I am currently having trouble with a practical called Silly Putty from the Heinemann Science 2 book.
The materials include 20ml of Borax Solution and 25ml of PVA glue and add a few drops of food colouring.
My problem is the Borax solution seems to make it very runny.
The Borax that I make is 10ml Of borax and 250ml of distilled water and I am having to add Borax powder to the mixture. Unfortunately the putty is not a good consistency, it is either very runny or turns very hard.
There are a couple of good slime recipes in 'The Laboratory - a science reference and preparation manual for schools' page 87 if you have a copy. If not let me know and I can attach or fax a copy to you.
The Silly Putty expt in "Science Focus 1" uses saturated Borax solution and we've never had a failure. So - add equal quantities of PVA and water (eg 2 teaspoons), mix thoroughly and then add equal amount of sat. Borax soln (eg 2 teaspoons) mix thoroughly and then rinse your lump of silly putty under water. and voila!
I get the students to do this in specimen jars as it saves having to wash up beakers and it gives them a container to take it home in.
Really fresh PVA glue helps - and if you can find Crayola glue try a bit of that. There must be something different in the glue recipe in Australia, because it turns out differently. All my website findings mention "Elmer's Glue", which must be an Americanism. WE have also had a variety of results using glues from "Warehouse" or "Crazy Clarks" or whatever the local version is of that.
We have used PVA glue and 4% borax in 20:5 ratio and works well, but if you want PVA sol, make up 4% soln, heat to about 90oC to dissolve and cool. Make up 4% borax and use 50 ml polymer solution with 5-10ml of borax. Use plastic cups and paddlepop stix and that way you have no washing up.
lada
I have also found that not all PVA glue is the same and a test run is advisable in advance.
Start with 10ml of 4% BORAX SOLUTION AND 50ml of 10% PVA.
Some PVAs I found are better at 50%. I prefer to increase the glue concentration than the borax.
Then write it on your glue for next time.
Hi Laurina. You said you used 10mL borax to 250mL water. I'm not aware of liquid borax. Did you mean 10g? I think that 4%, so you should be right. It takes a bit of dissolving in cold water. I dissolve it in half the quantity of boiling water, then add cold water. I always use Aquadhere (unfortunately quite expensive), as I've found it to be one of the few PVA glues that works really well. The teachers have complained about some of the other brands I've put out. If your silly putty is still too runny, just add a little more borax solution.
Good luck!
I'll fax that recipe to you as soon as I can get to the office today.
Sorry, I've been on a few days' long sevice leave and only just catching up on the latest posts.
Laurena
