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How to figure how much oil for mold.

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Zany_in_CO

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cwayneu

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hey paul, thanks for the helpful thread!!..


just curious, where does the .40 come from??
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.
 

Zany_in_CO

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Saranac

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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?
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.
 

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.

??? Do you mean this one:
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:
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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Saipan

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Metric? What the hell is that?

Just remember we put men on the moon with good ol Imperial measurements.
 

LBussy

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Metric? What the hell is that?

Just remember we put men on the moon with good ol Imperial measurements.
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.
 

Zany_in_CO

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Just remember we put men on the moon with good ol Imperial measurements.
You're joking, right? Um, in architecture & engineering, we use mostly metric -- just like soapers prefer to use grams for lotions & potions. I s'pose NASA did too. The interesting thing back then is, when JFK was elected President of the USA, he promised we would land on the moon in 10 years. He also promised that, in those same in 10 years, we would be on the metric system! Maybe that's why he was assassinated?! (Just kidding.)

Americans are resistant to change, even if it's good for us. I'm embarrassed that we are the only "civilized" country in the world that still uses the Imperial system. Sad really and, dare I say, ignorant... in a nice way of course. :)
 

The Efficacious Gentleman

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Not always, mostly not anymore. Miles still, not km. Cm or mm mostly, but a lot of people still think in inches. Height, for example. Weight for people is stone. Cooking is mostly grams It's an odd mix, that is for sure.

Actually, zany, NASA did use a lot of Imperial at that time. Even the lunar module coming down was measuring the distance to landing in feet
 

Saponista

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Yes I am weird, I only know my height in ft and ins, and distance in miles but I measure everything else in metric. I weight myself in stone and lbs, but I weigh everything else in metric. We do a weird sort of hybrid lol
 

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Mile is difficult for me even I know it is 1600 m, inch is weird it has a tiny bit less that 2.5 cm, I am metric and took me a long time to get ounces :) Thanks heaven we use Km and litres in Canada, there is always also imperial measurement on most things but will be on the second place ie 1000 g /2.2 lb
 

Saipan

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I was joking, yes, but I do like to point that fact out. The UK uses Imperial for a good many things still, I do blacksmithing, and often things are still Imperial for that in the UK.
 

iwannasoap

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I tried this with the recipe I just made yesterday. I figured .40 stood for 40% of oils. I was definitely wrong about that one but I compared it to what I did yesterday because I only lost 2.46% (and I was scraping the bowl) so It was pretty close to use it as an example.
Anyway, doing this for the same mold I used yesterday works better for me if I used .42 instead of .40. If I would have done this yesterday I would have lost less then 2.46% because that would have put me a little more then a 1/4 oz closer to my target.
To make it short, .42 works much better and is closer to the top of the mold in my opinion. I'm like the other guy here, "What is .40?"
 

The Efficacious Gentleman

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Maybe in some instances .38 is better, too, so they had to find an average which is near enough all of the time, but unlikely to be perfect every time.

At least thanks to whoever worked it out first time round, you had a ball park figure to start with, even if they didn't make it totally perfect for your particular batch of soap
 
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