, but it’s what I use

I use to use Fernox L-SX but it’s like very sticky silicone

www.screwfix.com

Flomasta Gas & Water Jointing Compound 250g - Screwfix

Order online at Screwfix.com. Soft-setting thread sealant for gas and potable water applications. Prevents leaks from threaded joints. Suitable for use by Gas Safe registered installers. Working temperature: -45° to 260°C. Maximum working pressure liquids: 10,000psi, gases: 2000psi. FREE next...
www.screwfix.com www.screwfix.com
 
If a new compression fitting leaks then never try to tighten it past normal and it's will only damage the pipe. If it won't seal then time for a new copper olive or worst case a wrap or 2 of tape around the olive.

Sometimes happens if the pipe is slightly undersized (loose olive) or slightly out of round, not all copper pipe is the same these days unfortunately
 
Madrab said:
If a new compression fitting leaks then never try to tighten it past normal and it's will only damage the pipe. If it won't seal then time for a new copper olive or worst case a wrap or 2 of tape around the olive.

Sometimes happens if the pipe is slightly undersized (loose olive) or slightly out of round, not all copper pipe is the same these days unfortunately
Click to expand...
I tightened them more out of desperation, it has sealed all but 1 now

I also purchased some B&Q fittings, and these sealed without any issue

It doesn’t seem to have damaged the pipe too much but it has squashed the olives, (they look like copper olives). will this cause any problems later on?
 
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Most of time, I find that ensuring the pipe is squeaky clean and the olive is copper, then applying a smear of silicone grease around the olive gives me a seal. I only use LS-X if there's a weep I can't stop.
 
justigator said:
Most of time, I find that ensuring the pipe is squeaky clean and the olive is copper, then applying a smear of silicone grease around the olive gives me a seal. I only use LS-X if there's a weep I can't stop.
Click to expand...
The pipe was spotless clean, I cleaned it up with wire wool before I cut it.

What are the best olives to use on copper pipe?
 
I always use copper olives, brass go in the scrap bin, as said above, if you get a weep, undo nut and wrap a couple of turns of PTFE around olive, never fails.
 
I got some brass olives from B&Q, and cut off the copper ones. the new ones sealed perfect with a ¼ turn

I'll never use copper olives again!
 
cotton_250 said:
I got some brass olives from B&Q, and cut off the copper ones. the new ones sealed perfect with a ¼ turn

I'll never use copper olives again!
Click to expand...
Ahhh why are you confusing things I thought it was copper all the way - now its brass - ahh
 
Nope ... copper every time. The trick is not to tighten them too much, too tight and they can leak. Brass can be much more problematic when it comes to being water/gas tight but with brass then you can get away with tightening them more without deforming.

The trick with brass is getting then to the squeak point.
 
Madrab said:
Nope ... copper every time. The trick is not to tighten them too much, too tight and they can leak. Brass can be much more problematic when it comes to being water/gas tight but with brass then you can get away with tightening them more without deforming.

The trick with brass is getting then to the squeak point.
Click to expand...
thats interesting, I think I shall buy a pack of 15 & 22 copper olives and throw out the brass ones that come with compression fittings from now on.
 
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