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Camay

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Posts posted by Camay

  1. I agree with you TallTayl, in general, but,

    1) lots of petro derived oil products are put directly on skin. Vaseline for one.

    2) The viscosities of the oils have nothing to do with saponification*. It's the ester bonds that react with the strong base. As I said in a previous post, there are few ester linked oils in motor oil (<20%), so most of the oil would go unsaponified.

    * viscosity is dependent on temperature, and the rate of saponification is also temperature dependent, assuming you have oils that can be saponified present

  2. Candle Chem is great for dyes, molds, additives, and some tools. And the guy that runs the place, Arnie, is super nice. He ships fast.

    However, I have to agree with ChrisR about the FOs. From 2006 to 2008 I tried 60 different FOs, and was not hugely impressed. I would not go so far as to say they were bad, just not incredibly strong, and not all that interesting. They sure do have a lot of them though!

    They are within driving distance for me, and I really wish they had great FOs...

  3. The the fatty acids that we use to make soap are joined to glycerol via an ester linkage. The strong base we add (lye) attackes this chemical linkage, breaks it, and makes glycerol and fatty acid salts (soap). I looked up motor oil on wikipedia:

    "The base oils of some high-performance motor oils however contain up to 20% by weight of esters"

    Only up to 20% of the oil has esters that are potential targets for the lye.

    Interesting.

  4. When I first stole my hubby's IR themometer about 4 years ago, I tested it against my tranditional, high-quality, mercury thermometer. I found the difference to be insignificant.

    Since I am usually stirring something into the wax (FO, dye, additive, etc) a steep temperature gradient does not develop from the surface of the wax to the bottom of the pour pot.

    Also, I do not think that candle-making is rocket science. The accuracy needed to for reproducing a constant product is not extreme.

  5. 76 degree coconut oil begins to melt at 76 degrees F. 92 degree coconut oil begins to melt at 92 degrees F.

    Looking around online, I've found various answers for this. Some manufacturers will claim that the difference in temperature depends on how the oil was extracted and processed. Others claim that the 92F coconut oil has steric acid added, or at least a higher percentage of steric acid than the 76F. I've also seen other waxes added to bring up the melt temp, but don't recall which waxes off the top of my head.

    This makes sense. Stearate is a saturated fatty acid. It is a chain of 18 carbons, all of which are completely hydrogenated. Its melting point is 71 C.

    Compare stearate to oleic acid, linoleic acid and linolenic acid. All are chains of 18 carbons. Oleic acid has one double bond, and its melting point is 16 C. Linoleic acid has two double bonds (polyunsaturated) and its melting point is -5 C. Linolenic acid has three double bonds, and its melting point is -11 C.

  6. Coconut oil is a mixture of triacylglycerols, which in turn, are three fatty acids linked to a glycerol backbone. This is how the plant stores fats for metabolic use. Now, those three fatty acids can be saturated or unsaturated. Saturated means that all of the carbons in the fatty acid chain are hydrogenated (as CareBear mentioned above). Unsaturated means that the carbons do not have the maximum number of hydrogens linked to them. If the maximum number of hydrogens are not present, that means that some of the carbons have double bonds to other carbons (instead of single bonds to hydrogen).

    The presence of double bonds is what actually changes the melting point of a fatty acid, or collection of fatty acids.

    A fully hydrogenated fatty acid (saturated) is an extended molecule with no double bonds in the carbon chain. Extended molecules tend to pack together very well. A consequence of close packing is a higher melting point (it takes more energy - higher temp - to "unpack" the extended chains). The more saturated fatty acids, the higher the melting point.

    On the other hand, an unsaturated fatty acid has one or more double bonds. This no longer allows the chains to take on the extended conformation; the double bond puts a kink in the chain. The kink pushes fatty acids away from one another, so they cannot pack together as well, and thus have a lower melting point. The more unsaturated fatty acids, the lower the melting point.

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