"Steve Smith" wrote in message
...


Ed Huntress wrote:

"Brian Lawson" wrote in message
.. .


Water as a dielectric won't catch fire, but doesn't carry heat and

swarf as well either.



Well, actually it does conduct heat much better than oil. But you need a
power supply designed for it, and it has its limitations in sinker-type
EDM
work. I doubt if you could run a D10 with water...at least, for very
long.

--
Ed Huntress


Ed and whoever else wants to chime in,

I'm starting in to make an edm, following this guy's approach:
http://www.lindsaybks.com/bks9/edm/
This is really a well thought out book and a nice simple edm design for
the home shop. Not like I have a specific task in mind for it, but it
looks like a fun project.

I have been a bit concerned about the fluid. Since I'm an electroniker,
I have to ask--what kind of power supply works best with water? If you
can, give me the electrical particulars; timing, dutycycle, voltage etc.

That machine looks like a great project, Steve. One or two other people who
have stopped in here were building those things. I'll be really interested
in how they work.

As for water dielectric, you'll need to get an update from somebody else. As
with many things, my info is historical and fading fast. g

Here's some 20-year-old info: Water dielectric allows fast cutting but it's
hell on electrodes. As of today (20 years ago g), it was restricted to
wirecut and to fast hole eroding, with wire-like electrodes that you plunge
with a lot of flushing. The water has to be deionized, although there have
been a variety of snake-oil additives that supposedly speed cutting and
which allow a lot of current flow.

I don't recall how wire EDM or hole-poppers were set up in terms of power
supply parameters. That's stuff I've long since forgotten. IIRC, the machine
you're working on is an RC relaxer circuit. If you want to try water, there
are only a few things you can adjust, so I'd just have at it.

Wirecut is a lot older than many people realize, BTW. Andrews Engineering
had a wirecut attachment back around 1958 or '59. Charmilles may have had
one earlier, and I know that Elox was working on it at least by 1960.

Agie put the pieces together with CNC and made the whole thing practical,
around 1971 or so.

Excuse me for going off on an historical tangent...

--
Ed Huntress