Does anyone have any experience of using Sodium Hydroxide (Soda Fi) to clear a blocked waste water drain pipe? The instructions are all in Thai. It's in crystal form. I can determine it's necessary to keep it off your skin and not to inhale the fumes, but should you supplement it's usage with hot water? How long do you leave it in the pipe before flushing through etc etc?

All and any advice would be appreciated.

If the drain is blocked - the sodium hydroxide will be stopped at the blockage and eventually will work its way through the blockage if you are lucky. No need to "flush it through" per se.

If it is a sink, for example, pour some down the drain, and add water. When the water in the sink goes down, you will be able to presume that the blockage has been cleared. Hot water is not needed unless you suspect that the blockage is caused by grease.

Be cautious though - as if it is PVC pipe and some of the glue joints are weak, it can eat through those joints, thus causing you more problems.

I personally would try a less potent drain cleaner first - like Draino. Less brutal on drainage pipes.

If the blockage is suspected in a relatively short distance from the drain source, you could also try a plumbers snake. That is capable of dislodging bigger items in a drain that other cleaners won't budge.

Caustic Soda [nasty stuff]. You should put the Crystals down the drain and pour enough water onto it to move the Crystals to the blockage and no further. You wil need to leave them for at least 24 hrs for them to do any good. Keep off skin for sure but more importantly wear eye protection. Its not uncommon for a reaction when the water meets the Caustic . arjay, I work with this stuff every day and would try a plunger first. Fill a sink or the bath with water and give it some elbo grease if its not tree roots or some other problem it should move. Take care, I've got scars to prove how nasty caustic is.

The waste water from the house, sinks, hand basins, showers, etc, and the overflow from the septic tank, all deposit into a sump (manhole) about 1m deep, from there it has to go down a single narrow 1.5 inch PVC type pipe, which drains the waste water under the front garden, under the road and into a gulley across the road. All together a distance of about 10-12 metres, all with very little fall on the exit pipe.

I think the blockage is the result of an accumulation of "congealed/coagulated" washing powder (will using liquid form in future).

I have rodded in from each end, with a flexible piece of pipe a distance of about 3ms, but can't get any further in. So at the suggestion of local builder's foreman, have poured in the contents of 3 (crisp size) bags of Sodium Hydroxide. I would guess about 500gms each bag, and after the second and third ones poured in very hot water, which resulted in lots of frothing and foaming and a gas given off. I have used plastic gloves and immediately moved away after putting in the crystals.

The blockage has reduced, and moved further down the pipe. I have also used a hosepipe, but that comes to a stop, after about 3ms due to it not being sufficiently rigid, and the jet of water isn't sufficiently strong to clear the blockage.

Are you saying, allow a little extra water through, but then wait for the soda crystals to work on the coagulated soap powder and other deposits - they look like scale - over a period of time? Some water is exiting the far end, but not very much or very quickly.

I have 2 bags left, though Doc's comments about the stuff attacking the glued joints of the pipes is a little worrying.

Caustic only works on organic matter. If the caustic no longer seems to be working give hydrochloric acid a go. This may also be bad for your pipes but works much faster and can be flushed through after an hour or so

To give you a further feel to things, the pipe concerned exits (at 90 degrees) right on the very bottom of a 3 foot deep x 1 foot square sump. So access is very difficult and any rod has to be sufficiently flexible to cope with the tight 90 degree turn at the bottom of the sump.

Should I get one more batch of the crystals into the exit pipe and follow up, say a minute or two later, with say half a kettle of very hot water, and then leave the whole thing overnight to stew?

Sounds like a good plan arjay. Buy the way, how old is the pipe??

I suppose about 5 years old. If it did fail completely, it would be a major problem to get at it. It's a foot or two below/underneath an existing concrete surface water drainage gulley, and below electrical wires which enter the hosue underground, it goes under the front garden, under the road and out into a surface water gulley across the otherside of the road!!

It's shame that the bottom of the sump, the exit pipe, and all the pipes that enter the sump are well below the level of the existing concrete lined surface water gulley, otherwise the water could be directed down that instead. However, as I said all the pipes entering the gulley, inc the septic tank, enter at a much lower level than the surface water gulley.

At the end of the day if all else fails you may have to employ a good Plumber. I could put you on to one here, but I dont think you would like the call out fee

I guess what would be really useful would be a "Dyno Rod" type company, with a long flexible rod or jet hose!!

There must be someone in Udon with a long flexible Rod who could help you out

Arjay,

I have one that's about 15 ft ot 4.5 meters long, kind of a light duty one so I don't know how well it will work on your problem. I picked it up at the ground floor shop in Big C for 75 bt. If you don't want to spend the baht you can borrow mine.

Thera are a special nozzle and hose for the high pressure washer that is so far the most effective pipe cleaner I seen... I forgot the name for it but will try to find it. I know my wife had a couple of guys over to fix a blocked pipe last time I was a t work, so it is available in Thailand...

looked around on the net and it is called a pipe cleaning set, it does the works with blocked pipes..

look at this link and you will see what it looks like...

http://www.pressurewashersdirect.com/ca ... =21_90_119

Be really careful if you decide to give the hydrochloric acid a try. If it mixes with sodium hydroxide while they are both concentrated you can get a pretty strong reaction. Just flush the pipe with water before adding the acid.

I don't know if you can find it in the plumbing shops here but sulfuric acid is another strong pipe cleaner. It's even stronger than hydrochloric acid so it's also somewhat more dangerous. Rubber gloves, eye protection, long sleeved shirt, etc. Again, flush the pipe well before using. Let it sit for a while after you pour it in - half hour or so - and then flush again. Good stuff but a little dangerous. Here's a PDF on how to use it: http://www.jcwhitlam.com/pdf/NW-SPEC.pdf