In article , Glenn
wrote:

Thanks Ernie,
What would the advantage of Lanthanated be over Thoriated in the same size
for DCEP? I would have to order the Lanthanated as it is not stocked in
either of the 2 welding stores here in town.


I have run DCEP on aluminum for the last 7.5 years at school , showing
my students where aluminum welding started.
I find that Lanthanted tungstens work better than any other type for
DCEP.



As far as the foot pedal all I need to decide is if I want it to be a set
lower power with your foot off so you would push down to start the arc and
release to go to your set welding power or full power with no pressure (or a
set max) and decrease with pressure. The electrical part is no problem. It
is the practical part that has me hangin fire right now.


A foot pedal that decreases your power as you push would be the reverse
of every TIG I have used, but I suppose it may work.


And Tom,
I can email a schematic or post it to the drop box. Gotta warn ya though it
isn't much of a schematic. The entire control board is a black box and the
inputs/outputs are not even named. I do plan to open it up and see if I can
get more info from the board and could send pics of that later too. I plan
to install a foot switch and see about wraping an HF tickler around the
output filter inductor. I want to look into bypassing the output diodes as
well but it may not be as simple as it seems. It appears to have some
feedback leads from the output that may be messed with if it is outputing
A/C. It appears they are sensing voltage rather than current though so it
may not matter. Then there is the matter of the big inductor that needs to
be gone for A/C and since that is the best place to hang an arc stabilizer
coil I will have to couple that up some other way.
Send me an e-mail and I will send you a scan.

Glenn

"Ernie Leimkuhler" wrote in message
...
In article , Glenn
wrote:

SNIP
Zirconium electrodes also hate DC so don't bother trying them.
I would recommend using 1.5% Lanthanated for everything.

SNIP

Things it is lacking,
Remote current control.

You could go with a mechanical system .
A foot pedal with a brake bicycle brake cable attached that spins the
amperage knob on the machine.

If you want to make a electric foot pedal try a $20 guitar volume
control foot pedal.
Just add a return spring.