Caustic Soda

What's the difference ?

Seeing some of the people who drive while using them, are you so sure ?

One more point, NaOH solution is very good at "creeping" out of containers. Don't store it in liquid form unless it is in a securely closed container

I've been using quite a lot of it recently in the biodiesel process - I've found storing it in a plastic barrel with airtight lid and clamp helps a lot in keeping the moisture at bay.

Hygroscopic materials absorb water from the air.

Deliquescent materials absorb so much that they'll dissolve in it. Relatively few hygroscopic materials do this.

Conventionally, deliquescent materials aren't described as hygroscopic (i.e. using the term hygroscopic implies that it isn't actually deliquescent)

-- Die Gotterspammerung - Junkmail of the Gods

On Mon, 27 Oct 2003 22:21:43 -0000, "stuart noble"

Isn't uk-diy marvellous

font of knowledge with dictionary thrown in ...

cheers

Fair point. Think of it as evolution in action.

Plastic covers a wide range of materials##

It certainlty degrades the sorts of plastic bristled bog/dish brushes you buy.

You are taking the mickey. I claim my five pounds. ;)

PoP

Tell me about it. I bought a couple of bottles of Screwfix drain cleaning solution. Put them on my shelf in the garage until I needed them. Fortunately a couple of weeks later I had a need to go routing thru the shelf contents - and found that this drain cleaner was seeping out of the sealed plastic bottles.

Immediately cleaned our drains so as to get rid of it, although the drains didn't need cleaning.

PoP

stuart noble

Yes those are usually polyethylene handles and nylon bristles. Both of them susceptible to NaOH.

I have some of that Oxygen based cleaning powder. Vanish Oxy Action is one brand, but not the brand I have.

On both tubs they say you shouldn't store it once you mix with water, as it will continue to produce oxygen.

Ok I ask, why not? What's wrong with it continuing to produce oxygen?!

same as paracetamol (OD) then

It'll burst a sealed container.

If the action relies on it producing oxygen, then having this useful reaction go on in storage will mean that it'll have run out of steam by the time you come to use it.

-- Die Gotterspammerung - Junkmail of the Gods

Interstingly enough, in an attempt to clear a blocked drain a while back, I bought a plastic tub of caustic mixed with flakes of aluminium foil out of my local hardware shoppe...

It didn't work and I ended up hiring a long flexable turny thing to grind out several years worth of massage oils and a dead frog from the pipe...

Gordon

Indeed, I once dripped about 20microlitres of liquid buffered phenol on my leg (I was wearing shorts and sitting down). Boy did that hurt, far nastier than caustic.

Peter

When melting (not dissolving) a fish-kettle full of potassium nitrate over a stove, is it safer to use the bluing salts alone, or to make a eutectic mixture with caustic soda and lower the melting point ?

One is a large pan full of a very hot oxidiser (don't stir it with a stick !), the other is a pan full of less hot, but more corrosive, salt.

Gun-bluing steel BTW, not mixing it with sugar.