In article , David Nebenzahl wrote:
On 7/26/2010 10:30 AM Meat Plow spake thus:

On Mon, 26 Jul 2010 17:57:25 +0100, Arfa Daily wrote:

"Joe" wrote in message

...

In one of the posts about solder, somebody mentioned CVS Drug Store for
91% isopropyl alcohol.

I just called a CVS, it's $2.79 for 16 ounces and $2.99 for 32 ounces.
That's 20 cents more for double the 16 ounce size. (This is in southern
California).

91% IPA is not usually considered to be 'electronics grade', which
should be 99.7% minimum. It's also not the most appropriate stuff for
cleaning a lot of flux, which requires a proper defluxing agent such as
Electrolube Deflux 160

91 leaves a bit of residue in certain cases. After reading the
ingredients on a can of Flux-Off spray flux stripper I thought why not
just use 91 isoprop. It usually does work in conjunction with a
toothbrush. But like I said can leave a residue.

Why mess around with isopropyl alcohol at all, since all of it contains
*some* water? Use denatured alcohol (methanol) instead, in a
tightly-capped container to guard against absorbing moisture.


That would be fine if you used it in ZERO humidity.
Its not worth the trouble using 99.99%
95% is a very good figure. I actually use the NON-denatured stuff.
I don't buy it, but the medical labs buy it.. Its safer than 99%
stuff due to dryers contamination as far as drinking. The
The denatured stuff probably has more residue.

Seems to me methanol has the ability to harm some materials
its used on.


I also have a 4L bottle of isoproypal 99.5% .001% residue
which is nice. I will ALWAYS have water on the board
after cleaning just from room humidity. I usually take
a hot air gun or pistol to heat dry the board
or put it under an incandesant light bulb.

A possible source for cleaning boards, gas tank alcohol, "dry gas"
probably mostly isopropal alcohol, probably 98% or better.

greg