Maths Help Please (Hand Sanitiser Recipes)

Raymond Lin · 24 Mar 2020 at 14:28

WHO recipe has hydrogen peroxide in theirs, is that rest necessary considering 75% of the content is alcohol.

Fourstar · 24 Mar 2020 at 14:38

Raymond Lin said:
WHO recipe has hydrogen peroxide in theirs, is that rest necessary considering 75% of the content is alcohol.

This is probably more relevant to larger scale production, storage and distribution where conditions are less sanitary. No DIY recipes I came across include it. The guide says it is not an active ingredient for sanitising.

Hydrogen peroxide: used to inactivate contaminating bacterial spores in the solution and is not an active substance for hand antisepsis.

Raymond Lin · 24 Mar 2020 at 14:49

Fourstar said:
This is probably more relevant to larger scale production, storage and distribution where conditions are less sanitary. No DIY recipes I came across include it. The guide says it is not an active ingredient for sanitising.

that’s what I figure, too much peroxide will bleach the skin which isn’t good...their percentage is 4% which is tiny, 40ml in a total 1L solution meaning 50ml bottles 2ml of hydrogen peroxide...that’s practically an impossible amount to measure outside a lab with household equipment accurately. In fact I don’t even know how I can measure 40ml.

TrannyBill · 24 Mar 2020 at 14:57

Raymond Lin said:
that’s what I figure, too much peroxide will bleach the skin which isn’t good...their percentage is 4% which is tiny, 40ml in a total 1L solution meaning 50ml bottles 2ml of hydrogen peroxide...that’s practically an impossible amount to measure outside a lab with household equipment accurately. In fact I don’t even know how I can measure 40ml.

Get a bottle of kids medicine.
Tend to come with syringes in the range of 2.5 to 10mL

NVP · 24 Mar 2020 at 15:19

No just need the math on how many pockets I need to empty, if each pocket contained 0.23g of lint, to make half a roll of 1 ply toilet roll

Ryan-3 · 24 Mar 2020 at 15:34

TrannyBill said:
Edit: I see you have corrected while I was replying haha

Apologies. Late night and maths don't mix well with me I'm afraid!

Feek · 24 Mar 2020 at 21:24

I've had this for years, every so often I decant some into a smaller and more convenient bottle and use it as cleaning fluid.

No idea what percentage it is - Does anyone know? I also have glycerin. If I wanted to make [say] 200ml of a substance suitable for hand sanitising, what percentages of each should I use?

Ta.

jpaul · 24 Mar 2020 at 21:34

usually it says what the purity is , last one I bought did, but since it doesn't say it's rubbing alcohol, or diluted, must be high 90s

1 x SHL 1 Litre (1000ml) Isopropanol Isopropyl Alcohol 99.9% (IPA) CHILD PROOF CAP £6.69
don't know where these folks are picking it up for peanuts

Deluxe1 · 24 Mar 2020 at 21:41

muon said:
I also have 4 litres of 99% IPA. Have it for cleaning electronics and computer parts. Always wondered if this was possible. How did you get glycerol?

I got a litre of glycerine a month or so back before everyone went nuts you can still get it on the rain forest.

240 ml isopropyl alcohol 99%
15 ml hydrogen peroxide 3%
5 ml glycerin
60ml Water to make a total of 320 ml

Feek · 24 Mar 2020 at 21:57

Deluxe1 said:
you can still get it on the rain forest.

If you mean Amazon, say Amazon.

b00merang69 · 24 Mar 2020 at 22:00

I buy 99% IPA for PC use and the Yanks use something called Rubbing Alcohol for medical cleaning etc which is the same but diluted to 70%.

Seem no longer in stock, I got 1L left.

SHL BRAND ISOPROPANOL IPA Isopropyl Alcohol 99.9% Pure (1 Litre) 1000 ml

Rickyw88 · 25 Mar 2020 at 07:59

I picked up some 70% stuff months back to make a record cleaning solution. I tried to add some aloe Vera gel to make it 60% but the gel wasn't pure and it just went all stringy

I might just use it as is and use the gel to keep my hands from drying out afterwards

Feek · 25 Mar 2020 at 13:06

Deluxe1 said:
240 ml isopropyl alcohol 99%
15 ml hydrogen peroxide 3%
5 ml glycerin
60ml Water to make a total of 320 ml

I can get some 6% hydrogen peroxide but not 3%.
Half the amount used and increase the water accordingly?

Deluxe1 · 25 Mar 2020 at 13:41

Yeah that would be ok.

adam cool dude · 25 Mar 2020 at 13:52

TrannyBill said:
Get a bottle of kids medicine.
Tend to come with syringes in the range of 2.5 to 10mL

I like the way you mention it that you can just walk into a supermarket and buy some Calpol. Out everywhere.

WantoN · 25 Mar 2020 at 14:01

Just wash your hands. It's just as effective as sanitiser.

jpaul · 25 Mar 2020 at 14:02

you can do it all by weight instead, gram accurate scales .... glycerin's viscous (fixed density?)
they're miscible or is it going to separate over time too, I guess the pro stuff has a stabiliser.

edit : not outside the house !

Feek · 25 Mar 2020 at 14:13

jpaul said:
you can do it all by weight instead, gram accurate scales

I was wondering about doing it that way as although my scales which go down to 1g may not be entirely accurate, at least all the measurements would be equally inaccurate and therefore in proportion to each other.

But I don't know what the viscosity of IPA, hydrogen peroxide and glycerin is so I don't know what each of them should weigh!

/edit - this looks to be a handy tool for working out weights.

188g of IPA
11g of 6% hydrogen peroxide
6g of glycerin
75gm of water

TrannyBill · 25 Mar 2020 at 14:21

adam cool dude said:
I like the way you mention it that you can just walk into a supermarket and buy some Calpol. Out everywhere.

I've no idea, haven't been to a large supermarket in over a month I'm affraid.

firstborn · 25 Mar 2020 at 14:35

WantoN said:
Just wash your hands. It's just as effective as sanitiser.

I would further advise that if you can't do the maths then you shouldn't be doing this in the first place.