Loose Powder Formulation Feedback

Based on your formula and the staff's response, here is an analysis and answers to your questions:

1. Formula Adjustments

The staff correctly pointed out that the total amount of liquid oils (Fractionated Coconut Oil, LipidSoft™ Palm, and Vitamin E) in your formula is quite high (7%). Incorporating this much liquid into a powder formula, especially when mixing by hand with a mortar and pestle, is very difficult. It will likely result in clumping and uneven distribution, making it hard to achieve a smooth, uniform powder.

• Recommendation: If you are using a high-speed blender designed for powder mixing, you could potentially keep a small amount of oil (totaling no more than 3% as suggested by the staff) to help with binding and feel. However, if you are using a mortar and pestle, it is strongly recommended to remove all liquid oils from the formula. Powder formulas are inherently anhydrous (water-free), and adding liquids without proper high-shear mixing equipment will compromise the texture and performance.

2. Preservatives in Loose Powder

You asked if one preservative is sufficient and why some brands use multiple.

• Using a combination of preservatives, like the parabens and Sodium Dehydroacetate found in some commercial products (e.g., Laura Mercier), provides broader protection against a wider range of microorganisms (bacteria, yeast, and mold). Each preservative has a different spectrum of activity.
• However, as the staff explained, preservatives are generally not necessary in a purely anhydrous powder formula because microbial growth requires water.
• Major brands often include preservatives as a safeguard against potential microbial contamination introduced by the user (e.g., moisture from skin or a damp puff).
• For a homemade product for personal use, if you ensure the powder remains dry and is stored properly, you can likely omit the preservative like Phenonip® P4. Preservatives must always be used within recommended and regulatory limits, as excessive amounts can indeed be toxic or cause irritation.

3. Mixing Liquids and w/w Conversion

You asked about adding liquid ingredients like Fractionated Coconut Oil and how to convert ml to w/w.

• Mixing Liquids: As discussed in point 1 and highlighted by the staff, adding liquids to a powder formula is challenging without high-speed mixing equipment. A mortar and pestle will not effectively disperse the oils, leading to clumps.
• w/w Conversion: To convert a liquid from milliliters (ml) to grams (g) for a weight-by-weight (w/w) formula, you need to know the density of the liquid. The formula is:
  Weight (g) = Volume (ml) × Density (g/ml)
  You would need to find the density (specific gravity) of each liquid ingredient. However, given the difficulty of incorporating liquids with your mixing method, focusing on the mixing technique and potentially removing the liquids is more critical than the conversion calculation in this case.

4. Mixing Iron Oxides with a Mortar

You asked if you can mix Iron Oxides using a mortar and pestle.

• Yes, you can mix Iron Oxides, Ultramarine Pink, and other color pigments using a mortar and pestle.
• However, as the staff mentioned, this method requires significant time and effort to ensure the pigments are fully dispersed and evenly distributed throughout the powder base. Iron Oxides, especially the ultra-fine, methicone-coated types you listed (Iron Oxides Red, Iron Oxides Yellow, Iron Oxides Black), can be prone to clumping. Achieving a streak-free, uniform color will be challenging and time-consuming compared to using pigments designed for easier dispersion (like "EasyMix™" types) or using mechanical mixing equipment.

In summary, the primary adjustment recommended for your formula, especially if using a mortar and pestle, is to significantly reduce or eliminate the liquid oil components to ensure a smooth, well-mixed powder. Preservatives are generally not needed in anhydrous powders but are added by brands as a precaution against user contamination. Mixing colors with a mortar is possible but requires considerable effort for even dispersion.