Bathroomsink waste drain has a thick gel reducing flow

[Mike13]

As title I have a bathroom sink that has lost its flow in the waste drain. I have removed a ball of hair ang gel from the trap underneath the sink, but I can see and feel that the gel has got all the way along. It has improved with removing the hair ball, but running both hot and cold on max makes the sink start to fill up more than it used too.
I have previously tried caustic soda and that did not make much difference. I seemed to have more luck with HCl solutionlast time this happened. I think it is hair products blocking the drain but cannot be sure what it is.
Any ideas how best to get the waste pipe clear, it is about 5m long with 4 off 90 degree bends in total, so rodding is not feasible. The sink is on an internal wall and passes round under the bath to get to the outside, so not the best of access there either.

 

[jj4091]

Are the bends glued elbows or 90degree curved bends? You can buy cheap endoscopes that connect to your phone that might give you a better idea of where the problem lies.

 

[foxhole]

Caustic soda can cause a blockage, it’s suitable only for clearing grease as it create great heat but if not dissolved completely can leave solids in the pipe work.(Generally used to clear kitchen drainage).
Have you tried lots of boiling water down it? 5-6 kettles at least might help .
Do you know if long radius 90’s were used?
Plunger used immediately after boiling water may also help .

 

[Mike13]

Hi, from memory they are glued, sharp 90 bends, and sunk into the wall most of the way. I will try a heap of boiling water to see if that helps.

 

[Mike13]

It is a brownish colour, definitely a gel, as if I rub a bit around in my hand it collapses into a watery mix. but getting something to mechanically disturb it past those bends will be tricky. with the trap cleared I have some time to find a solution to moving the rest, but still need to try and work out what is causing this, as it is the second or third time this sink has blocked up. The hairs that find there way down seem to bind the gel quite well, and make it harder to shift!

 

[JohnD]

Buy a sink plunger and some Washing Soda Crystals. Sodium Carbonate. Also sold as Soda Crystals. On sale on the shelf with washing powder and fabric softener. It dissolves soap sludge, grease, and similar deposits. Instructions on the pack.

https://www.dri-pak.co.uk/cleaning-products/soda-crystals/

(note the name. It is NOT caustic soda, which is more dangerous.)

 

[foxhole]

Lots of mechanical clearing devices designed to clear that type of blockage .
https://www.cef.co.uk/catalogue/pro...VcmHmCh2UpA3pEAQYAyABEgKXiPD_BwE&gclsrc=aw.ds

 

[JohnD]

I got a big hand pump, which I think is better than a plunger.

 

[foxhole]

I got a big hand pump, which I think is better than a plunger.

Pumps fine as long a push fit fittings haven’t been used .

 

[lostinthelight]

The gel like coating is Bacteria feeding off fats from soaps , human body etc. Sometimes you can see its frilly edges of the coating with a good light if the trap water is clear . Ive not come across a snake that will pass through a 32mmm tight 90° .

 

[Harry Bloomfield]

The most thorough method.....

If you can, disconnect at the far end of the pipe, usually outdoors. Block the end completely up so it will hold against water pressure, up to where it joins other pipes. Now fill entire system up with a mix of strong bleach and water/ dissolved soda crystals, until level comes up above plug hole in sink - hot water will work faster.

Leave it over night, then carefully remove what ever you used to block the pipe end, expecting a lot of mess and water to exit at high speed. You pipes should end up spotlessly clean inside.

 

[Mike13]

Thanks for all the replies. I think there is a single push fit under the bath, will double check over the weekend, so I suspect the only reasonable plan I have is Harry Bloomfields idea of leaving it to soak in hot bleach and washing soda (Sodium Carbonate). the service space available meant the pipe had to have tight corners, but the job was done about 20 years ago, so it has done quite well.