Sciencemadness Discussion Board

How to get NaOH from household chemicals ?

metalresearcher - 14-10-2010 at 11:40

In the past you could get Crofty sink cleaner in Dutch supermarkets which contained a large portion of NaOH but that is not anymore in the supermarkets.
So (other than ordering at a chemicals supplier) another way to get NaOH is ...?
I cannot find an easy way on (yes wikipedia is for me one of the best online chemistry textbooks) and googling around does not give me better ideas.

- calcining Na2CO3 ?
- electrolyzing aqueous table salt solution but this requires a diaphragm to prevent mixture of the Cl2 and OH- which is not easy.
- treating Na2CO3 sol'n with CaO (precipitates CaCO3) but I have no CaO.

Does somebody have better ideas ?

[Edited on 2010-10-14 by metalresearcher]

spirocycle - 14-10-2010 at 11:46

would the ridiculous heating of baking soda give you sodium?

if so, heat up a couple pounds of it to what I would guess is 1200ish celsius, and then add to water to get NaOH

psychokinetic - 14-10-2010 at 11:54

That's quite a shame that it has become hard to find.
In my house, NaOH IS a household chemical!

You say you have tried supermarkets, but what about hardware stores? My latest tub was from a store named Mitre 10 Mega (but they are only in NZ, I think) sold as drain cleaner pellets. It's great for using as a reagent, and pretty damned good at cleaning drains.

Contrabasso - 14-10-2010 at 11:56

NaOH is used professionally for the pH correction of the colour developer in process E6 for ---Chrome colour slide film so if you have a pro photo wholesaler near you go and ask. If it goes too acid then the colours go blue so add NaOH solution to keep it neutral. It goes acid with aerial oxidation so an under used system goes blue hence uses a lot of NaOH.

hissingnoise - 14-10-2010 at 12:01


- treating Na2CO3 sol'n with CaO (precipitates CaCO3) but I have no CaO.

You don't actually need CaO - slaked lime (Ca(OH)2) will work as well.

deathmetals - 14-10-2010 at 13:05

I asume from your post that you are from Holland.
I know u can still get it from the "kruidvat" and many other drugstores.
there selled ass "goodsteenontstopper"
its solid NaOH and its says its 99> pure

ScienceSquirrel - 14-10-2010 at 13:33

Have a look at biodiesel suppliers.
Holland is famously green and NaOH or KOH is needed for biodiesel manufacture.
Develop credentials like an address; My Business, Unit XY, My Place, and a letterhead, etc and an underlying business or hobby that requires chemicals.

entropy51 - 14-10-2010 at 14:29

Did someone mention suppliers for home soap-making?

peach - 14-10-2010 at 15:49

You live in North Europe FFS.... it'll be there! Check the DIY stores near the plumbing or adhesives and decorating things.

If that fails, shit.... I'll post you a tub of it that'd knock an elephant out if you threw it at one. Poor ele-plant.

Globey - 15-10-2010 at 06:32

I could order it, but I get all my NaOH (Food Grade) because I also make pretzels with it. I just take baking soda, and stick it in the kiln for a couple of hours. On a bright sunny day and 6X100 CIGS cells, I peak out near 720 watt hours, I can get it still hot enough to reach activation energy and run the endothermic rxn.. The sodium monoxide is just quenched in water (smells ozony at 1st), and Viola, aq NaOH. It's fun making your own stuff from scratch. Sure, it's cheaper/easier ordering, but the satisfaction. I really wish some company would offer a professional ground glass organic set made out of like that Visions corning brown glass. Or something incredibly sturdy/resistant.

peach - 15-10-2010 at 10:06

Unfortunately, the springier & tougher it is to shock, the less resistant it gets to chemicals and such. You just have break some, pay the bills, learn, break a bit more until you develop that gentle but firm touch.

I'd like a full actinic set as well, some of the things I do are potentially light sensitive. But, I'd still need the colourless set as well, because other work has significant colour changes that show up things like overheating from the plate or addition rate. I'll sometime sit for hours staring at the glass, watching the colours, particle sizes and textures change. Reflux iodine is sooooooooo pretty.

We don't have Pretzels like those big doughy things you've got over there; which is odd, because I think they came from Germany and the knotted heart shape was to do with marriage, woe-manc, hugs and kisses. I remember sweating until it was dripping off my arms and making a puddle under me in SC when I was over. So nice to have an ice cold beer and a big salty Pretzel when the day was done. Didn't realize they have NaOH in them. Can you PM the recipe? I'd like to have a go at my own since they're not in the shops.

[Edited on 15-10-2010 by peach]

franklyn - 15-10-2010 at 12:40

If there is nothing new in all this do we really need yet one more thread on it.


