The great slime debate: to borax or not to borax?

Has your house been hit by the slime craze yet? If it hasn’t, I see it in your future very soon.

Buddy came home from preschool asking to make some slime a few weeks ago. I’m a glutton for punishment, so I happily obliged. I knew enough about slime to know it was easy to make. But I also knew there’s been some major controversy behind slime-making methods.

In case you’ve been living under a rock, there are a few different ways to make slime. But one of the most popular includes using Borax. Borax is often used as a natural cleaner but there’s some debate on whether or not it’s safe.

Now, before you get ready for a fight, I’m not here to sway you one way or another. Since I have 2 kids, I figured it was worth it to try slime 2 ways. Buddy made Borax slime and Turtle made non-Borax slime and then we compared them to see which was the best to make (or if it’s even worth making at all).

Slime 2 Ways

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Borax Slime

This recipe was taken from The Ultimate Book of Kid Concoctions.

Materials:

Recipe:

  1. Mix 1 cup of water and 1 cup of glue together in a medium bowl.
  2. In a second bowl, mix 1 1/3 cup of warm water with 4 teaspoons of Borax.  Stir until the Borax is completely dissolved.
  3. Slowly pour the glue/water mixture into the Borax solution.
  4. With your hand, roll the the glue around a few times until it starts to stick together.
  5. Lift the glue out of the water and start playing.

The reason this works is because glue is made of synthetic polymers, which are linked together by the Borax solution making it super stretchy and slimy. To learn more about polymers, check out these activities.

Saline Slime

Materials:

Recipe:

Mix the glue and baking soda together and add the saline solution a little at a time until slimy. Too much saline solution will cause your slime to break.

In this recipe, the saline solution is what is linking the polymers in the glue together. The baking soda gives the slime some density. It’s worth noting here that saline solution does have boric acid and sodium borate, which are the same chemicals Borax. I’ll be honest here, I don’t really see much difference between giving your kid saline solution vs. Borax other than the saline solution is already diluted. But if that dilution step is what worries you, by all means use saline.

My two slime

Pink slime made with saline solution Blue slime made with Borax

To Borax or not to Borax?

I, personally, did not have any issues using the Borax in making our slime. And I think used properly and in moderation it is a safe substance. But I strongly urge you to do your own research and use your best judgement before handling. You know what your kids are capable of. If you don’t trust that they will keep Borax out of their mouths, don’t use it. But if that’s the case, you probably shouldn’t give them contact lens solution, either. To kick off your research, here’s one article I found interesting that you might want to start with.

If you decide to give the Borax recipe a go, keep in mind that it’s important to pour the glue into the Borax solution and not the other way around. Buddy made his first round the wrong way and it turned out too dense to handle. I’m no scientist but my hypothesis as to why this happens is because if you pour the Borax solution over the glue, it’s difficult to fully incorporate the solution in the glue. This means less water for your slime, which is a key ingredient.

That said, the biggest difference between the two slimes was density. The saline solution slime was denser than the Borax solution, although I think that’s because we added too much saline. But I didn’t mess with it because both kids really liked it at the consistency it was. Borax slime felt slimier, so it had that gross factor. But it didn’t hold the interest of either of my kids for long.

The saline-solution slime kept their attention slightly longer because it was less sticky and more malleable. So if you’re at all concerned about using Borax in your slime recipe, the saline-solution slime is a stellar alternative. You still need to supervise, though. Saline solution can cause stomach irritation or diarrhea if you ingest enough of it.

Ultimately, I think my kids prefer play dough. We have just as much fun making it (they like cooking on the stove top) and it holds their attention much longer when we play. I’m also a lot less concerned with the mess play dough makes than slime. But that’s just me and my craziness.

Life skills learned from slime

No matter which recipe you choose, take some time to let your kids experiment in their mixing. Try making smaller samples and see what happens if you use more/less water. Add extra saline solution in the non-Borax recipe and see what happens. Does the type of glue matter? These tests may destroy your kitchen but will spark some good discussions about experimentation.

It’s also a good lesson in following directions. If you want perfect slime, you need to read the directions and follow them carefully because doing one step out of order could mess it up. That’s why chefs use recipes.

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What’s your favorite slime recipe?