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 30, 2014 #181

    LBussy

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    The formula looks up the value in the header, so once you find out what factor works for you, you can change your personal copy of the spreadsheet and it will work as you intend.
     
  2. Jul 30, 2014 #182

    scotsman

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    I want to try out that spreadsheet but unfortunately can't do it from my phone. My laptop took a header off the table and it destroyed the screen.
     
  3. Aug 1, 2014 #183

    Hazel

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    Well, I'm not a math genius but I didn't think I was this bad at math. I went by the amount I calculated for a 5 lb mold and I still ended up with extra soap. It's not a big deal since I like to have extra to make small soaps in individual molds. But I still don't know why my amount is so off. According to the calculator, the mold 18 x 3.5 x 2.5 = 157.5 x .4 = 63 oz. (I should mention this is a new mold. I usually make 2 lb to 2.5 lb batches. I also don't generally fill the mold all the way to the top so I calculated slightly less which is why my original amount was a few ounces off.) Anyway, I decided to go with the calculated amount based upon the formula of 63 oz + 1 extra oz so I'd have the large loaf and a little extra for one individual soap. Since I used 33% lye concentration, I expected the loaf to be slightly under 2.5" but I was able to fill to the top and ended up 14.7 oz extra soap. Of course, the leftover soap's weight would include water, lye and additives. Still, this is an excessive amount to have left.

    If I calculate using .33, it comes out to 52 oz (rounded off). This actually seems to be a more accurate amount for this size mold. I'm going to try another batch this weekend and use 54 oz to see how full I can get the mold plus possibly have a little left. I'll have to report back after I make it.
     
  4. Aug 1, 2014 #184

    LBussy

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    You can change this number to adjust for the multiplier that works for you and your process.

    [​IMG]

    Again I was taking for granted that these numbers were correct so if the collective finds out that they are not they can easily be edited. I have two spots there so you can say "I know somewhere between X and Y works for me" and show that range.
     
  5. Aug 1, 2014 #185

    Hazel

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    Thank you! I didn't even think of changing it. I decided to double check the size of the mold because I had been using the sizes shown on the site. I thought maybe the mold is slightly smaller than was shown in the description. Nope...measurements were correct.

    I'm learning something new. I'd never worried about calculating according to the formula since the small molds I used I had already learned how many ounces of oil I needed. So, I never double checked them based on this formula.
     
  6. Aug 3, 2014 #186

    scotsman

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    I tried the formula with my small loaf mold that I use for test batches but changed the .40 to .38 because my water is 38% and it filled the mold almost perfectly. I'm going to try another batch using 33% water and use .33 as the multiplier to see if it works. Will post up the results after the test. Keeping my fingers crossed.
     
  7. Aug 5, 2014 #187

    LBussy

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    Okay I did some more work. The "factors" provided were a pretty close rule of thumb but as folks have noticed not always right. I have done a new spreadsheet that should be much closer AND allows one to tailor the water%.

    [​IMG]

    Here's the spreadsheet - as always please download if you want to keep it because it's possible I move something and break the link at some point.

    I don't know how everyone figures water but this assumes water as a % of oil weight as shown on SoapCalc. It also assumes the oil you use weighs 0.033 lb/in^3. "Solid" oils like Lard, Tallow and Shortening weigh 0.031 lb/in^3 but I *think* that's as a solid so using the oil number only should get you very close.

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

    As always, please let me know if you see a glaring mistake.
     
  8. Aug 5, 2014 #188

    scotsman

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    I really want to download and try out this spreadsheet. **** my laptop for committing suicide. I really need to get a new one.
     
  9. Aug 5, 2014 #189

    LBussy

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  10. Aug 5, 2014 #190

    scotsman

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    Thank you for the link. I'll have to wait till I get a new comp though because on my iphone it's read-only :(
     
  11. Aug 6, 2014 #191

    Hazel

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    Thank you, Lee! I'll have to play with this one.

    I did find 54 ounces of oil without a water discount almost filled the 5 lb mold. I was a little disappointed because I wanted some to fill a little dragon mold. I used your new calculator and it came up with 61.77 oz. I'll have to try this amount but it won't be until the weekend.
     
  12. Dec 11, 2014 #192

    Tilia

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    I use metric measurements and everyone seems to agree on something around volume x .7 to calculate the amount of oils needed for a mold. So I tried using that twice now and end up with less soap than needed both times.

    I used a tea-box with 2 compartments today with each compartment measuring 8 x 6.5 x 4.5 cm's. So multiplying those measurements by 2 and then by .692 I ended up with 323 grams of oils needed. While these molds are small I still ended up with the soap being over half a centimeter below the line I wanted it to reach.

    For the recipe I used the standard water amount used in soapcalc of 38%. I that what makes a difference? Not sure on how to factor the water amount in the calculation.
     
  13. Dec 11, 2014 #193

    IrishLass

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    Yep- the water amount (and any other extra additives included) will have an effect on the level. I don't exactly know how to calculate those variables in, though. I just use the equation as a rough guide and then keep meticulous notes of the actual outcomes and adjust from there.


    IrishLass :)
     
  14. Feb 2, 2015 #194

    Cactuslily

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    Idk why I'm still struggling so much! I seem to have a mental block when figuring out what size mold to use for what recipe. For example I made a batch of soap using BB 10" mold. Per calculations, I got 38.5oz. It states on website it holds 50. I'm assuming the recipe given could have had more soap added to mold so that's the differance. If a recipe states it makes a2 lb batch, does that mean I can use my 2.5 mold? Why am I having such a hard time?! I'm feeling my age! Am I overcomplicating this? L x W x H x .40= ounces of oils needed. This doesn't account for water and additives, correct? I plugged in 50ounces to soap calc ( which is what BB states). My recipe came out with a total of 53.1 ounces not including FO. The original recipe held total of 43.8 ounces. Does that mean my recipe won't fit into a 50 mold? Am I even making sense? Uggh! Probably not.
     
  15. Feb 3, 2015 #195

    Saponista

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    LxWxHx0.4 is the calculation you would use if you were using full water. So you would do that and the resulting value is the amount of oils you would put into soapcalc with full water to fill your mould. Any other additives on top of that will increase the volume further and overfill the mould. If you are using a water discount then you need to do a different calculation. If you put the amount of fragrance you want to use into soapcalc too, it will take it into account for you I think.
     
  16. Jul 20, 2017 #196

    TrishNZ

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    Has anyone worked this out in metric?
     
  17. Jul 20, 2017 #197

    Kittish

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    Post #187 has the weight/volume ratios for water, oils, and solid fats given in both metric and imperial. It's kind of clunky to get there, but with that info, plus the measurements of your mold you should be able to come up with a fairly close answer.

    Also, this is an old thread. Last post before ours were over two years ago (though I'll admit the info in the thread may well be handy to several of us new folks). Necro posting is kind of frowned on, overall. Much better to quote snips from the old thread you're referencing in a new thread.
     
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  18. Jul 20, 2017 #198

    TrishNZ

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    Sorry I am new and just using the search feature. I am not sure what Necro posting is.
     
  19. Jul 20, 2017 #199

    Kittish

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  20. Jul 20, 2017 #200

    Steve85569

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    L x W x H = volume

    Trish,

    If you calculate in metric (cm) then multiply volume by 0.70 for the weight of oils that will fit.
    If you calculate in inches use 0.37 for the weight of oils.

    Some corrections will need to happen because of additives but this get me real close.
     
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