It has taken me quite some time to figure out and be able to recreate a rimmed soap design - both in cold process and a combination of melt and pour and cold process. Now that I feel confident in being able to recreate this in a variety of designs with consistent results, I will share how I put this together. For cold process soap, it takes two days to complete. Day 1 to create the rim and allow it to set to be firm enough yet still flexible to manipulate. Day 2 to create the inner core soap. Depending on your formulation, you may be able to do this in a shorter amount of time, but I find the 2 day process works for me. Melt and pour/cold process can be done in 1 day as it takes only an hour or so for the melt and pour rim to set up.
Please note that are at least two ways to create rimmed soaps. The way shown here and to make a thick slab of soap and then shear off a thin layer to use to formulate the rim. You need a custom wire soap cutter to shear the slab into the thin slices. This is a great method for high volume production but does not allow as much creativity in surface design (like the flowers.)
This is an advanced technique so it is assumed that you have formulations that you are comfortable with based on the design you may want to use (slow moving for example.) It is also assumed that one knows how to calculate amount of soap needed for the end result and the size of your molds which will be unique to each individual. Since these are soaps that I do sell, I do not provide the formula I used. If you want to do a complex design, use a slow moving formula.
Things to keep in mind - hints for my success:
- I do not add fragrance to the outer rim - I keep it as simple as possible to avoid issues that fragrances can bring to the soap. You are working with a thin layer so control is important.
- The rim soap needs to gel completely. If not, it will crack when you try to manipulate it.
- I use a variety of formulations but they mostly are 45% hard oils/butters and 55% soft oils.
- I have removed the slab and cut and rolled anywhere from 12 - 24 hours after pouring. The soap is not warm but room temperature. No heat is used to roll and place the rim into the PVC.
- Rim thickness. I find that 4 - 5mm is a good thickness - not too thin that it will crack, not to thick that the outside will stretch too much as you roll it (and create small stretch cracks). This is personal choice, your results and issues may vary.
- I use the same or almost the same formulation for the rim and the inner core soap.
- I soap these at approximately 110 degrees F.
- I use 3" PVC pipe cut to 6 1/2" to 7" lengths. This size works for me because I have short fingers and need to be able to reach into the pipe to manipulate the rim to align the seams for a tight fit.
- Measurements are important if you do not want to waste soap (and who wants to waste good soap.) Decide on the height of your mold first, then determine the size slab you need to make and find or make a mold to accommodate your size so that you do not have to do too much trimming to fit the mold. I use a wooden breakaway slab mold that is just over 14" by 10" lined with freezer paper. For this size mold to get 4 to 5mm thick slab I use 15 ounces oils and allows me to fit 2 PVC molds.
Slab mold lined with freezer paper
1. Mix up your rimmed soap batter and separate out into your colors of choice. For this design I am using pink, dark pink (almost red) and green micas along with my ivory uncolored base. I am also going to accent with some gold mica mixed with oil for the final surface design. I am scenting the inner core soap with a combination of 2 of my absolute favorite fragrances that I know do not discolor or accelerate trace and hold well in cold process soap. Champagne and Crisp Apple Rose - both from Brambleberry. The colors were chosen to match the fragrance combination
2. Pour this soap into the mold in the manner you prefer to create your outer rim design. You may have to lift the mold and maneuver it by tipping it slightly in various directions so that the thin layer of soap spreads evenly to all areas of the mold.
Just poured soap
After manipulating the soap with a thin dowel rod to create the waves of color. The gold mica was added after the swirls were completed.
3. Allow this soap to gel. To insure a full gel on this layer I use the oven set to 170 degrees F. If doing this, make sure your mold is oven safe. Set the oven to 170, then once you place the soap (I cover the mold too) into the oven, turn it off and let it sit for a day to gel and then cool slowly. If your soap is not gelling by turning off the oven, keep it on for 5 - 10 minutes or so. Do not cook the soap as it will wrinkle on the surface. The time and temp can vary and you will need to figure out what works best for you based on the size of your slab, the thickness and your oven. You can also try to use a heating pad under your mold to force gel.
The fully gelled slab
4. Carefully remove the slab from the mold and peel away the freezer paper. This is where the breakaway slab is really handy as it makes it very easy to remove the soap from the mold as you take the mold apart by removing the sides - the slab just slides off the bottom base. This is the slab mold that I use: Collapsable Slab Mold
5. Trim the slab to fit your PVC pipe mold. These measurements will be based on the height, inner diameter of the mold and the thickness of your slab. I trim mine to 6.5" or 7" x 9 3/8". Too short and the seam will not meet, too large and it will overlap too much. The thicker the slab, the shorter the width you will need. You want the ends to overlap slightly so that when you press the soap into the molds to align the seam, it is a tight fit. My slab size allows me to form two rims that fit my PVC molds.
8. Carefully slide the rim into your mold with the seems overlapped. This is where you will then need to manipulate the rim for a tight fit and press the edges so that you end up with a tight fitting seem. This takes two hands so I cannot get a picture of the inside manipulation. If you cannot align the edges due to too large an overlap, you may have to remove it and trim a bit more off the edge - be careful as trimming too much will leave a gap in your rim. I do not line the molds as the rim as already formed and will not stick to the sides of the pipe. Adding a liner, will also create an indent in the soap that will look like another seam.
Slab rolled and placed into the mold and pressed from the inside to the sides to align the edges and create a tight seam.
9. Cap the end of the PVC pipe molds and create your inner core soap. For two 6.5" to 7" tall molds and a 4 - 5mm thick rim, I use 34 ounces oils for the inner soap. You can color this soap and fragrance however you like. I find a solid core and a designed rim coordinate nicely and allow the rim design to pop. You could also do the reverse and create a solid color rim and an "In the Pot Swirl" for the inner soap. Lots of possibilities.
12. Allow to set 24 - 48 hours. The longer you keep it in the mold the easier it is to get out. It can be tricky to unmold soap in a PVC pipe though. I tend to place it in the freezer for an hour or so as it helps remove the soap from the pipe.
13. Cut your soap to your preferred size.
Using melt and pour for the rim. The process is the same but you do not need to wait for the soap to gel, just to set up. I used clear SFIC base. Once set, the thin layer is quite pliable and easy to form into the mold. Below are two soaps using melt and pour as the rim and cold process for the inner soap. Because cold process can and will shrink as the water evaporates out, I did a large water discount (1:1.5 lye to water ratio) to create the cold process to reduce shrinking. Not sure how these will hold up after a full 6 week or longer cure but we shall see.
Dark blue has iridescent glitter to add some sparkle and scented with Sparkling Snowflake from Wholesale Supplies Plus. The teal blue has poppy seeds to add interest in the rim and is scented with Shave and a Haircut from Brambleberry. Even though these soaps have a glycerin melt and pour rim, I was still able to slice them with my wire soap cutter (typically you cannot slice melt and pour with a wire cutter)
Collection of finished rimmed soaps. The melt and pour are on the bottom right.
Alaiyna B. Bath and Body