Making GAK

Here's a fun science experiment - making your own GAK (aka flubber).  Lou came home from a play group the other day and had made this stuff there.   I thought it was so fun, I looked up the recipe and found it here.

All you need are 3 simple ingredients:
  1.  Elmer's glue (4 oz. bottle)
  2. Borax - I found mine at Walmart near the laundry detergents.  You only need a small amount, but a box only costs around $3.
  3. Water
You can use food coloring or paint to color it, but we just used markers.  We even used the washable kind and they worked just great.  Here's what to do:

  • Pour entire contents of 4 oz. glue bottle into a large bowl.
  • Fill the empty glue bottle with water and shake, with the lid on of course.
  • Pour water into the bowl with the glue.

Stir water and glue mixture.  If you want to add food coloring to your GAK, you would do it now.  We chose to color ours afterwards with markers.

  • Mix together 1/4 cup water and 1/2 tsp. Borax - it's ok if the Borax doesn't dissolve completely.
  • Slowly add the Borax mixture to the water and glue mixture while stirring.  The mixture will start to change immediately from a liquid to a polymer.

This is when it's time to take the GAK out of the bowl and knead it a little with your hands.  If you want your GAK to be a little more stiff than gooey, just add a little more of the Borax and water mixture.  Then you are ready to play!

We colored our GAK with markers,

cut out shapes with cookie cutters,

and rolled it out flat.
They were also able to roll it up and bounce it, or just stretch it.

Then we tried to blow bubbles with the stuff.

Lou showed us how to do it by wrapping a small piece of flubber around the end of a straw and blowing into it.

Maisy blowing her own bubbles.


By the end,  Lou's portion of GAK had turned brown from all the colors that had been added to it.  Lou was quite upset for a little bit about this - but she did know from the beginning what would happen if she kept adding all sorts of different colors to hers.  It became fun again when she realized she could make a chocolate mint cake out of it.

I need to mention two things. Mina got it on her clothes a couple of times and it washed out completely.  I did use washable glue as well as washable markers so I'm sure that played a factor. Also, I don't recommend this project for a child that has a tendency to put these types of things in their mouth, given the ingredients.

When playtime with your flubber is over, make sure to seal it up well in a zipper lock bag. It should stay moist enough to play with time and time again. 

In response to a comment about the concern for a child's safety using Borax, I must first say that safety for our children is my first priority. After seriously researching the safety of using the Borax I found that it does have a low toxicity level, and I have come to the conclusion that it's OK for children old enough to understand not to ingest the stuff. And when I say ingest, I mean that a child would have to eat the entire batch of slime to experience adverse effects - it actually takes a full teaspoon. The same effect could possibly come from a child who ingests bubbles meant to be blown - after all they are made with soap. Also, a child should wash their hands after playing with this concoction as it could possibly cause skin irritation if not washed off.  My children have played with GAK three times now and we have yet to experience anything adverse - it was kept out of their mouths and hands were adequately washed after play.  Borax should be treated like what it is - a cleaning agent similar to laundry detergent or other household cleaner.  It is safe when used under adult supervision

Boron, the mineral found in Borax, is also used as a health supplement. It is only harmful in large doses - just as most other minerals, for example table salt. However, it is up to you as a parent to decide whether or not you think this is safe for your child.

I think this article was most helpful in answering my questions because there is a lot of contradicting information out there.   


  1. I can't believe how cheep that box was. I need to do this very soon.

  2. I thought I had heard that Borax isn't safe for children to handle.

  3. This post is awesome! I love all of the stuff you did with your GAK! I loved seeing your girls drawing on it with marker. So cool! I pinned it to my board on Pinterest.


  4. We also make our own laundry soap with borax as one of the ingredients. In fact, that's actually one of my seven-year-old daughter's chores. She makes a batch about every month, we make gak all the time, and we STILL have a ton of borax left in our box!

  5. We did this with our preschoolers when I taught preschool! I am so glad you stopped by and shared it with us on The Sunday Showcase



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