I got to play with the little machine last night. Got some nice welds with
aluminum and 3/32" thoriated tungsten electrode pos. Biggest problems I had
was trying to use too much current and too long of arc. Cerium electrodes
did not like to run pos..they vaporized :) Still haven't opened the box to
see if I can bypass the diodes on the final transformer for A/C .. looks
like it should work but there are sens wires connected to the output that
may cause some crazieness?
The 1/16" electrodes work fine for steel electrode neg. They just don't
clean enough for aluminum that way and cook with the other way.
Next stage is to play with thinner pieces and see if I can do what I bought
it for. Welding lightweight materials.
Things it is lacking,
Remote current control.
HF arc starter/stabilizer
A/C or adjustable square wave.
Adjustable post flow.
A good schematic so I can go in and change things :)
Zirconium electrodes also hate DC so don't bother trying them.
I would recommend using 1.5% Lanthanated for everything.
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.
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.
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.
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.
Works for me :) I will order a box of the lanthanated Monday.
So, if I understand this footpedal concept, I would mash the pedal to start
the arc and slowly release as things heat up such that with my foot off the
pedal it is running at the current I set for the normal running? Or do I
need to set both high and low limits? I just can't see using it as the
control for the current all the time as being very stable. As you
re-position your body your foot moves around and your current goes wonky.
I really appreciate your taking the time to gude me a bit here. There are
no welding schools here or I would be there now :) The welding shops mostly
tell me it is impossible to weld aluminum with DC :)
After doing a bit of reading on the web I am wondering if this machine might
be of the "Lift arc" type rather than a scratch start? I don't think I
would know the difference really.
Thanks for the info!
The most common way to run a TIG in a shop is with a foot pedal.
In a normal TIG machine, the first bit of movement of the pedal
triggers the contactor, which deliveres welding current to the
workpiece, turns on the gas and initiates the high frequency start.
As you push down your amperage increases.
So you can start off low, and ramp up until your metal melts.
With a little practice it is quite easy to hold a very constant current
level with your foot.
The way I run a TIG when weldingh stainless steel on location is to use
the Sequencer built into my inverter machine.
I tap a button on the torch handle, and it initiates a sequence that
starts with a preflow gas purge of 1/2 second, then initiates the arc
with high freq at 5 amps, ramps up over 1 second to whatever my main
amperage is set to, and then starts pulsing per my settings.
A second tap of the button triggers the downslope over 3 seconds to 2
amps, shuts off te arc and delivers 20 seconds of post flow gas.
Now whenI owned a much simpler Maxstar 140, I just set the machine to
the amperage needed for that material, opened the gas valve in the
handle, and scratch started the arc on the metal.
I would weld along the joint until I reached the end.
I would then whip teh torch away from the weld to break the arc, return
the torch to the previous position just as fast, wait til the tungsten
had cooled, and turn off the gas.
If you don't have a foot pedal, then you need to have a pretty accurate
idea of what amperage you need for what thickness of metal.
The basic rules:
1 amp per 0.001" of thickness for steel and aluminum, flat butt weld,
full penetration, single pass.
Add 1/3 for inside corners.
Subtract 1/3 for outside corners.
Subtract 1/3 for stainless steel and titanium
Subtract 1/2 for bronze.
Multiply it by 2 for copper.
So an inside fillet weld on 1/16" Stainless steel. would be...
1/16" = 0.0625" = 63 amps - 1/3 for SS = 42 amps, + 1/3 for inside
fillet = 63 amps.
Oh and never use a filler rod thicker than your base metal if you can
Do a google-groups search on my name in the archives for
sci.engr.joining.welding and you will find all my rantings and
ravings about TIG.
There is a wealth of info there and I intend to spend a lot of time
An intersting note... People are advertising this exact welder on Ebay for
up to $699.00! Most of them were in the $400 range but man are there some
sharks in those waters <LOL>
Just fished a Earnie Ball Volume pedal out of my son's dump box.
I gave it a good washing - I think excessive drink material was a dust collector
So I scored it - It contains a high quality Pot - I haven't measured it yet.
Two phone plugs provides the three connections - or a new connector added to the
1/4" Al metal 'box'. Two U shaped turned such to have two flats outside.
It doesn't jump back when the foot is lifted - that is the why spring needed.
The pot - will be measured - just did - 100k ohm.
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer firstname.lastname@example.org
On Sat, 19 Feb 2005 12:00:39 GMT, Ernie Leimkuhler
conspicuously missing is Lincoln
It's better to be a red person in a blue state
than a blue person in a red state. As a red
person, if your blue neighbors turn into a mob
at least you have a gun to protect yourself.
As a blue person, your only hope is to appease
the red mob with herbal tea and marinated tofu.
A single stero plug would give the three connections needed and give you
disconnect for the internal pot. A couple of screws to set min max ranges
on the foot pedal and you should be there. Seems like it would be more
convienient to have the min max settings on the welder though.
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