Question About 100% Methylated Spirits

[cpsmusic]

I just bought a litre of 100% methylated spirits for use with Hard Shellac. On the bottle it says that it's 1000ml/L ethanol. If that's correct, does that mean it's actually pure ethanol? Doesn't the fact that it's called "methylated" mean that it has something in it to denature it?

[robbo266317]

Methyl alcohol was added to it years ago to deter people from drinking it, however this caused serious health problem, ie blindness etc.
Now they add a bitter chemical to dissuade people from drinking it, with a similar boiling point to Ethanol, so it cannot be distilled out.

See wiki Denatured alcohol - Wikipedia, the free encyclopedia

[cpsmusic]

Yes, I understand how it's made. It's just that if it's 1000ml/L ethanol how can it have anything else in it? Shouldn't the denaturing agent be labelled?

[robbo266317]

Try googling the brand name to see what else is in it.
If it was pure ethanol they would have alcohol tax on it at 40 %

[fubar]

my understanding is that to buy pure you need to buy from chemical supplier

[BobL]

Regular methylated spirits contains ~95% ethanol in it because it absorbs water just standing there and some water transfers across during the distillation process.

Ideally the meths used for shellac should contain no water so it is further processed to remove as much water as possible. However it is impossible to remove all water and even so called pure meths contains a small amount of water. This also is a good reason to keep lids on meths bottles used for shellac.

The amount of additives added to meths to make it toxic is very small (typically <0.25%) so the rest is usually water.

The reason they don't give exact % details for all the contents is when they make it the final amount of water remaining and additives added may vary. For stuff like meths there are rules that say provided something is less than X they don't need to say exactly what the content concentrations are.

For Shellac Meths the 1000mL/L is just a way of saying this stuff has as much water removed from it as possible.

If it says METHS on the bottle it will still contain the toxic additive. If the bottle says ETHANOL as the main descriptor then it probably wont.

[cpsmusic]

Thanks, that clears it up.

[Wizened of Oz]

Go to the maker's website and get the MSDS. That will tell you exactly what's in it without guesswork or conjecture.
You'll see that the amount of denaturing ("methylating") substances used these days is extremely small, but their names are extremely long.