--- In STMFC@..., "Bob Sterner" <rwsterner@...> wrote:

I'm not the fastest modeller in the world and and thus I always seem
to have lots of old paint that I can no longer use. I have been
fantasizing about having compressed nitrogen at my work bench so that
I could replace the atmosphere in opened paint with N2. I believe
(though don't know for certain) that this would dramatically improve
shelf life. Unfortunately, even a small cylinder ("lecture bottle")
is > $100, at least as far as I've been able to determine. If this
is a valid technique, commercial paint shops should already be on to
it. Anyone heard of anything like this?

Bob Sterner

Bob,

You might take a look at the small cans of pressurized nitrogen and
argon mix made for the yuppie oenophile (wine connoisseur) market.
The idea is the nitrogen displaces the air, then the argon settles
over the surface of the liquid. Argon is totally inert, and so
prevents any oxidation. However, the solvents in the paint will still
evaporate into the rare gas atmosphere in the bottle, so I'm not sure
preventing oxidation will make that much difference. The only way to
find out is to try it.

I just ran into a catalog page for the argon wine preserver on the
Plastic Process Equipment web site; can't figure out why, most the
people I know in the tool making and molding industries drink stronger
stuff than wine, and don't leave partial bottles around long enough
for oxidation to be a problem :-) I suspect that this stuff has
probably found some industrial uses too varied to list, possibly
conserving partially filled cans of coatings. Whatever, here's a link
to the page. I'm sure the PPE will take credit card orders.

http://www.ppe.com/08cat/1022.pdf

Or see your local wine shoppe :-)

Dennis