Edit:  07 NOV 2024 - Added letter bases, so you can imprint a letter in the bath bomb now.

My son wanted to make some bath bombs for his mom for Christmas after watching a video online, so I made this mold to knock out a bunch of them without having to purchase or print a bunch of molds. The instructions we used are here and they recommend putting the finished mix in the molds and letting them dry before removing them. Well, who wants to wait when you can compress them into a nice circular puck that can be removed immediately (if you are very careful).

You only need to print one bottom. You can print a blank bottom, or the heart bottom, but you do not need to print both. I made the parts very loose so the gritty mix wouldn't cause anything to bind.

I bought the citric acid, corn starch and essential oils (lavender and lemon were the two I bought) from Amazon. The epsom salts I picked up at my local grocery store when I stopped by, and the baking soda from Costco on one of my usual trips there.

The bath bombs in the picture are lavender and have lavender buds added into the mix in addition to the essential oil. I picked up the lavender buds from Amazon as well.

Anyway, on to the parts of the mold. I printed them with 3 walls, 4 top and bottom layers and 20% infill so that I could exert a lot of force on it and not worry about it being deformed. I am a big dude - 310lb - 136kg - 21.4 stone - so we put the mold bottom in the mold ring, loaded it up with ~1/2 cup - ~120cc - and put the mold center in and I stepped on it.

We then pushed the center down and it ejected the bottom and bath bomb into our hand and then carefully removed the bath bomb from the bottom. We gave it a quick wipe and did it again until we were out of mix.

EDIT: Just wanted to add that due to the design of the mold, you can put quite a varying amount of mix in it and it will still work just fine. What will happen is the band around the middle will get thicker as you increase the amount of mix you put in. So, if you are shooting for a specific weight, you can do that and not worry about whether the mold will compress it properly or not.

Print Settings

Printer Brand:

Prusa

Printer:

i3 MK2S

Rafts:

No

Supports:

No

Resolution:

0.2mm

Infill:

20% Cubic

Notes:

PLA rn4 layers top and bottomrn3 wall layers

Category: Bathroom