zinc cream

[Courtney]

Hi all,

Does anyone have a recipe for making zinc cream? Have a new teacher that would like to make it in a few weeks.

Thanks,
Courtney.

[Judy R]

Courtney,
I have a recipe for barrier cream which uses zinc oxide.
35g zinc oxide
210g petroleum jelly
warm mixture,srirring until a smooth paste forms
Do not use laboratory prepared creams on skin.Possible impurities may harm.

[Lyn]

Making Zinc Cream (Barrier Cream)
42g vaseline (petroleum jelly)
8g zinc oxide

Place ingredients in 250ml beaker.
Heat GENTLY over a bunsen burner until vaseline starts to melt.
As soon as it starts to melt, begin to stir mixture gently. Keep heating gently.
Stir mixture steadily until a smooth paste is formed.
If you want a perfumed cream add two drops of perfumed oil after you have removed beaker from the heat and stir into the mixture.
Students should be able to take the finished product home if they provide their own jar. If you want to make a smaller amount adjust the ingredients accordingly. If the kids don't want it then it is quite useful for the lab. tech. to use as a barrier cream. If you have a concern about any impurities in the cream use beakers which have not been used for chemicals ie. straight from the box and keep these beakers specifically for this kind of practical.
Lyn.

[lizzieb]

We've made zinc cream for the last few years with our Yr7's. To begin with we did it in small glass beakers, but a pain to wash up until we realised that salty water was the best way to dissolve the gunk. Eventually I modified the prac so that each student made their own in a baby food jar, which they could then take home:


MAKING ZINC CREAM
1. In a small glass jar melt
[*]10mL liquid paraffin
[*]2g beeswax
[*]a small piece of wax crayon
Use a hotplate set on a low heat
2. When the mixture is fully liquid, use crucible tongs to remove the jar from the hotplate and place on a heatproof mat.
3.Stir in 4g of zinc oxide powder.
5. When completely cool, put the lid on securely, ready to take home.


I asked teachers & parents to send in clean small baby food jars.
We purchased the basic single hotplates from the warehouse (approx. $20/25 each), 5 of them.
Bought the beeswax cheaply from a local honey supplier.
I weighed out the paraffin and beeswax, and cut up brightly coloured crayons (about a quarter each is enough) - sent this out already set up. The students melted & stirred it with a paddle pop stck, and added the zinc (4g = 2 of our spatulas, heaped).

The kids loved it, and so did I - no washing up!!

They're not doing it this year, and I have heaps of jars leftover, but it's amazing the many and varied ways we've found to use them.

Cheers,

[smiley]

Brilliant - another "end-of-term" whizz bang, no washing up experiment.

Thanks.

[Courtney]

Thanks so much, I'll try those. It will be great to get the kids to use babyfood jars and take it home. Fun for them and great for me!!!

Thanks again!