Honeycomb Soap

This instructable shows how to make a honeycomb-shaped soap. I also show how I milled my own mold for the soap.

I referenced the Bramble Berry website for this specific recipe, but I edited the fragrance and specifics to what worked for me!

• Machinable foam
• Mold Star 30
• Ease Release 200
• Borage Oil (10%) (3.3 oz)
• Olive Oil (45%) (14.9 oz)
• Cocoa Butter (7%) (2.3 oz)
• Coconut Oil 25%) (8.5 oz)
• Shea Butter (6%) (2 oz)
• Beeswax (7%) (2.3 oz)
• Lye (4.5 oz)
• Distilled Water (10 oz)
• Honeysuckle fragrance oil (2 oz)

I decided to make my mold in Fusion360. My goal was to create a simple soap mold for my mom. It was supposed to resemble a beehive.

I began by creating the mold positive/shape of my soap. Then, I designed a frame around the mold positive.

I uploaded my Fusion file for reference. It also has toolpaths which I will explain in the next step.

Once I had developed my model, I created my toolpaths for my rough and finish cut using the Fusion CAM workspace (which was recently renamed the manufacture workspace).

In the manufacture workspace, I created a new setup and adjusted the stock dimensions to my foam. I had measured my foam piece to be 7 inches x 7 inches x 0.994 inches. I created my model to the correct height and width, but I needed to adjust my height. To get my height to the correct 0.994 inch dimension, I added a top offset of 0.494.

After I dimensioned my stock, I edited the setup origin. I decided to place my origin at the bottom-back-left corner so the xy axis lines would correlate with the ShopBot.

The first toolpath that I created was my facing toolpath. I selected the facing option from the 2D toolpath menu. Then, I created a flat-end mill bit with these feeds and speeds.

Here are a few resources that I found to help with finding speed and feeds for machinable foam. Your feeds and speed really depend on your material and bit specificities.

• https://support.bantamtools.com/hc/en-us/articles/115001671814-Machinable-Foam
• https://forums.autodesk.com/t5/fusion-360-computer-aided/best-modeling-foam-cut-feed-speed-setting/td-p/6406126
• https://www.rcgroups.com/forums/showthread.php?1822478-At-what-speeds-to-CNC-mill-foam

Once I had set my feed and speeds for my 0.25 inch bit, I worked on dimensioning the bit itself. I included a photo of my dimensions for a 0.25 inch bit. (Certain lengths in the visual can depend on the bit installation process.)

Once I had created the first facing toolpath, I moved on to my rough cut which would remove a majority of the foam material from my pocket. To do this, I used the 2D adaptive clearing toolpath and the same bit that I created for my facing toolpath. This first toolpath would remove the majority of the material surrounding the mold but would not touch the inner ridges.

Next, I tried to create a 3D adaptive clearing toolpath for the inner ridges of my mold, but my bit was running into the sides.

To solve this, I created a stock contour around my hexagonal blob chain. This only allowed the bit to clear out the areas in the outline.

To clean up my rough cut, I created a finish cut that had a significantly smaller stepover (0.125)

Here is a video of my toolpaths simulated.

Finally, I exported my toolpaths as a ShopBot file. I did this with the post-process tool.

While still in Fusion, I figured out the required volume of molding material using the boundary fill tool. (I watched a video to learn how to do this.) I found I needed about 334 mL of the molding material. This would mean that I would need 167 mL of part A and 167 mL of part B.

To create my mold, I milled my design out of machinable foam on the ShopBot.

I started by cutting a 7 inch by 7-inch piece of foam using the bandsaw. To adhere my foam to the CNC bed, I used double-sided tape.

To reach my desired result, I milled my design two times. My first attempt milled all the way to the base of the ShopBot. I stopped the file because I was afraid the middle piece would fly out since I had only secured the four corners. After looking at my Fusion toolpaths, I found my first 2D adaptive toolpath was cutting all the way down into the bottom of my mold. I didn’t notice this because my stock was hiding my toolpaths. I am a little confused why the simulation didn’t display the problem. I theorize that the toolpath may have left a thin sheet of material that would cover the bottom of the simulation, but in real life, the inconsistencies in the foam thickness would create the thin, patchy film seen in the following picture.

To fix my toolpath, I switched to a 3D pocket which I confined to the inside of the mold. For this toolpath, I could easily see the toolpaths!

Here is a video of my milling process.

Once I had my foam design ready to go, I was able to pour my mold! I used Smooth-on Mold Star 30 to pour my mold. I also used Ease Release 200.

After reading over the Moldstar 30 information, I learned the liquid would take 6 hours to cure. I also found the ratio of A:B was 1:1.

To make clean-up easier, I laid out a piece of cardboard on my workspace.

Then, I sprayed the release agent onto my mold. Since I opened new molding material, I stirred the parts separately before combining them.

To find out how much of part A and part B to pour into my cups, I filled a measuring cup up with 334 mL of water and then distributed it equally into my mixing cups. After, I poured the molding materials into the same height on the cup. Finally, I stirred the two parts together slowly and in a figure 8 pattern.

I poured my mixture into my mold with a thin stream to prevent air bubbles.

Once I had gathered all my materials, I had to measure them out on a scale and melt them down together. I melted the borage oil, olive oil, cocoa butter, coconut oil, shea butter, and beeswax in short increments in the microwave. I recommend starting with 30-second increments and then taking it down to 15-second increments. I mixed the oils together with an immersion blender.

I kept the lye and water in a separate bowl. CAUTION: Lye is extremely corrosive and should not make direct contact with your skin. Here is a safety datasheet for lye. You can adjust the amount of each ingredient depending on how much soap you want to make, but you have to adjust the lye as well.

I mixed the oils and lye together with my immersion blender after they had reached the same temperature. I added the lye mixture to the oil container and made sure to have my proper safety gear on throughout the whole process. Finally, I got to add my scent. I scented my soap with this honeysuckle fragrance.

Finally, I poured the mixture into my mold and let it set for 48 hours. Once it was set, I could remove it from the mold. Here is what my final soap looked like!