Solvent weld - how long should it last?

I was chuntering and mumbling a while back about someone installing a shower tray with all solvent weld where I could get at it, and a final compression joint under the tray where I could not.

I ended up chopping the tray up to get it all out.

I then found, working my way back up the pipework, that most of the joints were loose. I think they were all solvent weld, although my first thought was that the installer had used silicone sealant one one joint to allow it all to be taken apart again if required. There were signs of water getting out of the joint (dirty marks on the plastic pipe and the elbow all the way to the edge) so it looks as though at least one joint had been dodgy for some time (if not its entire life).

So, how long should solvent weld last? I assumed it was good for the life of the pipe but either this was a bad install or there is a limited life on solvent weld joints. I think the installation is betwee 10 and 20 years old.

Cheers

Dave R

P.S. I have reinstalled with solvent weld, but I have used a 'proper' shower trap which unscrews from inside the trap from the top, and allows you to remove it with the trap in situ and the shower tray also in situ.

Reply to
David WE Roberts
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A timely question i'd like to see an answer to - we're getting our en- suite done, and all *inaccessible* joints are being done with solvent, only the shower waste itself will be compression...

That said, it's only a utility room underneath - if need be, it can all be accessible by ripping the ceiling out :-} (part of it has to be replaced anyway due to leaks during the previous owners' time)

Reply to
Colin Wilson

Sounds like the joints weren't made very well in the first place. Paint on solvent, push in until it seats, and *twist* a bit. Perhaps "twist" didn't happen.

Reply to
dom

David WE Roberts wibbled on Saturday 24 October 2009 19:59

It should last as long as the pipe, unless it's been cocked up.

Solvent cement as you know works by taking a compatible plastic in solution (the cement) and having the solvent dissolve the surface of the plastic to be joined so that the cement's plastic can intermingle.

Once the solvent has evaporated, all you should be left with is a solid lump of plastic.

Obviously, things that can be done wrong include:

a) Failure to degrease and clean the parts if dirty;

b) Failure to apply enough cement;

c) Failure to apply cement to both parts - though you can IME get away with this is you put enough cement on and twist the parts after assembly;

d) Failure to sandpaper the pipe or fitting if they are coated with filth or paint, prior to a).

A joint that seemed good when made but wasn't might fail later due to thermal stresses.

Personally, I've not had a problem, yet - but I am carefull to do the job properly.

Yes - those things are the best solution.

Reply to
Tim W

snipped-for-privacy@gglz.com wibbled on Saturday 24 October 2009 20:25

I agree. Sometimes it's not always possible to do the twist (often on the last bit), but as I mentioned in my other post, if both parts are coated with cement, you should be OK, because at that point, all surfaces should be suitably disrupted.

Reply to
Tim W

e) Failure to use "solvent weld" type plastic pipe

Robert

Reply to
RobertL

Treat it as permanent. If done properly the the pipe will give long before the joint if you try and force it.

When done correctly, the pipes in effect are fused together - its the best solution for where joints will become inaccessible.

Reply to
John Rumm

Its hard since it is a different diameter (deliberately) - push fit pipe will not fit solvent fittings and vice versa. Universal (compression) fits both.

Reply to
John Rumm

RobertL wibbled on Saturday 24 October 2009 21:14

That is indeed a very good observation...

Push fit pipe being a mm or two smaller outside diameter that it's solvent weld counterpart (eg 41mm vs 43mm for the nominal 40mm size), means that even if the plastic is compatible, it may not glue successfully.

Possibly mixing uPVC pipe with ABS and not using a dual purpose cement (eg Floplast have one designed for both)?

Reply to
Tim W

It's amazing how many people think solvent weld is a glue and use it as such. Of course out of context it is as much use as water. :))

Reply to
ericp

In message , snipped-for-privacy@blueyonder.co.uk writes

You can irrigate deserts with it ?

Reply to
geoff

Or possibly no solvent applied at all. Solvent weld is a reasonably tight fit and a shower doesn't have a particulary high flow or any pressure(*). A little bit of capillary action leakage as described but not gushing out.

(*) Unlike from a bath or basin when the plug is pulled.

Reply to
Dave Liquorice

f) using just solvent, rather than plastic loaded solvent on pipes that are actually slightly different diameters..

Reply to
The Natural Philosopher

IME solvent weld is 100% as Tim says - if done correctly. I've found a few where it wasn't done correctly or wasn't done at all.

Reply to
The Medway Handyman

g) keeping it somewhere where it gets too cold during the Winter months (I've probably killed mine by forgetting about it in an unheated tool shed - not needed to try it all year to see if it's still good)

Reply to
Jules

I think you'll find all the solvent cements will work for uPVC, muPVC and ABS. The Osma and Marley ones certainly do. None of them will work on polypropylene (PP) pipe.

Also note that PP pipe isn't UV-stable and will disintegrate outdoors unless painted.

Reply to
Andy Wade

I replaced the kitchen here some 20 odd years after installing the first one and the original solvent weld Terrain was as solid as new. So I'd guess yours wasn't properly done.

Reply to
Dave Plowman (News)

There was definitely something apart from pipe in the joints - there was a clear residue which was hard.

Perhaps the incorrect cement was used? It looked as though there was some kind of clear glue which had not reacted with the pipe itself. I assume the result should be more like the old Airfix kits where the plastic was melted by the cement and then fused together.

As a mild aside, I bet you could form a reasonable bond just using the degreasing cleaner - it seemed to do a lot more than just remove grease, including removing the blue printing from the side of the pipe.

Evil stuff.

Reply to
David WE Roberts

David WE Roberts wibbled on Sunday 25 October 2009 10:31

Wrong cement or wrong pipe definately...

Indeed - it's exactly the same principle.

I would suggest checking the blue printing to see if it states the pipe is ABS (usual), PVC (can be, not so common on small wastes) or something that doesn't weld.

Reply to
Tim W

There are many -solvent- weld products on the market. It appears they dissolve just a little of the surface, evaporating before any proper joint can occur. The resulting joint is mechanically weak & circumferentially incomplete - with hard clear plastic parts. Puts you right off the technology.

The proper stuff creates a rigid assembly - much like an ultrasonic joint.

Long black PVC conduit subject to solar & winter cycling require a semi-flexible joint, otherwise the mechanical forces eventually cause separation. MK do 3, rigid, semi-flexible, flexible.

Reply to
js.b1

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