Nizzy's Bath Bomb Tutorial 

& How to Make the Mould!

Hammer Compression Method (Whack!)

This Bath Bomb Mould designed and constructed by Terry Nisbet  - January 2000

These are  my own observations so please donít assume itís the only method. It worked for me and if it helps you then use it. Its simple and effective and the cost of the parts is very economical. BesidesÖ.everyone else makes round ĎBath Bombsí Why not name these ĎBath Tabletsí ?

Use your own bath bomb recipes, it works equally well

Bi-Carb Soda    300 grams (sieved)

Citric Acid        100 grams  (sieved)

Almond Oil        Enough oil to make the mixture hold together when compressed. I start with a teaspoon then add it in smaller amounts as I go.

I vary this as    I mix it thoroughly with a spoon or a hand cake beater, it should still look dry after adding the oil and if it holds its shape after pressing it into the spoon, I use it then and there, if not I add more oil. You can use any other emollient oil like Coconut Oil, Avocado Oil, Apricot Kernel Oil.

Use liquid cake decorating colours just a few drops at a time until you get the shade you want. If you have powdered colour pigments its even better as you are not introducing water to the mix.


Have the tube mould on a small piece of wood or a bread board.

Spoon in some of the mixture.

Place the plug on the top and pack it down, place more mixture in and press down again.

Put the plug on the top and give a few whacks with the hammer, this compacts it, if its still not enough add some more and tap with the hammer again. Donít worry if the plug disappears below the lip of the tube, you can simply lift the whole thing up and turn it over in your hand and the plug will fall out. Donít be afraid to hit it hard, you want good compaction.

When your satisfied you have enough in the tube lift it up turn it upside down, so the wooden plug is on the bottom of the tube and use the wooden plug as a plunger now and it will slide the bomb up to the top. Another method is to have something smaller in diameter than the plastic tube on the workbench and place the tube over it and slowly push down, the wooden plug will push the bath bomb up the tube.

Lift it off gently and place on a tray to dry overnight.

You can even do multi coloured layers or blend two different fragranceís together.

If doing multi layers use a fork to rough up the previous compacted surface then spoon the next layer on the top and whack it!


The pounding of the hammer compresses it to  bind it together. I have seen recipes using water but I feel this only adds to the problems, the only water I have in mine is the water contained in the food colouring. It will react with the mixture and start to swell, this can show signs of cracking or little bumps forming on the outside. Try dry colours?

I admit my method is a little brutal but the results speak for themselves, they are compressed and dry evenly, maintain the scent and even if the shape is a little boring, you can tart it up with the wrapping. One idea I had was to make several colours and fragrances, wrapped separately in cellophane, then 6-8 of them placed end to end  and wrapped as a single length. 

I mix the bi-carb soda and the citric acid together and sift a couple of times. Put into a bowl then just take enough for the amount of bombs I want. I usually mix enough for 6 at a time.

01 Tools 1.jpg (20376 bytes) 02 Hole Cutter 2.JPG (17161 bytes) 03 Mix.jpg (15124 bytes) 04 Mix 2.jpg (17220 bytes)


05 Compression 1.jpg (17428 bytes) 06 Compression.jpg (13063 bytes) 07 Removing.jpg (8496 bytes) 08 Removing 1.jpg (8416 bytes)


09 Finished 1.jpg (16906 bytes) 10 Finished 2.jpg (15919 bytes) 11 Packaged.JPG (13526 bytes)