Gurgling sink - caustic soda precautions

[Potatan]

Hi all,
My kitchen sink plughole gurgles when the washing machine is emptying. Also, after I have used the washing machine or even run some water down the sink, the plughole will have a little "glug-glug-glug" about every 10 minutes for an hour or so.

They both empty into a fairly long waste (15' or so) with not much of a drop. The suspicion is that the drain outside is blocked or clogged because
a) it has blocked before
b) the house was built in 1760 and the drains are fairly old

I cleared the blockage in the outside drain last time with caustic soda granules, mixed with water - however, the drain is very awkward to get to.

So, my question is, can I mix up the caustic solution in the sink and let it empty into the drain from there? The sink is a Belfast, with a chrome waste, and a chrome trap underneath, attached to plastic pipes.

Would it be safe (i.e. not damaging the sink or pipes) doing it this way? If it is, it would have the added benefit of clearing old soap etc. from the waste pipes as well as the drain, and then I could incorporate it into a regular routine with no hassle.

Thanks in advance

 

[kevplumb]

don't see why not i do

 

[breezer]

so long as it is hot water, use cold and caustic soda has been known to turn solid

 

[felix]

Caustic soda, aka sodium hydroxide or NaOH, is vicious stuff. It will not attack chrome or plastic. It will attack aluminium and anything organic with a vengence. It is also one of the few chemicals that can attack glass - but only very slowly. It turns grease into soap - actually that's how you make soap - so it's good for clearing some, but not all, drain blockages.

I can see one problem with putting HOT NaOH down your sink. By the time it reaches the other end it will have cooled a lot. At some point it will crystallize out and - as Kevplumb says - it can even turn solid; the water becomes part of the crystal structure.

I assume your waste pipe empties into some kind of drain gully, in which case the gurgling you can hear is due to the pipe outlet being below water level in the gully. My first line of attack with a blocked gully is always mechanical rather than chemical. Lift the grate and scoop out the muck!

WARNING: If you're going to mess around with hot, concentrated NaOH you need rubber gloves and goggles. Add the crystals to the water, NEVER the other way round!

 

[breezer]

as Kevplumb says - it can even turn solid;

polite cough.


as for the hot water , that is what the instrcutinos said

 

[felix]

Sorry breezer, I stand corrected. It was a late night.