Guest guest Posted December 18, 2003 Report Share Posted December 18, 2003 >When I'm trying to duplicate a formula, one of the first things that I >do is determine the amount of water in the formula. If you know how >much water is in the formula you can calculate the percent solids. This >number is important when you want/need to duplicate any formula. > >Laboratories have special ovens and devices to determine the percent >solids in a product. But you can do the same thing using your oven. > >Step 1) find 3 or 4 small weighing boats. I use small aluminum weighing >boats. Weighing boats are usually shallow containers that are made out >of plastic, glass or aluminum. I like to use aluminum when I'm doing a >percent solids because it won't melt in the oven and they are >disposible. > >In the home, you can use small shallow Pyrex bowls or even clean metal >caps from old jars would work. > >Step 2) Determine the weight of each weighing boat. This is the Tare >Weight. > >Step 3) Add a small amount of your unknown product to each boat. > >Step 4) re-weigh the weighing boats with the product. This is the Gross >Weight. > >Now with a little math, we can tell how much product is in each >weighing boat. This is the net weight. > >Weighing Boat 1 w/o product = 9.7 grams (aka Tare Weight) >Weighing Boat 1 w/ product = 15.2 grams (aka Gross Weight) > >So, the amount of unknown product in Weighing Boat 1 is equal to the >weight of Weighing Boat 1 w/ product minus the weight of Weighing Boat >1 w/o product or 15.2 grams - 9.7 grams = 5.5 grams. This is also >called the Net Weight. > >So that means that Weighting Boat 1 contains 5.5 grams. > >You should repeat steps 1 through 4 at least three or four times so >that you will have Weighing Boats 1 through 4. > >Step 5) Next put these weighing boats on a cookie sheet and put into >oven set at 195F. > >Step 6) After 3 to 4 hours of heating, remove samples from the oven and >re-weight the weighing boats to see how much water is lost. > >Here's a real life example. I wanted to duplicate a shampoo and need to >know how much water was used in the formula. I did the testing in >triplicate. > >BEFORE HEATING > >SAMPLE 1 >Tare Wt = Weighing Boat 1 empty = 1.27 grams >Gross Wt = Weighing Boat 1 w/ shampoo = 7.14 grams >Net Weight = (Gross Wt - Tare Wt) = 7.14g - 1.27g = 5.87 grams > >SAMPLE 2 >Tare Wt = Weighing Boat 2 empty = 1.26 grams >Gross Wt = Weighing Boat 2 w/ shampoo = 6.48 grams >Net Weight = (Gross Wt - Tare Wt) = 6.48g - 1.26g = 5.22 grams > >SAMPLE 3 >Tare Wt = Weighing Boat 3 empty = 1.27 grams >Gross Wt = Weighing Boat 3 w/ shampoo = 8.97 grams >Net Weight = (Gross Wt - Tare Wt) = 8.97g - 1.27g = 7.7 grams > > >AFTER HEATING > >SAMPLE 1 >Tare Wt = Weighing Boat 1 empty = 1.27 grams >Gross Wt = Weighing Boat 1 w/ shampoo = 2.17 grams >Net Weight = (Gross Wt - Tare Wt) = 2.17g - 1.27g = 0.9 grams > >SAMPLE 2 >Tare Wt = Weighing Boat 2 empty = 1.26 grams >Gross Wt = Weighing Boat 2 w/ shampoo = 2.06 grams >Net Weight = (Gross Wt - Tare Wt) = 2.06g - 1.26g = 0.8 grams > >SAMPLE 3 >Tare Wt = Weighing Boat 3 empty = 1.27 grams >Gross Wt = Weighing Boat 3 w/ shampoo = 2.46 grams >Net Weight = (Gross Wt - Tare Wt) = 2.46g - 1.27g = 1.19 grams > >By heating these samples, we have evaporated all the water and all that >remains are the other chemicals called solids. > >If we know the weight before heating and the weight after heating, we >can calculate the percent solids for each sample, then we can calculate >the average percent solids. > >SAMPLE 1 >5.87 grams = 100% >0.9 grams = % solids >% solids = (0.9 x 100)/5.87 >% solids = 15.3% > > >SAMPLE 2 >5.22 grams = 100% >0.8 grams = % solids >% solids = (0.8 x 100)/5.22 >% solids = 15.3% > > >SAMPLE 3 >7.7 grams = 100% >1.19 grams = % solids >% solids = (1.19 x 100)/7.7 >% solids = 15.5% > >The average % solids is equal to 15.4 > >Therefore the product being tested in this example contains about 85% >water. and continues... > SO if anyone can tell me how to improve on this, if there are > ingredients I should get rid of, ingredients I should add, and > possibly percentages, to get rid of the watery rub in feel, while > maintaining the smell, I would appreciate it! The first thing I would do is get rid of Citric Acid (I doubt that the pH of your final product will exceed 7.) Rosemary Oloresin Extract (Vitamin E or mixed Tocopherols should be fine.) Ascorbic Acid (Ascorbic Acid is not stable in water.) Neem (Not needed) Black Willow Bark (I assume that Black Willow Bark is Extract Salix Nigra Extract and is being used as a preservative. I would not use this material unless you have access to a micro lab. I would not call Black Willow Bark is not an effective preservative for personal care products.) I would replace the Methylparaben and Propylparaben with Liquid Germall Plus or any established preservative systems. and rearrange the ingredient list so it begins to look like a formula: WATER PHASE Water Vegetable Glycerin Rose water Aloe Juice Witch Hazel OIL PHASE/EMULSIFIER Shea Butter Cocoa Butter Mango Butter Stearic Acid Emulsifying wax NF Vitamin E PRESERVATIVE Liquid Germall Plus 0.35% For the time being, lets assume that Rose water Aloe Juice Witch Hazel are equivalent to water. So our formula looks like this: WATER PHASE Water = X% Glycerin = 2% OIL PHASE/EMULSIFIER Shea Butter = Cocoa Butter = Mango Butter = Stearic Acid = Emulsifying wax NF = 5% Covi-ox T-50 = 1% PRESERVATIVE Liquid Germall Plus 0.35% You do the percent solids calculations and plug the percent water into the formula where it says X%. Percent Water = 100% - Percent Solids The next step will depend on your calculations. Get back to us at CosmeticInfo and we'll see if we can come close to what you are looking for in a lotion. We may have to use different ingredients. Maurice -------------------------------------------------------- Maurice O. Hevey Convergent Cosmetics, Inc. http://www.ConvergentCosmetics.com ------------------------------------------------------- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted December 18, 2003 Report Share Posted December 18, 2003 When I'm trying to duplicate a formula, one of the first things that I >do is determine the amount of water in the formula. If you know how >much water is in the formula you can calculate the percent solids. This >number is important when you Holy moley!! I'm impressed.:0) I also know why I'm not a chemist. Coral Quote Link to comment Share on other sites More sharing options...
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