Picene - 15-10-2010 at 14:19

While the theory is great. It's not really necessary anymore. There are once again over the counter sources for the stuff.

I'll just leave this here.

[Edited on 15-10-2010 by Picene]

peach - 16-10-2010 at 01:51

I seriously have a 5kg tub of KOH and can buy the bases in 25kg bags if you want one, but you're paying the postage. :P

The weight intervals are 500g, 1kg (I think) packs, 5kg tubs and 25kg bags.

5kg is about £8, a 25kg bag is about £20

Comes as white pellets or flakes.

Considering it's basically.... :D drain cleaner, I don't have any problems bouncing orders of that around; it's not fuming nitric acid or borohydride. Unless you're really interested in making it, it's more worthwhile to buy a bag.

I actually need to buy some more myself, as the 5kg tub is bottoming out from the two or so years of glass cleaning it's done. PM me if you want me to pick some up for you at the same time MR. I'll probably be getting KOH, for it's ultimate cleaning power.

[Edited on 16-10-2010 by peach]

Finally I got NaOH from the hardware shop

metalresearcher - 16-10-2010 at 02:11

I got 2 flasks of NaOH pellets (99%, no drain cleaner) for $6 from the local hardware shop. Drain cleaner contains Al snippets which makes it unsuitable for electrolysis and it is more dangerous in the use it is intended for as H2 gas is released when adding water to it.

So I am going to try electrolyzing this lye for my hunt to Na metal.

IMG_4255.JPG - 23kB

peach - 16-10-2010 at 08:28

Why the heck would you purposefully add aluminium to it, something that's going to violently react and produce a fire / explosion hazard in shipping / storage / on the shelf?

The stuff I've bought for drains is pure white flake or pellet.

I'm willing to bet they say the bubbles help it break up blockages.

The more pessimistic me, the one experienced with how they think, is that people will associate the fizzing with it being more powerful.

The same is true of toothpaste. The colours and bubbles make it seem more effective to the customer.

Add to that, paracetamol outperforms other paracetamol, if it comes in a shiny wallet of tabs - powerful placebo effect. And disinfectants with dyes or perfumes seem more effective to the customer, when in reality, 16p bottles of toilet bleach are far better than the commercial blends.

The list is virtually endless.

Rogeryermaw - 16-10-2010 at 09:25

funny that comes up as i recently had to snake out the kitchen drain. after i got it open i finished the job with some of the draino brand "kitchen crystals". it has "some" NaOH in it but it also has some blue detergent garbage in it and aluminum flakes no shit! perhaps the abrasive effect is supposed to help? i have my doubts. they probably just put other crap in it to stop it being a useful reagent but it definitely had little metal turnings of some sort in it(look like they need a way to dispose of the machine floor sweepings)

peach - 16-10-2010 at 10:03


"What do we do with all this?" "Fuck it.... put it in the draino... they won't notice"

I'm a strong voter on the fizz effect. It is really quite stunning how people will buy inferior, more expensive things for the look of the product. E.g. pre-watered down NaOH draino is MORE because it's in a yellow pack and looks more industrial.

Watering it down is probably a good thing, as most people seem entirely retarded when it comes to using it in a domestic setting, it's on the boarder of being (well, is), too strong for average householders - since it'll burn and blister and go out of control.

The hydrogen thing is odd though. They're going to make it a lot more dangerous. E.g. some of the customers will without doubt be smoking as they watch it work. The pipe will have atmosphere in it, mixing with hydrogen, and they may decide to flick cigarettes in there since it's being cleaned anyway.

Squeaky pop x 10

[Edited on 16-10-2010 by peach]

metalresearcher - 16-10-2010 at 11:16

@peach: Drain cleaner *with* Al snippets in it I am *not* going to use because of the violent reaction you mean.
I started to make an electrolysis cell for electrolyzing NaOH, but I watched this video

which discouraged me from electrolyzing lye. The following isuies arise:

- forming O2 *and* H2 gas which may result in EXPLOSIONS
- narrow temperature range (318-330 C) :above 330 C the Na will dissolve in the lye
- hot lye is VERY NASTY stuff

So face shield, gloves and apron are REQUIRED.

He tells about the 'carbon way' (Na2CO3 + C) which is safer and easier than the eledctrolysis, the only safety issue is the flammability of the oil, unless vegetable oil can be used for capturing Na metal.

psychokinetic - 16-10-2010 at 11:20

Yeah, I'd avoid buying Drano brand. Looksy we put all this useful sounding unuseful stuff in here so you'll buy it.
May or may not contain traces of active ingredient!

peach - 16-10-2010 at 13:37

Sorry, when I say Draino, I just mean the hardware / diy type packs for drains. Being from the UK, I don't really see the actual Draino brand. A habit I should probably ditch soon, lest I confuse many US'ers. I try to pick up some of the US knowns so guys over there will be able to relate to things I say easier, but that may be a bad example.

