comment on this post, here are some expanded instructions on how to make shampoo. (I'm expanding on this post - instructions for making shampoo - so I might repeat myself here.)
Instructions for making a heated surfactant mix (this applies to all surfactant based products, including facial cleansers, body washes, bubble baths, and shampoos).
1. Get your supplies ready, including distilled water. Have two Pyrex jugs ready for your ingredients.
Always choose a Pyrex jug much larger than you think you need. You'll be adding a lot of water to your mixtures, and this way you don't have to switch containers. I make sure I have a spoon and a fork at the ready, and have a spatula ready for those stubborn bits that stick to the sides.
2. Weigh out your surfactants into one container and put it into the double boiler to heat until they are easily mixed. You can add the hydrolyzed proteins, aloe vera, and every other ingredient (except the water) in the heated phase at this time.
You can use a double boiler of your choice - a pot with a Pyrex jug can work well, just make sure you put down some kind of little metal thing so the pot isn't touching the bottom. I bought mine at the dollar store. Nothing sucks more than hearing your Pyrex jug filled with exotic oils and butters go "crack" when you're making lotion!
3. Weigh out enough water, plus a little more, into a kettle. The reason we don't put the water in with the other ingredients is that there's simply so much of it and we'd have to wait a really long time for it to heat up!
4. When your water boils, add to the surfactant mixture in the double boiler and mix really well. You can remove it from the heat to mix well.
I like using forks to mix the surfactant mix. If you have access to a dollar store or a Daiso, they should have big wooden forks that can work very well for larger batches. Mixing might take a while - you do not want to get tons of bubbles. Some bubbles are inevitable. Ingredients like cocamide DEA are pretty unforgiving about adding tons of bubbles to the mix - they may never go down - while others will eventually go clear.
5. Let the mixture cool to 45˚C, then add your cool down ingredients, which include your preservatives, fragrance oils, silicones, and so on.
If you're using another thickener, especially one that requires addition to the heated phase, you really want to keep a record of how the various fragrances change the viscosity. If you're using an after-room-temperature thickener like Crothix, you can adjust the viscosity as you wish - if you're using glycol distearate, you really don't have that choice.
I like to keep a chart on my recipe sheet for each product - I put the date, the fragrance oil, and the amount used (for bubble baths I like to use 2%) then how the mixture reacts the day I make it, the morning after, and how much thickener it required. (Click here for a short post on this topic.)
For instance, Pink Sugar and Black Raspberry Vanilla thin my surfactant based products, whereas Black Amber Lavender, Lemon Curd, Hello Sweet Thang, and Jewelled Citrus all thicken (Brambleberry, Soapcraft). And remember to include the supplier for each fragrance oil - BRV from Soapcraft and Nature's Natural Solutions, while BRV from Voyageur doesn't.
Also keep a record of the clarity of your products (check out this post for more information) as some fragrance oils can make your products cloudy. When I'm using Cedar & Saffron (Brambleberry) I use cocamide DEA or glycol distearate because I won't be getting a clear product anyway!
6. Leave the mixture to come to room temperature before adding Crothix so you can see the impact of the fragrance or essential oils on the viscosity. Add it at 0.5% at a time - unless it's really watery, then start at 1%. Add at 0.5% at a time, mixing really really well before you add the next amount. 2% is generally enough to thicken any surfactant mixture, especially if you're adding aloe vera (thanks to the electrolytes).
If you're using weirdly shaped bottles, like tottles, put it into a Pyrex jug or cup to stabilize it. And buy tons of funnels - you can usually get 3 for $1.00 at the dollar or bargain store - as you'll need them for different fragrances. And throw them out the moment you can smell something on them.
8. Label your bottles with information on the batch, the fragrance, and the purpose of the ingredient. This sounds obvious, but when you've used foot lotion as facial moisturizer or bubble bath as shampoo, you'll realize it isn't easy to tell what you've made a few weeks later (especially if you have tons of bottles of different things in the bathroom!).
Spray your bottle with rubbing alcohol and wipe it off well before affixing the labels. This will make it stick better. Even though most ink jet printers offer water proof printing, the labels themselves aren't waterproof. You can spray them with that Krylon stuff (I get it at Michael's) or you can put packing tape over it.
I hope this provides you with a little more information on how I make surfactant based products.