Introduction: Bathtub Soap Crayons
These bath crayons are easy to make, and most importantly, kids love them! I used a bar of almond soap that was given to me around Christmas, but you can use any white bar soap as long as your kids don't have a skin reaction to it.
Step 1: Ingredients and Supplies
To make these soaps, you need the following:
1 Cup of soap- any white bar you'd like
Food coloring
2 tablespoons warm water
Bowls- 1 for each color you want to make
Cheese grater
Molds- I used empty candy trays, but you could use ice cube trays, cookie cutters or even mold them with your hands if you'd like
Fork- for mashing it all together
Paper towels
Step 2: Grate the Soap
Grate your soap on the smaller side of your cheese grater. Since I was making a set each for my niece and nephew, I doubled the amount and grated 2 cups of soap, which was about half of a fairly large bar.
Step 3: Add Water and Mix/Mash
Add 2 tablespoons warm water for each cup of grated soap you have. It won't look like enough at first, but after you begin mixing, you'll notice it start to stiffen up and become thick. I find it easiest to mash the whole thing together with a fork rather than stir. Keep mixing until you have a thick, even consistency throughout and no soap gratings left.
Step 4: Separate and Color
Separate your soap evenly into as many bowls as you have colors to make. Use your food coloring to dye the soap. I started with 2 drops of coloring per bowl, then bumped it up to 4 each for brighter colors. If you're using the same fork to mix all of the colors, start with the lightest color first, wipe the fork off with a damp paper towel after that color is fully mixed, and move on to the next lightest color. This way, any residual coloring you have on the fork won't dirty your next color. Continue until all of your colors are mixed to your liking.
Step 5: Mold and Set
Firmly press your soaps into the molds that you've chosen. Pop them in the freezer for a couple of hours (or overnight) to solidify.
Step 6: Remove From Mold and Draw!
Remove your crayons from the molds. They're now ready to be used in the bathtub, so color away! Or, you know... give them to your kids.

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19 Comments
8 years ago
It's the soap that leaves a sticky residue on the skin. cheep soap without glycerin (they remove the glycerin to put in more expensive products like lotion.) Or if you have hard water, the soap builds up on the skin very quickly leaving you to feel sticky.
12 years ago on Introduction
just wondering.. does the food colouring make your kids sticky?
Reply 12 years ago on Introduction
I've never heard of it making people sticky. It's possible different brands might react oddly, but I just use the generic grocery store brand and it works without issues. Hope this helps!
Reply 8 years ago on Introduction
you can make your on NATURAL food dyes.
you could probaly look on this website for a key to the colors and recipes
Reply 12 years ago on Introduction
also, does it stain?
Reply 12 years ago on Introduction
I haven't had problems with these staining, either. Just be sure you don't use copious amounts of food dye, and you should be fine.
8 years ago on Step 6
The colour didn't show up once in the tub.
9 years ago on Step 6
These are a great idea. Is it difficult to wash off of your tub?
12 years ago on Introduction
Will the bath crayons melt when they are out of the freezer or are they good to go?
Reply 12 years ago on Introduction
They won't melt, freezing just speeds up the solidifying process.
12 years ago on Step 6
im going to make a project with your idea
Reply 12 years ago on Step 6
Let me know how it turns out!
12 years ago on Introduction
Hey mine got made into a featured article, but it isn't showing up on the front page. Can you help me since I noticed yours is on the front page.
Thanks
Reply 12 years ago on Introduction
Hmmm... I'm still fairly new here and don't know a whole lot about the inner workings of Instructables. Maybe try asking in the forums? Someone there is bound to know. Hope you get it figured out!
Reply 12 years ago on Introduction
I got it all figured now.
Thanks for your help!
12 years ago on Step 6
Aww these are so cute!
12 years ago on Introduction
How do I vote for it in the contest?
Reply 12 years ago on Introduction
You have to wait until the entry deadline passes (Jan. 2). Then you can go to the contest page and vote for as many as you'd like while voting is open. Thanks for your interest!
12 years ago on Introduction
I remember having these when I was younger. I loved them. This is a cool idea.