Kent, out of curiosity I did a bit of online reading this morning and from what I can tell the ingredients added to the ethanol (alcohol) to make it toxic, smell bad, taste bad, induce vomiting, etc can vary by country and mfg so that it can still be used as a solvent or fuel but not a cheap source for drinking. What they add varies but the point is the same. Per the Klean Strip SDS sheet they add Methanol (methyl alcohol / wood alcohol) and Methyl Isobutyl. They don't list percentages due to trade secret needs.
As Roger and others have pointed out, there are denatured alcohol products out there that are marketed specifically for mixing with shellac. I read a few other SDS sheets and what they add varies. Mohawk adds butanol and isopropanol. Again, no percentages due to trade secrets.
The net of all of this for me is that what I buy and use has been working just fine. Dissolves the shellac quickly and I see others online using it that know a lot more about it than I do. They all have to add something to it in order to sell it. Are some additives better/worse for shellac? No idea.
As Roger and others have pointed out, there are denatured alcohol products out there that are marketed specifically for mixing with shellac. I read a few other SDS sheets and what they add varies. Mohawk adds butanol and isopropanol. Again, no percentages due to trade secrets.
The net of all of this for me is that what I buy and use has been working just fine. Dissolves the shellac quickly and I see others online using it that know a lot more about it than I do. They all have to add something to it in order to sell it. Are some additives better/worse for shellac? No idea.