JeremyM Posted February 11, 2018 Share Posted February 11, 2018 (edited) I'm a science teacher, and my students are making bath bombs to learn the chemistry involved but also gain some entrepreneurial skills. After doing a lot of research, we decided on this recipe and basic procedure below. For the most part, we used aluminum molds. While half of them turned out pretty good, the other half all have cracks. I've read some forums about the humidity of the room, but it's not at all humid in my classroom. I appreciate any and all feedback! 1 cup baking soda 1/2 cup citric acid 1/2 cup cornstarch 1/2 cup salt (kids chose between epsom salt, dead sea salt, and himalayan pink salt) 1 tbs oil (kids chose between coconut oil, olive oil, grapeseed oil, and vegetable oil) 2 tsp fragrance oil 1/4 tsp powdered colorant ~2 tsp water Basic procedure: 1. Mix all of the dry ingredients together. 2. Combine oil and fragrance oil to dry mixture. 3. Use pipette to slowly add water while mixing until desired "wet sand" consistency is achieved. 4. Make molds, leave in mold for 2 minutes, then take out and let air dry on a paper plate. Edited February 11, 2018 by JeremyM Quote Link to comment Share on other sites More sharing options...
TallTayl Posted February 11, 2018 Share Posted February 11, 2018 Cracking can be caused by many things. Most commonly, mine crack if: - the mixture Is too wet (activating inside as the outside dries). - the wrong wetting liquid (too much water or witch hazel. A 50:50 91% rubbing alcohol and water works well) - if the ingredients are added in the wrong order. Sounds weird, but adding citric last after the rest is to the right wetness in the bowl helps. - if the molders are packed too hard, i.e. the mold filled too much. - uneven drying, drafts where drying use a spray bottle to wet. The finer the most the better. Mine pop out of the molds almost immediately. If they are not over or under filled they are perfect consistency and hold up well. salts can cause problems also as they are hygroscopic. Dead Sea salts are the worst. Quote Link to comment Share on other sites More sharing options...
TallTayl Posted February 11, 2018 Share Posted February 11, 2018 Oh, and Keep the mixture moving and "fluffy". Heres a thread where I posted a video of making mine. Quote Link to comment Share on other sites More sharing options...
JeremyM Posted February 11, 2018 Author Share Posted February 11, 2018 2 hours ago, TallTayl said: Cracking can be caused by many things. Most commonly, mine crack if: - the mixture Is too wet (activating inside as the outside dries). - the wrong wetting liquid (too much water or witch hazel. A 50:50 91% rubbing alcohol and water works well) - if the ingredients are added in the wrong order. Sounds weird, but adding citric last after the rest is to the right wetness in the bowl helps. - if the molders are packed too hard, i.e. the mold filled too much. - uneven drying, drafts where drying use a spray bottle to wet. The finer the most the better. Mine pop out of the molds almost immediately. If they are not over or under filled they are perfect consistency and hold up well. salts can cause problems also as they are hygroscopic. Dead Sea salts are the worst. Thank you so so much TallTayl! I searched through these forums but somehow missed your videos. They were super helpful. I'm pretty sure our problem is that we're packing them too tight. It's my fault because I told them to do it. That's because everywhere I read said we should do that. Ugh. Anyway, I'm also going to have them use rubbing alcohol solution in a spray bottle instead of just water in a pipette, and I also love your idea for using packing materials to prevent the bath bombs from being flat on the bottom. I'm looking forward to testing some more tomorrow! 1 Quote Link to comment Share on other sites More sharing options...
Sarah S Posted February 12, 2018 Share Posted February 12, 2018 Bath bombs are my least favorite thing to make! In addition to the reasons TT listed, mine crack if: - I look at them sideways - forget to switch the music to soft bath bomb lullabies - make them on days that end with "y" - curse them roundly and hurt their little bath bomb feelings So in summary mine crack every time! 😂 @TallTayl, I missed that video too, thank you for posting that! And the tip about adding the citric last was new to me too! @JeremyM, sounds like a very cool experiment to do with the kids! 1 2 Quote Link to comment Share on other sites More sharing options...
katmeltswax Posted February 13, 2018 Share Posted February 13, 2018 19 hours ago, Sarah S said: Bath bombs are my least favorite thing to make! In addition to the reasons TT listed, mine crack if: - I look at them sideways - forget to switch the music to soft bath bomb lullabies - make them on days that end with "y" - curse them roundly and hurt their little bath bomb feelings So in summary mine crack every time! 😂 @TallTayl, I missed that video too, thank you for posting that! And the tip about adding the citric last was new to me too! @JeremyM, sounds like a very cool experiment to do with the kids! I have found with experimenting ,my bombs kept sinking in the tub .I omitted the epsom salt & they actually float on top of the water. I was thinking the salt was weighing them down.My grand daughter loves bath bombs ,along with making them .We have tried several batches , without the salt with good luck .We have had some cracking ,however the humidity in South ,Tx is super high most of the time. I think this makes a great project for your students ,great idea. Quote Link to comment Share on other sites More sharing options...
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