How to figure how much oil for mold.

Discussion in 'Lye-Based Soap Forum' started by Soapmaker Man, Mar 26, 2008.

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  1. Jul 13, 2014 #161

    kmarvel

    kmarvel

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    I made a 12 x 12 2 1/2" wooden mold. I come up with 144 oz of oil for this 5 lb mold. Does this sound even close???
     
  2. Jul 13, 2014 #162

    Hazel

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    I came up with the same total of 144 oz. But that sure does sound like a lot. That's 9 lbs of oil and you say it's a 5 lb mold. I have a 5 lb mold (according to the manufacturer) which is approx. 3.5 x 2.5 x 18 and I had calculated 63 oz of oil for it. Of course, I always use more because I like to have extra for some individual cavity molds. Hopefully, someone who is better at figuring out how much oil per mold will be able to give a definite answer.
     
  3. Jul 13, 2014 #163

    kmarvel

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    Hazel, I had another 5 lb recipe that used about 68 oz. That sounds like more in the ballpark to me.
    But that formula 12 x 12 x 2.5 x .4 didn't work for me.

    And I am like you, I will use 70 oz of oil and any left over go into yogurt cups for sample soaps or guest soap. :)
    We think alike. haha

    Kathie
     
  4. Jul 13, 2014 #164

    wetshavingproducts

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    That cannot possibly be a 5lb mold. You have 1 entire square foot of area and then 2.5" of depth.

    That's a volume of 360 cubic inches.

    Compare to Hazel's volume of: 157.5 cubic inches.
     
  5. Jul 13, 2014 #165

    kmarvel

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    Yup, and the 111.3 oz of soap barely fit in the bottom of the mold. oops.
    I told you I was challenged in math. hahaha If anyone could give me the total oz this mold holds, I would be obliged.

    PS, I got these mold dimensions off of a youtube "how to make a soap mold" video.
     
  6. Jul 13, 2014 #166

    Sprag

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    I came up with 144 oz according to your measurements. You have a 9 lb mold.
     
  7. Jul 13, 2014 #167

    Sprag

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    144 oz's divided by 16 = 9lbs
     
  8. Jul 13, 2014 #168

    Hazel

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    The excess does make nice guest soaps. Candy molds work great for tiny decorative soap.

    Are you going to try another batch with 144 oz of oil?
     
  9. Jul 13, 2014 #169

    kmarvel

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    I went to Summer Bee calc and put the 12 x 12 x 2.2" in for the oils and came up with 132 oz of oil and total soap before CP cure with 193.5 oz of soap. Which with the 132 oz of oil comes to an 8 lb mold. DANG!!!!!! I made a honkin' soap mold!!! hahaha

    Live and learn!!! I quickly (fastest ever) lined a 3 lb mold and repoured my soap in that along with 4 yogurt cups. haha I think it will be ok.
     
  10. Jul 13, 2014 #170

    kmarvel

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    Decided to make them 2.2" high instead of 2.5". :)
     
  11. Jul 14, 2014 #171

    Hazel

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    At least you made your own soap mold. I wish I could make my own. Please post pics of this batch and let us know how it turned out.
     
  12. Jul 14, 2014 #172

    kmarvel

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    Hazel, I will do that! This weekend it is back to making a "smaller" soap mold. 144 oz of oils sound like a lot to me!!
     
  13. Jul 27, 2014 #173

    LBussy

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    Hey all ... sorry for bumping this thread but I thought I would share:

    [Link no longer functional. Removed by SMF Modmin Team]

    This is a spreadsheet that will allow you to figure mold volume in ounces or grams, in rectangular or round molds, with 0.40 or 0.38 factors. For round use the green boxes (H & D), for rectangular fill in L, W and H. If you have any number (including 0) in the D (Diameter) box it will figure the volume of a round container based on that and the height, so be sure to delete that field if you intend to figure rectangular.

