Density measure of solid products

Hi there!

So today I have quality control related question :D . How do you guys measure the density of solid cosmetics (e.g.: soap bars, lip balms, moisturizing sticks)? Should they be melted? I did a research in the cosmetics quality control guide of the regulatory agency of my country but they only offered vague guidelines. I'd be really grateful if anyone with experience in this topic could help me with this one. 

Thanks in advance :smile:

Kind regards. 

Comments

  • FekherFekher Member, Professional Chemist
    @tecnico3vinia as a reflection make the product in high purity Alcohol(wich has low density) determine the added volume wich is the volume of the solid then  Mesure the weight and that's all. 
  • chemicalmattchemicalmatt Member, Professional Chemist
    @tecnico3vinia Your's is a good question and worthy of an answer. In the past I've heated the product to 10C above its solidification point and measured using a heated pycnometer, posting the specification as 0.### @ 60C.  The other means is to tare a graduate cylinder, melt the product, fill to over the 100ml mark, let cool to RT then carefully shave off excess until level at the mark. Weigh, then clean out and weigh water at the mark at RT, calculate SpG.  Any discrete container can be used for this too, (i.e. a Mason jar) just be sure you mark the same volume level for water and product.
  • Fekher said:
    @tecnico3vinia as a reflection make the product in high purity Alcohol(wich has low density) determine the added volume wich is the volume of the solid then  Mesure the weight and that's all. 
    Thank you! I didn't have no idea how to measure it. 
  • @tecnico3vinia Your's is a good question and worthy of an answer. In the past I've heated the product to 10C above its solidification point and measured using a heated pycnometer, posting the specification as 0.### @ 60C.  The other means is to tare a graduate cylinder, melt the product, fill to over the 100ml mark, let cool to RT then carefully shave off excess until level at the mark. Weigh, then clean out and weigh water at the mark at RT, calculate SpG.  Any discrete container can be used for this too, (i.e. a Mason jar) just be sure you mark the same volume level for water and product.
    Thank you so much, Matt. That was really helpful.
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