Just checking my figures...

Let me see, 1L of 50% benzalkonium chloride will make 100L of 0.5% or 400L of 0.125%. Does that sound right? Hope it?s enough...

Most hand steriliser foams seem to be in the order of 0.1 to 0.13% BC

Tim

Looks OK, except that benzalkonium chloride isn't very effective against COVID-19, apparently. I've come to the conclusion that a lot of the antiseptics that claim anti-viral properties, whether in bottles for dilution of sprays for spraying around the toilet or wherever, rely on their anti-viral effect because they're alcohol based, and the benzalkonium chloride they contain just kills the bacteria.

Correct.

Go for a hand wash with 70 - 75% IPA (perhaps with 1 or 2% hydrogen peroxide), and you won't be disappointed. In the bog or bathroom fresh bleach is really what you want. Cheap and effective.

I have cans of IPA in my drinks cupboard. Nice with a curry! :-)

LOL! I used to see many adverts for "India Pale Ale" in London in the

As you say, it doesn?t seem to be particularly effective. I?ll probably just keep some round in places where I can?t get to hand washing facilities until I can get alcohol hand steriliser.

I wonder what the thickener is used in the alcohol gels? Could you use meths with a thickener and some moisturising agent?

Tim

Glycerol:

Theo

Bleach, diluted down a bit?

You can get surgical spirit OTC in chemists or from e-bay

But more seriously, I hear that Brew Dog are going over to making sanitiser for the moment (presumably from industrial alcohol).

glycerine and polyacrylic acid are listed in mine.

Methylated spirits contains methanol and dermal absorbtion is a possibility, but I can't find anywhere that states absolute values.

Been using it for years on electronic components and the like though.

I've never been sure if it's 'a good idea' of getting some of these solvents on our skin as I understand we can absorb them into our bloodstream? Now, whilst it's not unknown for me to have some alcohol in my bloodstream, it's generally what I've swallowed rather than absorbed through my skin. ;-)

So, I think I have some rubbing alcohol here somewhere and I know I have some IPA but is it ok to wash my hands in either (and how well would it work when applied 'raw' against Covid-19)?

We have some 'Medex Hand Sanitiser' here but looking online it seems to be only 40% alcohol?

She has and the fumes off most brands make me cough. ;-(

The one she has that doesn't is 'Hydrating Cream by Sainbury's' so maybe I'll borrow some after all this hand washing / sanitising.

Cheers, T i m

What percentage is 'std' IPA, if there is such a thing? eg, A mate bought quite a bit ages ago and decanted some for me for general use. (general solvent / removing labels etc) so I have no idea what strength it is?

Do I understand that bleach 'goes off'? We aren't fans of the smell and aren't sure how good it is to dump too much into the environment so may have some old stuff kicking about?

Cheers, T i m

Poor the bleach down the lavatory. It's what most people buy it for in the first place.

michael adams

...

So it's no use for anything more positive?

Why? To bleach white the stained calcium buildup rather than removing it?

Cheers, T i m

Yes I use it diluted as a hand cleanser and I actually like the smell as it reminds me of the swimmming pools of my youth. The sense of smell above all others can be highly evocative. I haven't been near a swimming for years now so I don't know if they still smell the same. I've had all sort of chemicals on my hands barring caustic and acids over the years and have never experienced blisters or rashes. Maybe I'm lucky and have naturally impervious skin.

Bleach kills all the germs hidden around the bend in the lavatory which if left untreated will creep up the sides and attack you when you least expect it. Allegedly.

michael adams

...

I don't think that 'washing your hands' in it is quite the right phrase. It rather suggest you are considering pouring it over your hands as from a running tap. It would be OK to do that, but rather wasteful. You just need to wipe your hands thoroughly with a cloth made moist with it.

'Rubbing alcohol' can be either surgical spirit or IPA (isopropyl alcohol or isopropanol).

Both work best when 'raw' as you put it, i.e. at their most concentrated. COVID-19 has an oily surface made of lipid (fat) molecules, and rubbing alcohol of either composition will disrupt that surface and disable the virus, in just the same way as they degrease other oily surfaces.

How would you make it less than 'raw', other than diluting it, which would make it less effective?

IPA on its own is 100%. Hand washes often contain a gelling agent. I've seen Aloe Vera gel suggested, but synthetics are also used, e.g polyacrylates. The gelling agent will consist of a dry powder which is then dissolved in water to form the gel, in just the same way you make jelly from crystalline gelatin and water. So if you have a hand sanitiser gel, it will have quite a lot of water in it from the gelling agent. Too much gel added to the rubbing alcohol will lower the alcohol content of the mix to below the minimum value of 60% recommended for use against COVID-19.

Bleach can lose its strength if the top is left off for any length of time, or if it's an old bottle that's been opened many times. Household bleach is a solution of sodium hypochlorite, NaOCl and salt. It's made by reacting chlorine gas with caustic soda solution. 2NaOH + Cl2 <-> NaCl (common salt) + NaOCl + H2O. The reaction is reversible, and if the top of the bottle is left off, the chlorine evaporates away and the bleach loses its power.

I would think 'Milton' is quite effective against COVID-19, as it's little more than dilute bleach with extra salt.