I believe the answer is that IPA is 'loosly' Propanol whereas IDA is Ethanol + some varant of nasty to make it unsuitable for drinking – usually methanol.
The difference being methanol CH3OH, ethanol C2H5Oh, propanol C3H8OH

So a bit like butane v propane – similar properties but more combustible carbon?

pgk

IPA is no good for firing your Mamod, took me ages to get the soot off

Edited By duncan webster on 19/01/2021 16:41:14

IDA is normally denatured ethyl alcohol at about 95% pure – the rest being the denaturing chemical (often methyl alcohol plus a bittering agent – if appropriate) and water. The water is there because the ethanol is generally distilled and 95.5% is about the best one can manage by that means ( theoretical is 95.7%, IIRC).

Absolute ethanol is either produced by other means or chemically dried – hence is very expensive.

IDA is Ethanol with at least 5% wood Naptha / Meatanol or simialr.

95% IDA is 95% IDA + 5% water i.e roughly 86% ethanol, 4% Wood Napha, 5% water.

99.5% has a small quantity of water, probably through absorbtion from the atmosphere (they can't prove it's 100%)

Note that in the UK you need authorisation from HMRC to buy or keep IDA. There is a 20l per year limit for members of the public for hobby use this still needs HMRC authorisation.

Industrial Denatured Alcohol (IDA)

Industrial Denatured Alcohol (IDA)

"Meths" is completly denatured alcohol – CDA no restriction on purchase in UK. It used to be dyed purple but that requirement was dropped in 2013.

Rober G8RPI.

Edited By Robert Atkinson 2 on 19/01/2021 22:04:47

I’m sure they will make some more soon, Pete

Actually … I suspect they are about to revise the ebay price

[ it appears to fluctuate with demand ]

MichaelG.

.

https://hexchemonline.co.uk/collections/isopropyl-alcohol/products/ipa?variant=52047319942

Edited By Michael Gilligan on 19/01/2021 23:03:43