Sunday, 18 January 2015

Handprint casts (with baking soda clay)

So I may have a teeny tiny obsession with baby hand and footprints... We have done so much stuff with both D and Iz. The only ones I've written about so far are the Christmas cards we made over the last 2 years - I'm not quite sure why I haven't blogged about the rest but over the next few weeks I'll put up posts and pics of all the things we've made :)

First up is actually the latest thing we've done - clay handprints. I wanted to get both the kids' handprints, especially Iz's whilst she's still so little. But there's only a finite number of "art pieces" you can keep about the house so I thought it might look cute to 'montage' them. Initially I was planning to do my hand too but there wasn't enough clay in the batch :(

So this is what we did:

Recipe 1

The first recipe I tried came from MamaPapaBubba blog (full post here). This was the first time I'd ever heard of baking soda clay - I'd been about to use salt dough - but thought this looked great so why not try it.
So I carefully followed the recipe:
1.25 cups baking soda
0.75 cups cornstarch
0.75 cups water
Heated gently and removed from the heat when it looked like mashed potato and then left to cool for 15 minutes under a wet cloth. And initially it all looked great.
Initially it all looked very promising

But then when it was drying you could see cracks starting to form even in the first 12 hours :( if you read the comments under her blog post it seems quite a common problem.

The cracks are starting to show...

But I was not deterred - time for a new recipe :)

Recipe 2

The above got me thinking. Could you substitute the baking soda for baking powder? (I had a lot of baking powder in the cupboard and no more bicarbonate of soda!). Baking powder is effectively baking soda plus corn flour so I thought by re-jigging the proportions a bit it might just work?

Well it didn't. When the mixture started bubbling and emitting a thick gas as soon as I added the water I began to have my suspicions.... Anyway I persevered, tried my best, added some extra water but ended up just making a nice bubbly white oobleck.

Hubbly bubbly

Now D loved the last rainbow oobleck we made so there was no point in wasting it... He had fun anyway :)

Squish, squish
Recipe 3

Still not deterred I found another recipe with slightly different ratios on The Imagination Tree blog (full post here). This one had a bit more water in which I thought boded well.

1 cup baking soda
0.5 cups cornstarch
0.75 cups water

So I mixed them all together and heated over a medium-low heat. I stirred constantly and removed the saucepan from the heat as soon as the big clumping was starting to form (so about 10-15 seconds) earlier than when I tried "Recipe 1". I left to cool again and the resultant clay was a lot more squidgy/less firm so I was worried it might not dry properly. But I shouldn't have been.

We flattened it into a circle again. D did his handprint and then Iz did hers. By this time they were pros so got it perfect on their first attempt :)

Doof's handprint

Iz's handprint on top

Then I lifted it off the baking paper and put it on a drying rack. I thought this would be better than having to turn it every few hours, as I was worried if I turned it the handprints would get squashed out of shape because the clay was so soft.

And after a few days it was as hard as a rock :) the prints actually even improved with time - the palm lines got more visible - amazing! The clay also adopts a sparkly glistening colour. 

Recipe 3 versus Recipe 1 - I know which I think looks better!!

Then my final decision was how to finish it off. I had originally planned to paint the prints but it looked so beautiful when up against the light...

So pretty...

But anyway here is the final result - I love it!

Perfect keepsake :)

The last thing I need to do is coat it with a layer or two of clear protectant (which was also great in this project) and thread some ribbon through the holes so it's ready to hang. I love that we'll always have a record of just how tiny Iz' hands were as you quickly forget :)


So what are my top tips if you want to try this at home?

   -  Use recipe 3
   -  Take off the heat earlier than you think (you can always put it back on if you want)
   -  Aim for a slightly 'wet' dough 
   -  Use baking paper on both sides of the clay 
   -  Don't press too hard when making the prints as it can make the clay quite thin (although it does look pretty cool in the light!)
   -  Air dry at room temperature rather than put in the oven 
   -  Dry on a mesh rack
   -  Leave as long as possible before painting
   -  I used tempera paints as I've temporally misplaced our acrylic ones, but I think those would've given a more even coverage


And for anyone wondering about amounts as we don't really use "cups" in the UK. I used a full pot of baking soda (200g) and then just scaled everything else around that. We were left with a piece of clay perfect for making the 2 little handprints but had none left over. So if you want to make more than one I'd scale up your ingredients at the start?


Have you ever tried making baking soda clay? Do you have another recipe? I'd love to hear it :)


  1. I know this is an older post, but yay recipe 3 worked for me. It was my fourth iteration of the handprint cast project (and making for grandparents so 10 copies each time), tried another baking soda clay, air dry clay and salt dough, but this one worked with no cracks and a decent impression. Used my dehydrator and they worked out perfectly, thank you!

    1. So pleased it worked for you!! 3 years later ours is still going strong! Hope the grandparents like their presents :)