Very hard water

[Lynda _uk]

Hello ev1

We (hubby and I) are having some fun trying to make soap.

We need to add EDTA to reduce the amount of scum, however, we're not sure when to add it and
how much to add.

We've had a look around online and think it's 0.5% of Batch weight.

Thanks for any help you can offer

 

[IrishLass]

Yes- .5% of your total batch weight of tetrasodium EDTA is what many like myself use.

Will you be using the powdered form of EDTA, or the liquid form in 39% solution? If you're using the powdered form, the math to figure out how much powdered EDTA to use is pretty much straightforward- total batch weight X .5% = how much EDTA powder to weigh out. But if you'll be using the EDTA that's in a 39% solution form, you'll have to do a little extra math to adjust for the 39% solution. Don't let that scare you, though- the math is easy. If I can do it, anyone can. I use the liquid form and I use this 2-part equation to figure out how much of the liquid form to weigh out (the same equation works for any size batch):

1) Total weight of my entire batch in grams (not ounces or pounds) X .5% = how much EDTA in grams my batch needs. But wait- my EDTA is in a 39% solution form. What do I do? Go to part 2 below:

2) Multiply the amount of grams of powdered EDTA your batch calls for in the above equation by 2.56. The resulting sum is how much of the liquid form (in grams) that you need to weigh out for your batch.

That's all!

I add my liquid EDTA to my batch after my lye solution has been added in, or at light trace.

If you are using the powdered form, just completely dissolve your powdered EDTA in some of your water amount and add it to your batch after your lye solution has been mixed in or at light trace.


HTH!
IrishLass

 

[Lynda _uk]

Thank you Irish Lass

We are using the powdered EDTA

I'll let you know how we get on
x

 

[jblaney]

I don't mean to butt in, but wouldn't you want to multiply by .05, not .5? .5 is 50 percent.

I'm the worst at math, but this exact same calculation came up recently. One of our vendors said they would give us a discount of .5 percent if we paid within 10 days, but when I asked them about it, they told me verbally they meant 5 percent, not 50 percent.

Please let me know if I'm wrong...won't be the first time.

 

[heyjude]

I'm no math wiz either, but I believe it should be .05 also.

 

[Dorado]

0,5 % is ½% not?

 

[jblaney]

1/2% would be .005

 

[turbo]

.5% =.5/100=.005

 

[IrishLass]

Turbo is correct- .5% = .005

You can multiply your total by either one. I use my calculator when figuring my EDTA amount, and since it lets me multiply using the % sign, that's what I do.


IrishLass

 

[lsg]

.5% = 5/10% or 1/2% , .05%= 5/100%, .005%=5/1000%

http://www.mathsisfun.com/decimal-fract ... ntage.html

If you are converting decimals into percents then you move your decimal point two places to the right. So .25 would equal 25%
However if the decimal already has a percent sign next to it such as .5%, then it means it is 5/10 or 1/2 of a percent.

 

[Elfknight]

I don't mean to be rude, but wouldn't buying distilled water be cheaper and less prone to errors?
EDTA may be a common lab chemical but can't be easy to find in the real world.

Rich.

 

[IrishLass]

I buy my EDTA where I buy many of my other B&B ingredients (LotionCrafters), but it is sold by other online B&B vendors that cater to the home soapmaker as well.

Re: distilled water- Using distilled water to make your soap is definitely the best way to go in that it doesn't encourage the formation of DOS like tap water that's high in iron and/or magnesium can. However, using distilled water in the production of your soap won't prevent soap scum from forming when you bathe with your soap in your regular tap water. It would be different if you were able to also bathe with distilled water, but since that's not in the realm of possibility (at least for the majority of us), using EDTA is the way to go if you have really hard water and want to use lye-based soap.


IrishLass