Sulphuric acid or sodium hydroxide to unblock the pipes?

Jonny69

Jonny69

Jonny69

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The pipe that drains the bath slowly blocks in our rented flat. Basically there's not enough drop on it and it silts up and eventually blocks if we don't periodically run some drain cleaner down it.

It's expensive buying it in the supermarket and I've noticed it's just sodium hydroxide which I can buy much cheaper in quantity and mix it up myself. However, when the pipes blocked completely once the plumber used strong suphuric acid. I can also get this in bulk but it was very smelly.

What are the pros and cons of each and any reason why I shouldn't go for one over the other? It's a plastic bath with chrome fittings and the old soil pipe is iron. Changing the plumbing is not an option due to renting, crazy landlady and shared drainage with upstairs flat.
 
I'd suggest getting a health risk assessment. I suspect that alone will stop you getting the sulphuric acid option.

Both have risks. Any way you couldn't just change the pipes? Might be expensive for a one off but solve the problem, don't cure symptoms.
 
No chance of changing the pipes. The landlady is going to be gutting the flat when we buy our own place and it's a massive job because all the flats share the same pipe. Disconnect our waste pipe (or block it up) and upstairs' waste water comes flooding into our flat. Ask me how I know that...
 
I used some drain stuff for my shower when i moved into my [horror] RENTED [/horror] house. It was from the supermarket but i dont recall it being particularly expensive to worry about. Its probably gonna be hair anyway so whatever works best on that, both acids will do the job.
 
It's £3.50 a pop every two weeks though, while straight NaH is about £3/Kg and 1Kg will do about 4-5 applications.
 
Sulphuric acid is more likely to give off nasty fumes (all sorts of horrible sulphur compounds) than sodium hydroxide.
 
Johnny,

Is it wise to be trusting you with such substances like Sulphuric Acid & Sodium Hydroxide?


Who knows what havoc you will manage to wreck with them \o/
 
Ben M said:
Sulphuric acid is more likely to give off nasty fumes (all sorts of horrible sulphur compounds) than sodium hydroxide.
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We spilled a load of sulphuric acid in a science class at school, it hurt to breathe for a good few hours :o
 
Either would work. Don't try both together though

You can also make NaH quite easily which may make it cheaper.


Neighter are particualrly dangerous if well used. if the Sulphuric acid is too strong dilute it otherwise it can burn through the peipe if left too long.
 
i assume you mean NaOH - NaH would be a bad thing to put down a drain!
i would use sodium hydroxide (and i do) as it doesn't attack metal - sulphuric acid is a bit riskier (comparatively speaking its also a lot more dangerous)
 
aardvark said:
i assume you mean NaOH - NaH would be a bad thing to put down a drain!
i would use sodium hydroxide (and i do) as it doesn't attack metal - sulphuric acid is a bit riskier (comparatively speaking its also a lot more dangerous)
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Yup, my bad. It's been a few years since chemistry class :D

It was the metal pipe that concerned me because I know sulphuric will attack an iron pipe and it would be bad if I went through that. I think my mind is made up :)
 
the sulphuric stuff plumbers use is 95% pure so don't dilute it too much. use rubber gloves and make sure it doesn't splash on skin, eyes etc.

By the sound of your post your using ltrs of the stuff. pour about a cupfull into the drain and leave for about 10 mins then add a cupfull of water and leave for a further 10 mins.

You could always go the old fashioned route and buy a plunger, fill the bath with water and plunge it while it's draining.
 
KOH for an even faster unblocking ;)
I've used NaOH pellets down an outside drain, I'm not sure that I would want to do that in a confined space
 
Zefan said:
Well it was some sort of acid. It was nasty.
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probably hydrochloric - that fumes and really goes for your lungs, and is probably the only other acid you would use in school anyway.

anyway, i think if there is any metal in the pipes i would avoid acids - true, sulphuric acid doesn't attack metals as much as some of the others but i wouldn't take the risk. sodium hydroxide will dissolve anything organic, like hair and food etc, and if you want you could just leave it soaking overnight - thats what i've done in the past.

infact only yesterday i used NaOH to clean my grill pan - it was so caked in burnt on crap that a night of soaking in cillet bang did nothing (useless rubbish) - a shed load of NaOH and boiling water (very carefully!!!) and its as good as new.
 
Jonny69 said:
No chance of changing the pipes. The landlady is going to be gutting the flat when we buy our own place and it's a massive job because all the flats share the same pipe. Disconnect our waste pipe (or block it up) and upstairs' waste water comes flooding into our flat. Ask me how I know that...
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How do you know that?


(Cant believe im the first to ask that ;))
 
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