    I'll try to remember to leave this up and available, but it's on my working DropBox account and could be deleted or moved so snag it now if you want it.
     
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  14. Jul 27, 2014 #174

    Hazel

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    Lee -

    Thanks for sharing! I downloaded it to DB and played with it. My results were just one ounce off (small mold) to 3 ounces off for the 5 lb mold. It could be because I didn't double check the width or it could be because I discount water and have room for more oils. Anyway, it's very helpful and it's generous of you to share the calculator. :thumbup:
     
  15. Jul 27, 2014 #175

    LBussy

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    Happy to help. I can't speak to why these are right, just that *if* the whole 0.40 and 0.38 factors are correct then these are correct. :)
     
  16. Jul 27, 2014 #176

    Bubli

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    Stupid question....I am reading conflicting opinions on how to calculate and what the results mean. After reading a few different sites, as best I could gather, when you multiply L X W X D X .40 you get the amount of oils AND water that mold will hold,right? Or do you have to add your water amount to this total. I am about to order new molds and wanted as perfect a fit as possible, I found some people that make custom. So is it just the oils or water too? The .40 represents water right?
     
  17. Jul 28, 2014 #177

    LBussy

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    Not a stupid question Bubli, was wondering the same thing. I just took a factor that someone else posted and made a spreadsheet. :)
     
  18. Jul 30, 2014 #178

    scotsman

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    I may be wrong here, and this may have already been said in an earlier post, but from looking at the formula and comparing it to various base recipes I have, it would seem that the .40 is actually the water % in the recipe, or rather, an approximate. This would explain why it doesn't come out quite right for some. If you use a water % other than 40 then the formula will be off a little bit. So, if I'm correct, and I may not be as math is not my forte, the formula should be as follows:

    Length x Width x Depth = Volume

    Volume x Water % = Total oil weight for mold

    By way of example lets say the interior dimensions of the mold are:

    Length=24"/Width=3"/Depth=2"
    So...
    24 x 3 x 2 = 144 cubic inches volume

    If we're using a water % of 40 then:
    144 x .40 = 57.6 oz of oils

    But now let's say it's your first time making soap and first time using soapcalc so you opt to go with the default 38% water. Your equation is 144 x .38 = 54.72 oz of oils

    So that 2% variance in water gives us a variance in total oils of 2.88 oz. not that big of a difference, but let's say you use 33% water for your recipe. Now your equation is:
    144 x .33 = 47.52 oz of oils

    That gives you a variance of 10.08 oz of oils. This is a significant difference. If you make your recipe with 33% water, but calculate using the standard .40, then you will still have a considerable amount of room left in your mold after you put the batter in it. And this doesn't even account for coloring, fragrance, or additives...though these are usually a much smaller % in most recipes.

    The initial formula with the standard figure of .40 is solid, and will get darn close for most people, but if your recipe calls for a rather steep water discount then you would benefit from recalculating and swapping out the standard .40 for whatever your water % happens to be. 38% water would be .38, 33% water would be .33, etc.

    Again, this is just a theory and I may be way off base with this one. Maybe at some point if I have some spare time and supplies I will do an actual test of this theory and post my findings here. I'm actually rather curious to know for sure. I hope this is helpful.
     
  19. Jul 30, 2014 #179

    coffeetime

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    Scotsman, if the water amount used is going down from 40% to 33% in your example, wouldn't that mean you need more oils to fill the same volume mold, not less? With less water used, you would want to increase how much batter you are making by the missing water or your mold will be short.

    I usually water discount by varying amounts depending on the recipe, and I found I couldn't use that formula at all. I had to trial and error it with that formula as a starting point. Took a couple of batches but not a big deal.
     
  20. Jul 30, 2014 #180

    scotsman

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    @coffeetime- you're right. I just reread my post. That's what I meant to write. I haven't really slept much the past couple days and got it jumbled around, lol! I guess I should try to go to bed ;)
     

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