More maths, calculating gross weight (mass)

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PerthMobility

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I am confused about how to add up the total of my ingredients in Cold Processing so that I fill a mould but waste as little as possible.

So if I take 1500mls of water and add 650gms of sodium hydroxide do I get 2150 of lye or is some lost through heat?

Then if I then blend 3,700gms of oil and 150gms of essential oil with the lye, do I get a mass of 6,000gms and will this fill a mould with a capacity of 6,000 cubic centimeters?

It seems to me there must be a "rule of thumb" for the percentage of loss that is probably incurred, as I suspect I will finish up with less than 6,000cc.
 

The Efficacious Gentleman

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To be totally sure, you can make some batches and see if it is more or less than what you want. As you say, trying to calculate it won't ever be 100% spot on to the nth decimal point because of evaporation, amounts left in containers/on utensils and so on. Some things are sure - 6kg is far too big a batch for you to be making at this point and 6kg of batter != 6,000 cubic centimeters, as was already explained to you the conversion between weight and volume is only 1:1 with the water. Even a saline solution will not be 1:1 weight:volume. Lye solution is not 1:1, either.
 

topofmurrayhill

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I am confused about how to add up the total of my ingredients in Cold Processing so that I fill a mould but waste as little as possible.

So if I take 1500mls of water and add 650gms of sodium hydroxide do I get 2150 of lye or is some lost through heat?

Then if I then blend 3,700gms of oil and 150gms of essential oil with the lye, do I get a mass of 6,000gms and will this fill a mould with a capacity of 6,000 cubic centimeters?

It seems to me there must be a "rule of thumb" for the percentage of loss that is probably incurred, as I suspect I will finish up with less than 6,000cc.
The rule of thumb In English units is the mold inside dimensions L x W x H x .4 in inches gives you the weight of oils to use in ounces (note this is not the weight of soap).
 

PerthMobility

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n. Some things are sure - 6kg is far too big a batch for you to be making at this point and 6kg of batter != 6 said:
Awe, spoil sport. :( I actually have a 600cc mould which I want to use but got a bit carried away with zeros.

From your response Craig, I gather that there will not be sufficient loss of mass to concern me. So if I have a 600cc mould make a up batch with a gross mass of 600grms and it will be "close". Thanks
 
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PerthMobility

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