IPA versus IMS?

[Craig]

If you are talking about traditional shellac, as is used for French polishing, IPA won't work. It needs to be ethanol in some form.

Now buying pure ethanol is not easy or cheap (now). The things to buy are either something called Finishing Spirit ( https://fiddes.co.uk/shop/accessories/ch...ng-spirit/ ), with is ethanol with a bit of shellac added, or methylated spirit (which is ethanol with additives to make it non-drinkable) - which is what I guess you must mean by IMS.

Girls used to be warned about marrying a French polisher, because they tippled the ethanol and were permanently drunk.

Craig

[ppppenguin]

IMS (industrial meths) is a lot nicer than the stuff you can buy over the counter. Both are roughly 90% ethanol, 5% methanol and 5% water. Ordinary meths has a blueish dye added plus pyridine to give it a truly horrible smell. But you need a licence to buy IMS.

[Cleggy]

I'm suspicious that the meths you buy in the DIY sheds may well have all kinds of impurities in at low levels. I don't think you see a specification for it anywhere. I tend not to use it in any radio work.

[roadster]

The last batch of "meths", which I bought from my local fibreglass supplier a few months ago, did not contain any methanol. From memory it was c.90% ethanol, c.9% IPA, c.1% MEK. I asked about the change of recipe and was told that it was to make it less toxic but still unpallatable. I guess that it should really now be called propalated spirit! When I have done french polishing, purely as an amateur and nothing critical, I have used ordinary domestic meths as a solvent. Whether or not the colouring in the meths made any difference I don't know.

[Nick]

Methylated spirits aka denatured alcohol has no internationally recognised standard - it varies from country to country - most EU states, plus the UK, have their own specific recommendations as to the formulation - so whatever the sheds bottle is what you get and that's that.

* Denatured just means made unfit for human consumption.

[ppppenguin]

Some truly fascinating bedtime reading

https://www.gov.uk/government/publicatio...ed-alcohol

[peter scott]

The amount of regulation is enough to turn anyone to drink!

[ppppenguin]

I once tried a drop of pure ethanol. Analar grade, I forget how much better than 99% pure it was. It sure burned as it went down.

[Craig]

You can get 99% ethanol with 1% MEK from a German supplier to those who manufacture and restore violins https://www.joha.eu/en/resins/natural-re...-99?number=&c=331 . That (other than finishing spirit) is definitely the stuff to use for dissolving french polish.

[ppppenguin]

I'm amazed that's legal to sell to the general public in the UK or even in Germany. 1% of MEK doesn't seem like much by way of de-naturing.

If you're a business with a non-residential address you can by absolute alchohol in the UK. Duty has been paid so it's expensive:
https://www.chemicals.co.uk/absolute-ethanol