A Math Problem...

[Badger]

Okay, I have an 8" x 8" box that I was thinking of filling about 3" full of soap. I did the math for the mold and figured I would need 76.8 ounces of oils for that space (8x8x3x.4=76.8). That much I get easy enough. When it comes to me trying to cut these bars and how many bars this should make, my brain starts hurting...

I am thinking that the bars will be 4" wide and 3" tall. Now I am trying to figure out how thick I should make the bars... I am aiming to get bars that weigh 4 ounces... according to the number of ounces of oil, I should come up with about 19 bars of 4 ounce bars... does that sound right? That would make the bars less then an inch thick. Or is something wrong with my math somewhere here?

I don't expect to get 19 bars, as I know I will have stuff on the ends that I will likely not be able to use as finished product, but would 16 four ounce bars be reasonable from that? (and I despair trying to cut the bars even vaguely evenly) Please help before my brain melts

 

[Parke Co. Grapevine]

8 x 2 = 16

Oh, planning my molds and the ounces of my recipes has often made my brain melt, also! I am not an expert or long-experienced soaper, but I think 16 bars sounds very reasonable for this mold. If you turn it out in one piece ...

8" by 8" square and cut in half down the middle, you will have

Two (2) loafs 8" long by 4" wide (assuming 3" deep, as you planned)

You may see some edges that need shaped or trimmed up, then you could cut each loaf into 1" slices. ie: eight 1" slices for each loaf.

Two loafs, 8 slices each, gives you 16 bars 4" x 3" x 1"thick.

Sound reasonable? If they are each heavier than 4 oz to start, I guess some of that will reduce during drying/curing, right?

 

[Badger]

That is what I was thinking, it was just trying to get the ounces figured out in my head that I was struggling with. I need at least 12 four ounce bars for the BB Soap Swap, Thank you very much for confirming my math was at least in the right direction

 

[lsg]

Badger, I am not good at figuring length and width of bars. There is a tutorial here about figuring the volume of oils a mold will hold, but it doesn't factor in the lye and liquid. Sorry, I can't be of much help.

 

[Shannon_m]

I'm horrible at these calculations. I end up making more than my mold will hold on purpose just to make some samples, but my cake mold stymied me. I had no idea how to figure out the calculations on a round mold nor was I really going to try lol, too lazy. So I ended up making 4 lbs and it was perfect. I had just a smidge left over for about 9 pipette samples (I discarded about another 5 or 6 pipettes worth of purple because I thought it was going to turn out brownish gray...sad panda now that it turned out purple lol).

 

[Badger]

Thank you both, I actually am good with the formula, it is just actually cutting the bars and trying to get them to be the right size that I am worried about I think that this should work out okay, I just really wish I could cut straight bars so that they would look nice for the swap, and I don't really have anything to wrap them in either.

 

[Cherry Bomb]

Thank you both, I actually am good with the formula, it is just actually cutting the bars and trying to get them to be the right size that I am worried about I think that this should work out okay, I just really wish I could cut straight bars so that they would look nice for the swap, and I don't really have anything to wrap them in either.

You can do something as easy as wrapping raffia ribbon around your soaps and printing cards with your name, ingredients, etc etc and attaching it o your ribbon. It's ok if you don't have cigar bands and such

 

[DeeAnna]

If you use only consider the weight of your oils, yes, your mold will make 19 bars about 4 ounces each. But your soap will also include the weight of your lye and some of the water too. I bet your finished, cured bars will be a good bit more than 4 oz. each.

Here's what I've been doing, and maybe you can compare your situation to mine:

My Official Cardboard Box Mold is 4 inches x 4 inches x 12 inches on the inside. I filled my "OCBM" about 2 1/4" deep with soap batter, so the volume of soap in my OCBM was 4 inches x 12 inches x 2.25 inches = about 108 cubic inches.

My recipes are based on 1500 grams (53 oz) of oils, and I use a 2-to-1 water to lye ratio (33% lye). I get 16 bars that weigh about 120 grams (4.25 oz) each. Each bar is about 3" x 2 1/4" x 1" in size.

For you to get 16 bars that weigh about the same as mine, I would think you would want to fill your 8 inch x 8 inch mold about 1 3/4 inch deep, not 3 inches. And I don't think you'll need as much soap as you think to do the job.

Hope this helps! --DeeAnna

 

[Badger]

Thank you, DeeAnna! That was really helpful! I was trying to figure out how all the math of it worked with the oils and the lye and such added, I was getting a bit flustered trying to figure out where all the oils I figured out went to.

