Date   : Thu, 28 Oct 2010 21:21:01 +0100
From   : pete@... (Pete Turnbull)
Subject: Reversing the Tube ULA (destructively)

Pete Turnbull wrote:

> Nor will battery acid, which is not especially concentrated sulphuric acid.

Well, for your edification and delight, I tried an experiment a little 
earlier this evening.  A small amount of concentrated sulphuric acid on 
the top of an IC had no visible effect.  I also tried conc nitric (not 
the same as fuming nitric) and conc hydrochloric, and for good measure 
also a mixture of nitric and sulphuric (that's what you use to make 
guncotton and nitroglycerine) and /aqua regia/ (the 1:3 mixture of conc 
nitric and hydrochloric acids that is almost the only acid to dissolve 
gold).  None of them made the slightest impression on an IC package at 
room temperature.  The leads, yes.  The package, no.

Battery acid, btw, is about 30% sulphuric acid in water; commercial 
grade conc sulphuric, which is what I used, is about 95%.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York