I have a heart 6 cavity mold, the soap site said they should hold about 3 oz. ea. equaling 18 oz...2.5 x 2.5 x 1.25 x .40= 18.75...that being stated....
I make a recipe of 18oz. on the SoapCal, figuring that they didn't need to be to the perfect top...but as I poured the 6 to the rim, I scrambled to find something else for the overflow, had a log mold lined so put it in that and I had 10oz, extra(weighed after it set up)....I can use it for myself but don't really want it left over...I need to make 12 more batches for a wedding, don't really want to waste or be short...am I doing something wrong..well I must be...Can you help? Thanks SO much!!! Answer:
I'm guessing that the manufacturer of the mold is referring to the finished weight of the soap and not the weight of the oils in the soap.
The mold volume formula gives you the weight of the oils needed for a recipe that will fit in your mold.
The measurements you are using indicate that the molds are square when in fact a heart is definitely not square.
You will not be able to use any of the mold volume formulas on my site to figure out the amount of oil needed in your recipe since the mold is an irregular shape.
My suggestion is to take a look at the amount of overflow you had. Take a guess as to about how many heart shaped bars it would equal.
Add that number to the six you poured. Now divide the amount of oil you used by that number. This will give you an approximation of how much oil will be needed per soap cavity. Times that number by 6. That is about how much oil you will need for a recipe that will make 6 hearts.
Lets say that the overflow looks to be about equal to 4 heart shaped bars. 4 + 6 = 10.
18 ounces of oil divided by 10 equals 1.8 ounces needed per cavity.
1.8 ounces of oil times 6 cavities equals 10.8 ounces of oil needed for the recipe.
Hope that makes sense,