Thursday, June 26, 2014

Rainbow Cake Soap Fun

Days ago I saw this link on Facebook about making a rainbow cake loaf, it got me very excited!  Normal people see cake, I see soap!
This is a very time consuming project, it needs to be made in multiple stages, actually very similar to baking a cake and then decorate it.  To start, I went to home improvement store and bought a sheet of plastic corrugated panel, it's lightweight but non stick and not that hard to cut.  I made myself a cheap mold so I can make a skinny loaf of soap.
I used banana blended in coconut milk to make the "cake."  The speckles from banana is perfect for imitating an actual cake don't you think?
The next day I unmolded the soap and made some whipped soap for icing to cover all 5 sides.  Curious about what whipped soap is?!  Well, I got it covered, see this post about making whipped soap: How to Make Whipped Soap
The reason I used whipped soap for icing is so I would have plenty of play time to get it all smooth and pretty.  And whipped soap texture is the closest to the real texture of cake icing or whipped cream.  This is the time consuming part.  After slapping on the whipped soap with a knife I started using a silicone scraper to smooth all sides out back and forwards many passes.
The last stage is the color drizzles.  This is the part that went crazy on me.  Splitting a very small batch of soap into 7 colors is not a good idea.  I was not able to keep the soap batter fluid enough, it was more like icing than syrup.  Instead of drizzling on the "cake" top, I had to improvise and scoop each color soap into a sheet of saran wrap each, scrunched up all sides, poke a tiny hole at the center and squeeze it like a pipping bag.
They look like rainbow worms crawling all over my cake soap!
Here is the cut to see how it looks like inside.  Why not make a white cake inside just like the inspiration photo?  Well,
 my design concept is you only get to see a piece of rainbow right after a stormy sky, never see a rainbow in a perfectly bright sunny day!


  1. I think you did a fabulous job!! Looks like real cake.

  2. Wow!!! this is truly amazing. You have so much patience. Can you tell me whether the banana gives any scent to the finished soap? Do you think it adds to the moisturising and lathering qualities? I love working with food in soap, but haven't tried banana yet. Thank you for your great blog and all of the information and inspiriation.

    1. Banana doesn't give soap any scent, and it oxidize very easily hence the brown speckles. Banana has very high content of sugar, it will produce tons of thick lather. However, bit can heap up your soap fast because of the sugar, so if you like to gel, watch it to avoid over heating, it can volcano.

  3. This is the most fabulous soap I have ever seen! Great!

  4. So cool! I love how it turned out and the reminder that rainbows follow the rain. Thanks for making me smile!

  5. OMG, this is such a beautiful soap!

  6. Love how you think and create! Keep up the whimsy!

  7. Great look! Loved the concept. You got it !