Let me point out that the highest grades I have seen specified by Rio Tinto and others guarantee the sodium tetraborate decahydrate equivalent to be between 99.9 and 105 or even 110 %. That is due to uncertainty in the state of hydration. You do not know how accurately you are measuring when you measure by weight of dry powder or granules if you are looking for an accurate measurement of sodium tetraborate unless you know the exact state of hydration of all of your batch.
Originally Posted by Kirk Keyes
I don't see your argument that I do not know if I have a saturated solution. If I decant a clear liquid and cool it, I will soon know if it was saturated. If it sits long enough with excess borax at the bottom, and I stir ir periodically, I don't see how it cannot be saturated. If I weigh an accurate 4% solution to the nearest 0.1 gram I am certainly more accurate than measuring a solid whose concentration, so to speak, is not known any better than +/- 5%. The best way I can see to make sure of the state of hydration is to make a saturated solution. It must be commonly used as a method, for the weight percentage of borax decahydrate in a saturated solution is specfied vs. temperature to the hundredth of a percent in the Borax Decahydrate Product Profile by U. S. Borax.