Cherry, thank you for the suggestion of using raffia ribbon. I am sure I can make a small card of some sort, but I was not sure how to wrap it and make it look presentable. Actually, does anyone have a template for cigar bands? I could print those out on the printer and cut them out by hand, maybe?

 

[melstan775]

Here's my answer to all things math. Because I can barely count!

 

[Badger]

That looks like an awesome book!

 

[Kansas Farm Girl]

remember the formula (8*8*3*.4)= the oils. It is not the soap. because there is the water and lye too. If I were making soap with 76 oz of oils I would then add 9.7 oz of lye and 18 oz of water for a batch size of 103.7 oz of soap. if you wanted to make 4 oz bars of soap, divide 103.7/4=25.9 bars (really 26 bars, 25 of which are 25 oz and 1 at 3.9 oz). But they would not be 1" thick if you cut it into 2 loaves like suggested. And this is also before the soap cures if you cut it a day or so later. Once it cures you will lose some of the weight. That I haven't figured out yet. I have read that you get a 15% reduction during cure, I have see 11%. I have never taken the time to weight it as soon as I cut it and then again 6 weeks later to test it. If you cut it to 16 bars they would be almost 6.5 oz.and 20 bars = 5.1 oz. I hate trying to figure the perfect cut. I resort to spreadsheets and graph paper sometimes.

 

[Badger]

Yeah, I am so lost trying to figure out the numbers and getting the number of ounces and how to discount for the water in the soap and how much will evaporate during the curing process. I have been playing with numbers and trying to figure out mold sizes most of the night with the plan of ordering a mold (which I have done now). I will likely make my bars a bit larger then they need to be, because I don't want them to be too small.

 

[Cherry Bomb]

Thank you, DeeAnna! That was really helpful! I was trying to figure out how all the math of it worked with the oils and the lye and such added, I was getting a bit flustered trying to figure out where all the oils I figured out went to.

Cherry, thank you for the suggestion of using raffia ribbon. I am sure I can make a small card of some sort, but I was not sure how to wrap it and make it look presentable. Actually, does anyone have a template for cigar bands? I could print those out on the printer and cut them out by hand, maybe?

Do you have Publisher?

 

[Badger]

I have Open Office, and I downloaded the avery label program that was listed in the business section of the forum.

 

[Cherry Bomb]

Hmmmmm....OK. I have a template formulated for the size of my soap in Publisher. I don't know much about Open Office. I have read on the web about the Avery label maker and it seems to be pretty good. I also know if you have access to Microsoft this may work:

http://www.craftster.org/forum/index.php?topic=294614.0#axzz2PNAoLrJj

I had trouble with this the other day and finally figured it out. You can use this site as well as long as you order from them and I know you are like the rest of us....watching our pennies

http://www.onlinelabels.com/maestro-label-design-software.htm?search=Maestro&st=s

Sorry I couldn't help ya out more!

 

[DeeAnna]

Hi, Badger --

I woke up at 4 a.m. thinking about this thread for some reason. I realized I had written the wrong depth for the soap in your 8"x8" mold. The batter should be 1 3/4" deep not 2 3/4" deep! I edited my original post and made that correction.

If you filled your mold to a generous 2" deep, you would have a mold volume of 128 cubic inches. That would make a 4"x2"x1" bar when cut -- easy to measure. To apply the rule of thumb, take that times 0.4 to get 51.2 ounces of oils.

I would also say the bars will weigh comfortably over 4 ounces after cure -- remember that the 16 bars I have been cutting from my box mold are weighing about 4.25 oz after cure with 107 cubic inches of soap in the mold.

--DeeAnna

 

[Badger]

Thank you, DeeAnna. I am sorry that this disturbed your sleep. I know sleep for me is often at a premium, and I keep dreaming about soap lately for some reason...

 

[Badger]

Thank you for the links, Cherry. The first one should be useful to use with a free program like Scribus, which works like Publisher. I am just installing it now, so I will see how it works

 

[Parke Co. Grapevine]

Deeanna, that is a good explanation. You're right, the bars I described (16 bars, 4" x 3" x 1" each) would weigh a good bit more than 4 oz. More like 5 - 6 oz each.

I am not good at figuring this all out to the oz or gr before I begin, so I always make sure I have an extra, smaller mold(s) of some kind to hold any extra or overflow. That's always nice to make soap balls with, or small sample bars.