Re: [CAD_CAM_EDM_DRO] EDM Fluid

bjammin@... wrote:

> water
> purification systems, they are pre-impregnated with NaCl. That is
> substituted for ions that harden water, leaving it soft but salty. And
> conductive to precisely the same degree. If indeed ion exchange resins are
> used in EDM and exchange ions, they would do exactly the same thing. Not to
> say that water-based systems do or don't use resin beds, but if so for the
> several reasons above they don't exchange.

I think the trick is that the first ion exchange resin replaces unknown ions for
a known set of ions, which can then be scrubbed away by other ion-specific
elements.

> That's true of water and ions, but there are few ions if any produced by
> EDM in pure water. Or, where do they come from?

I think that the many trace elements present in many stock alloys may be
able to produce ions. There are a bunch of light and alkali metals that will
react instantly with water (Lithium, Calcium, Sodium, etc.). Also, the intense
electric spark that vaporizes bits of metal will also disassociate and ionize the
water. Free H and O, combined with metal at vapor temperatures, would be
pretty likely to produce a full gamut of reaction products, such as metal
hydrides and oxides. The alkali metals would produce the common hydroxides,
for sure.

Jon