Re: Home-built EDM

I just completed construction of a home-built EDM from
an article by
Arnold Gregrich in Home Shop Machinist
(October/November 2002).
The initial test results were disappointing to say the
least. Using
plain tap water, I could hardly get any sparking at
all. When it did
spark, there didn't seem to be enough power to start a
hole, much
less burn clean through a piece of 1/16" thick steel. I
changed over
to deionized water with no real improvement. The sparks
seem to
wander and not concentrate in one area.

Rich


First I have no experience with EDM. Though I do have
excellent experience in getting water to conduct
electricity. Simply adding table salt will
dramatically increase conductivity, say 10% by weight.
Pure water will not conduct electricity, simply test
with a multimeter. Commercially sodium potash or Lye
is used to increase electrical conductivity. In a
ratio of 30 to 50% by volume though these are caustic
solutions.

Ken
Kenneth A. Emmert