On Wed, 4 Dec 2013, Warren Young wrote: > On 12/3/2013 22:09, Michael Hennebry wrote: >> They mention "high-purity isopropyl alcohol". >> The highest purity I've ever seen is 70%. > Bottom line: 70% is too impure for this task. > > I hesitate to use even 90% for this. The last time I used 90% isopropyl > While looking for up-to-date info on Radio Shack's web site, I came > across this relevant item: http://goo.gl/nLzub7 At $11 for a couple of > tiny bottles, both of which you have to use together, it's another 2-3x > more expensive than tape head cleaner. Plus, if you look into the MSDS, > the first part is acidic, so you must need the second pass to neutralize > what's left behind on the first pass. Sounds like a bad plan to me. For me, the bottom line is how much it will cost to clean *one* CPU/heat spreader combination. It looks like the answer is going to be a bottle I saw at Radio Shack for $11. > Everclear 190 proof should also work for this. At $20 per fifth, it > comes out under $1/oz, so cheaper than the RS fluids, but still more > expensive than the box o' isopropyl. Some households will find it a > more widely useful commodity, so there's that. :) I didn't use everclear when I did drink. > For what it's worth, you can get even purer isopropyl alcohol intended > for lab use. Prices I found online ranged from about $60-100 per liter, > or $2-3/oz, shipped. 100% is possible if you synthesize it, at even > higher cost. I'm not sure what you mean by synthesize in this context. Alternating freeze- and evaporative-distillation can get you anything less than 100%. That said, 'tain't necessarily economical. At some point, I suspect getting rid of the water through electrolysis or some other chemistry might be better. -- Michael hennebry at web.cs.ndsu.NoDak.edu "SCSI is NOT magic. There are *fundamental technical reasons* why it is necessary to sacrifice a young goat to your SCSI chain now and then." -- John Woods