I've never seen KOH or NaOH with aluminium in it though, or anything other than the base it's self, it's always pure white pellets or flakes. My big tub of KOH is for cleaning, but it's pristine white and I can see droplets of water collecting on it if I leave the lid off for half an hour.

The UK, like the US, is on a big anti-bomb adventure, getting everything off the shelves that can come anywhere near useful for bombs, propellants and so on. The idea of adding something that'll produce something similar to a bomb is against the grain.

Len has already McOwned the NaOH / sodium discussion MR. He's by far ahead of anyone else I've seen trying to do it themselves.

I have some mighty big linear power supplies and will be giving his idea a repeat. I may see if I can get it going with computer power supplies as well. My lab supplier doesn't do the alkaline earths, but I need some for solvent drying, as ripping open batteries isn't exactly economical.

MR, the base I'm talking about it is as pure as the CP grade from a lab supplier. But, if ya don't want it, fine then. :P

Where's that damn pretzel recipe? Are you going to make me google for one and end up with a terrible pretzel?

{Useless or insightful comments on the US versus UK}
LOWes is identical to B&Q (the store everyone in the UK knows), they even have the same colour scheme and shop layout style. The prices in B&Q are astronomical though, not LOW. E.g. I wanted a belt sander today. £300 in B&Q, £130 elsewhere; same model. 10m of cable, £10. 50m of the same cable elsewhere, £15. The UK doesn't have mixer taps as standard on sinks, but why does the US have those nasty carts with only two steerable wheels? Ahhhh.... differences... :D

[Edited on 16-10-2010 by peach]

Panache - 17-10-2010 at 02:00

pretzels, my parents are german, i remember my mother making pretzels as you could not buy them here, its just a stocko whiteflour/water/yeast dough however the trick is the caustic, my mother used KOH from memory, i would ask her for you but she's dead. After making the pretzel (a piece of dough is rolled between the hands such that it develops a long thin taper at both end, this becoming the fat bit and the thin bit is the wraparound bits) they are dunked in boiling caustic solution, sprinkled with salt and then baked, i assume the caustic denatures the proteins in the surface resulting in a chewy delicious shell with a soft center. Sliced and filled with butter, swiss cheese and a decent ham whilst still hot from the oven is the best imho.
The fable goes that a cleaner in a bakery accidently dropped a tray into his freshly prepared floor cleaning bucket (caustic and water) however fearing the wrath of the baker he pulled them out and placed them back on the tray and the baker baked them, by the time they were finished the cleaner, sick with worry and fear admitted to the baker his mistake and the rest is history.

woelen - 17-10-2010 at 02:44

@metalresearcher: Know what you are doing. Electrolysing NaOH for making Na-metal can be done, but the engineering problems are tremendous. Read Len1's article on making Na. Not something which is easily done. Please reconsider your attempts to make Na-metal until you have more experience. What is it that all those starters want Na-metal? There are so many other interesting things to do.

metalresearcher - 17-10-2010 at 03:01

@woelen, I am not a starter and have done (and still do) many other interesting things.
I have experience with high temp furnaces (metal melting) and metal chemistry and I observe the safety measures. I already have made Na by the carbon method but was not yet able to isolate it. So I *do* know what I am doing and realize the dangers of Na metal.
Yet I am reluctant to start electrolyzing NaOH because of the dangers of hot lye so I suspend the electrolytic method. The carbon method is a lot less dangerous for me but still has its dangers because of capturing Na in flammable oil.
Or does vegetable oil work too ?

[Edited on 2010-10-17 by metalresearcher]

peach - 17-10-2010 at 04:57

It's because it explodes when you throw a lump of it in a pond, and starters love dramatic youtube videos, even if they have no idea why they're doing something or what it can be used for. The majority of people after things like that aren't interested in the actual science.

I've heard that story of their creation as well, and now realize why the base is used. What you're saying is... I can have clean drains AND a pretzel to eat at the same time? A win, win situation. I feel like a member of the French aristocrazy.

cnidocyte - 18-3-2011 at 11:01

Quote: Originally posted by metalresearcher  
Drain cleaner contains Al snippets which makes it unsuitable for electrolysis and it is more dangerous in the use it is intended for as H2 gas is released when adding water to it.

Wouldn't Al metal be extremely easy to remove from NaOH? For example why not just dissolve the NaOH in water, filter out any insolubles (which should include Al metal) then boil off the water?

EDIT: I didn't think that through before I replied. -OH ions react with Al metal so a reaction would occur as soon as you dissolved the NaOH. The product of that reaction may be easy to separate from NaOH though.

[Edited on 18-3-2011 by cnidocyte]