Join Date: May 2014
Methanol and nitric acid produce methyl nitrate
In strong ( greater than 10 percent volume/volume) solutions it is an explosive
So I presume this is the reason this is a restricted substance,
If you distilled off the methanol from the etchant you will end up with an explosive mixture.
Used etchant solution which has lots of metals dissolved in the solution is unstable at lower concentrations as the metals can catalyse the decomposition.
Lots on the net if you search" alcohol nitric acid solutions"
I think the advantage of using the acid in alcohol as the etching solution is there is less surface tension in the solution so it is less likely to bead on the metal surface.