Mayday

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Mayday
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  • At this point I am just nerding out over these things, but I bought a vintage Ohaus NJ-manufactured Triple Beam Balance off eBay and it's surprisingly accurate and consistent. I'm guessing it's from the 1970s or so from how yellow and aged the instr…
  • I can't make specific recommendations, but if you're formulating anything in contact with genitals, you should be aware that there are additional areas of concern that I've come across in my own reading. Osmolarity. pH. Preservative systems hostile…
  • 25% fully dissolved at 6m30s with low speed vortex on magnetic stirrer. Most of it was already dissolved by 5m.
  • A bit unconventional, but have you tried no surfactant cleansers at all? I use gentle exfoliation with the palms of my hands under running water in the shower, and that removes all excess oil from my face. If you are not stripping any oils away, an…
  • At least 6 hours of stirring on the magnetic stirrer. Added 10% initially which dissolved quickly, then added the rest up to 35%.Looking at the solubility on PubChem again, I misinterpreted the values. It's 36.0g NaCl to 100g H20. That's actually 26…
  • (Quote) 
0.15% KSorb and 0.35% NaBenz adjusted to pH ~4.2 with HCl. Informally, neither KSorb nor NaBenz had an odor at neutral pH. After activating with HCl, only KSorb had an odor. This may just be my specific sample from Organic Creation…
  • I do not get much of an odor with 0.5% Phenoxyethanol or Sodium Benzoate (both LotionCrafter). I do get a sharp and pungent acid smell with Potassium Sorbate (Organic Creations) after activating with pH adjustment. 
  • pKa is mathematically derived from the Ka, or the acid dissociation constant. It doesn't make any sense for your overall formulation to have a pKa, since that is used to describe the strength of a single acid in solution. There may be a miscommunica…
  • (Quote) 
I now think this conclusion is incorrect given others have reported problems with precipitation while diluting a paraben stock with distilled water. My new thinking is that unless you have surfactants to help keep the parabens in so…
  • An idea, more directed at OP though: why not treat the aloe as a food product? Put it in a jar, pasteurize it, and have instructions to refrigerate after opening and a recommended shelf-life. Sodium Benzoate or Potassium Sorbate and pH adjustment t…
  • @Pharma Thanks so much for the explanation!!! I really appreciate it. I think I understand well enough, though this is the first I've heard of the octanol/water partition coefficient.My chemistry schooling is just high school and one college chemist…
  • I think if the paraben is fully dissolved (not a slurry) in the solvent, then as long as that solvent is in turn miscible in water (or soluble at that level), it should not precipitate out. I have not been able to find information about, e.g. solub…
  • Water-based personal lubricant, so it is only the water phase. Still testing gelling agents, but want to get a working preservative system defined before doing more work in that area. Not for commercial purposes at the moment.
  • @ketchito @Bill_Toge thanksI had completely forgotten about ionic disassociation in this context.
  • Thank you for that table. It's good news, actually!How I read the table: 1g EDTA-39% solution chelates 156 mg CaCO3. So if we had pure EDTA, 1g EDTA chelates 400mg of CaCO3.(Then to see how related by moles... Assuming tetrasodium EDTA—else how are …
  • Depends on the level I think.According to my municipality's water report, my tap water is 156mg/L CaCO3. Assuming 1mol EDTA can chelate 1mol Ca2+ ions (maybe wrong, too conservative?) gave me 0.07% (700ppm) Tetrasodium EDTA when I did these calculat…
  • (Quote) 
If IPBC is less than 20x more expensive than methylparaben, then the IPBC would be more economical because it's only 100ppm vs 2000+ppm. Methylparaben by itself may need to increase the concentration (to 3000ppm?) if you can't pair …
  • MakingCosmetics' sells IPBC in a propylene glycol solution.
  • According to this paper, they got a solubility of 5.947 mol IPBC/kg in ethanol at 25C. Given a molar mass of 281.03 g/mol, that gives a solubility of 167.1% in ethanol.

I don't think I'm mistaken in my interpretation, because of the…
  • Not formulating shampoo—I'm not aware of any specific considerations for shampoo over other water based formulations. I did find a warning about electrodes being damaged by detergents, particularly cationic ones. I'm impressed with the Apera PH20 f…
    in ph meter? Comment by Mayday January 27
  • One more suggestion is that you can look for patents for products containing Glycyrrhetinic Acid, and see if they describe how they formulate with it.
  • I was curious and looked into this a little but don't have an answer. The CIR assessment may be useful to you since it has some information on usage levels and solubility of the different molecules in this family.If it's soluble in acetic acid, perh…
  • On the chemistry: a lot of energy is released in that reaction, so it is not practical to reverse it. Sodium chloride is an extremely stable compound. According to the Wikipedia page, HCl is manufactured on an industrial scale directly from hydroge…
  • What about Hydroxypropyl Cyclodextrin? Would this have any effect in a stick deodorant? (Hydroxypropyl-beta-cyclodextrin is a cyclic polysaccharide that is the deodorant ingredient in Febreeze, which traps VOCs within the ring structure). With resp…
  • Ethanol and IPA reduce the surface tension of water, though I'm not sure the magnitude of effect if you already have surfactants. Or if it'll inhibit soaping in an emulsion. Anecdotally, ethanol or IPA reduces the foaming of a dilute dawn dish dete…
  • Does anyone have bad experiences with ethylhexylglycerin and know it to be the cause? There's another product I know about that caused dermatitis and I suspect it was that ingredient.
  • Found PEG-8 Dimethicone: https://www.makingcosmetics.com/ELL-PEG8DI-01.html Another thread: https://chemistscorner.com/cosmeticsciencetalk/discussion/2730/replacement-for-peg-12-dimethicone
  • The Farm Bill removed all hemp-derived products, including CBD, from the Controlled Substances Act, which criminalizes the possession of drugs. In essence, this means that CBD is legal if it comes from hemp, but not if it comes from cannabis (mariju…
  • I have lotioncrafter 90% lactic acid. I mixed 5% and 10% solutions by mass of lactate to water. Mixing 5% lactate to water: 2.50g lactate and 47.5g water. With a 90% lactate solution to start with, I mixed 2.778g lactate(90) and 47.222g additional d…
  • Could you source goat milk fat instead of goat milk? Then it would mix easily and you've included the most important part. Could you rehydrate goat milk with water and/or ethanol and then evaporate it out at low heat? Though the ethanol could curdl…
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