How much lye with castor oil?

[nettles]

Sometimes books can be so confusing. I want to make a shampoo bar that uses some castor oil. I am using a recipe I found in a book. But because I am making a smaller batch, I had to recalculate the lye. In the book, (The Natural Soap Book) she says that going by the SAP charts, it would appear that castor oil requires less lye than other oils, but in reality, it requires MORE. So how am I supposed to figure out how much more? The lye calculators go by the SAP values. But they are not to be trusted? My head is in a whirl. I know with lye it is not exactly like making a cake. I can't calculate the lye and then throw in an extra pinch for good measure. Can anyone help clear this up for me?
Thanks, Blue

 

[heartsong]

x

.hi there!

.128 grams per oz. may i suggest you take some time and learn www.soapcalc.com it is fabulous for calculating and creating recipes and size you need. it took me awhile to get the hang of it. go thru the tutorial, it is worth the time. also, brambleberry and the sage have good automatic lye calculators.

good luck!

 

[nettles]

Thanks, Heartsong. I have everything all ready, my oils all measured out, but I was still stuck at the lye part. So I went to soapcalc like you suggested, and tried to make sense of it. I looked at it before, and thought, "Uh-uh, too confusing". But this time, I took my time. I DID manage to convert my oils into percentages, and wonder of wonders - it actually added up to 100%! I was so proud of myself! But then when I went to "Compute Recipe" the lye fields remained blank. So I gave it up (for now..) and went to Magic Mountain Sage, and whatever number it came up with is the number I am going with, and I am going to ignore the book. I will let you know. I would rather under-do the lye, than over-do it anyway.
Blue