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. Oct 15, 2017 #201

    SoapAddict415

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    I realize this thread was started in 2008 but I'm hoping that someone can answer my question. I've seen this formula but with different numbers such as .40, .38 & the last post suggested .37. I don't care which number I use, I can't seem to get the right amount. When I've tried for example 7 * 3.75 * 3.5 * .40= 36.75 ounces (rounded up to 37) as the amount of oils, I end up with a few ounces of too much soap. So, reasoning that the formula calculates volume/how much the mold holds, I've tried creating recipes that have a total weight of 37 oz but I usually end up a few ounces shy of a full mold. Where am I going wrong?
     
  2. Oct 15, 2017 #202

    dibbles

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    Are you using a water discount? Using that formula, with full water, 31 ounces will fill my mold. At 30% lye concentration, 32 ounces will fill it, with maybe a bitty bit left over.
     
  3. Oct 15, 2017 #203

    SoapAddict415

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    I usually use full water, 38% and whatever lye concentration that soapcalc gives me. I made this mold & 1 other about 2 years ago & I don't think I've ever been able to correctly calculate how much soap batter I need.
     
  4. Oct 15, 2017 #204

    soaperwoman

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    I know this may sound dumb but I hate math so all I do is fill my mold with water and then measure that to get my volume. Then I reverse engineer the water amount on a soap calc and oila! It isn't very scientific but it works every time.
     
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  5. Oct 15, 2017 #205

    SoapAddict415

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    I've done that with my silicone molds but this is a homemade wooden mold. It's not going to hold water.
     
  6. Oct 15, 2017 #206

    dibbles

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    Why don't you purposely make a little too much batter with your regular recipe/water amount and weigh what is left when your mold is full?
     
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  7. Oct 15, 2017 #207

    Millie

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    If you are having good luck using that method, could you line your mold with a garbage bag for your water measurement?
     
  8. Oct 15, 2017 #208

    SoapAddict415

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    I hadn't thought of that. Thank you, it's worth a try.
     
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  9. Oct 16, 2017 #209

    Zany_in_CO

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  10. Oct 16, 2017 #210

    SoapAddict415

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  11. Oct 16, 2017 #211

    Zany_in_CO

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    I just checked it. It looks like you have to go to the calculator first in order to get to the "resizer" on the next page, where you can then type in the measurements of your mold and it gives you the amount of oil needed for that mold.

    http://summerbeemeadow.com/sites/all/sbm_calc_input/calc_input_page_1.1.html

    HTH
     
  12. Oct 17, 2017 #212

    SoapAddict415

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    Thanks. I was trying to figure it out but I didn't get far. I'll try again after work tonight.
     
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  13. Oct 18, 2017 #213

    cwayneu

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    The .4 is actually an approximate conversion factor of any volume in cubic inches, to ounces of oils for that volume of soap. The total ounces will be the oils plus the lye and water, but Soapcalc will tell you this exactly, depending on things like superfatting and lye/water ratio. Some chemist probably figured this out way back when.
     
  14. Oct 18, 2017 #214

    SaltedFig

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    Sorry, but in metric that linked calculator has major flaws.

     
    Last edited: Oct 18, 2017
  15. Oct 18, 2017 #215

    Zany_in_CO

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    ??? Do you mean this one:

     
  16. Oct 18, 2017 #216

    Saranac

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    There are too many variables to successfully use another person's (or calculator's) conversion factor (especially if you don't want too little or too much); you need to calculate your own. This is how I handle this type of situation:

    My current recipe yields bars that are 2.5 inches tall. Now assume that I want to increase their height to 3 inches. My conversion factor is:

    New Height / Old Height

    For my example above:

    3 / 2.5 = 1.2

    I would then scale my formula up by multiplying the weight of EVERYTHING in my formula by that number.

    This also works if you want to make smaller bars. Lets say I want to scale my formula down, so that my 2.5 inch tall bars are only 1.5 inch:

    1.5 / 2.5 = 0.6

    I could then scale my formula down by multiplying the weight of EVERYTHING in my formula by that number.
     
  17. Oct 18, 2017 #217

    SaltedFig

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    Yes (sorry, I thought that clinking the link in my post would take you directly to your post ... it worked when I tried it. Thanks for letting me know it's not helpful!).

    Test by using grams, enter 1000grams of olive oil at 10% superfat, and resize to a soap bar measuring 2cm high by 5cm long by 3cm wide. See how many grams of oil it says you need.

     
  18. Oct 25, 2017 #218

    SaltedFig

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    Measuring mold volume without maths

    Using salt to get the volume of your mold (and avoid all volume maths!):

    Pour salt into your desired mold, then pour the salt from the mold into a measuring jug. Read volume.


    To use the multiplier from this thread (thank you!) to work out the weight of oil needed for your recipe.

    For metric, multiply your volume by 0.7
    For imperial, multiply your volume by 0.4

    You will need to fine-tune this multiplier to suit your own recipe (as it varies with different lye strengths, additives, oils etc.)
    (so in Steve's example below, his multiplier is accurate at 0.37)


    To resize your recipe to fit a new mold:

    Pour salt into your existing mold, then measure the volume of the salt. Note the volume.
    Pour salt into your new mold, then measure the volume of the salt from the new mold. Note the new mold volume.

    Divide your new mold volume by your old mold volume. This is your Resizer Value.

    Multiply your Resizer Value by the total oil weight of your original recipe.

    The answer given is the total weight of oil you need for your new mold.

    In one calculation this becomes New Volume / Old Volume * Original Weight = New Weight

    1/ The Resizer Value will work just as well to calculate recipe weight (by multiplying the Resizer Value by your recipe weight, instead of oil weight)

    2/ The Resizer Value will work using any weight measurement (eg. grams, kilos, pounds, ounces ...)

    3/ You can substitute any pourable solid for the salt. So you can use salt, rice, split peas, sand ... whatever, so long as you can pour it.


    Steve's example:
     
    Last edited: Oct 25, 2017
  19. Nov 1, 2017 #219

    Saipan

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    Metric? What the hell is that?

    Just remember we put men on the moon with good ol Imperial measurements.
     
  20. Nov 1, 2017 #220

    LBussy

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    Didn't we also screw up some mission or other trying to convert between the two?

    I sure like math using metric measurements better, but I still don't know what to expect out of C ... like, what's comfortable? I know 70F is fine but remembering 21C is comfortable eludes me most times.
     

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