Purge button added to Lincoln SP125+

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Guest

Posted: Thu May 01, 2008 2:00 pm

Greetings All,
I posted in the Metalworking.com Dropbox a text file explaining the
circuit changes to and the schematic of the Lincoln SP125 Plus welder
in order to add a gas purge button. The files begin with SP125+. I
forgot to turn on word wrap in the text file so it has really long
text lines. Oops. When viewing the tif file of the schematic using the
viewing software to blow up the image will allow the schematic to be
seen clearly enough to identify the areas mentioned in the text file.
Anyway, the circuit changes allow the switching of low voltage by the
added push button. This makes for a safer unit because the switching
of the 125 volts to the gas solenoid itself is still done by the
original factory circuitry. If you make these changes be sure to coat
any areas of exposed circuit board and components with some type of
non-conductive conformal coating similar to the factory applied
coating to prevent shorts from any conductive dust that blows through
the welder. I used clear 5 minute epoxy. Some silicone seal products
use acetic acid in the formulation. They smell of vinegar. Don't use
them because they can cause corrosion of metal inside the sealant.
ERS

Grant Erwin

Posted: Thu May 01, 2008 2:58 pm

Guest

etpm@whidbey.com wrote:

Quote:

Greetings All,
I posted in the Metalworking.com Dropbox a text file explaining the
circuit changes to and the schematic of the Lincoln SP125 Plus welder
in order to add a gas purge button.

Hey, Eric. What is the function of the "gas purge" button? You hit the button
and the gas valve opens? Closes? You want to do preflow? Postflow?

Grant

Guest

Posted: Thu May 01, 2008 9:40 pm

On Thu, 01 May 2008 19:58:24 GMT, Grant Erwin
<grant@NOSPAMkirkland.net> wrote:

Greetings Grant,
It's for pre-flow. The gas solenoid opens the valve and the gas flows
making sure your weld has shielding gas from the start. Beats feeding
wire and then clipping it off when you haven't welded for a few
minutes.
Eric

Quote:

etpm@whidbey.com wrote:
Greetings All,
I posted in the Metalworking.com Dropbox a text file explaining the
circuit changes to and the schematic of the Lincoln SP125 Plus welder
in order to add a gas purge button.

Hey, Eric. What is the function of the "gas purge" button? You hit the button
and the gas valve opens? Closes? You want to do preflow? Postflow?

Grant

SteveB

Posted: Fri May 02, 2008 12:43 am

Guest

<etpm@whidbey.com> wrote in message
news:481a7ea5.178044274@news.whidbey.net...

Quote:

On Thu, 01 May 2008 19:58:24 GMT, Grant Erwin
grant@NOSPAMkirkland.net> wrote:

Greetings Grant,
It's for pre-flow. The gas solenoid opens the valve and the gas flows
making sure your weld has shielding gas from the start. Beats feeding
wire and then clipping it off when you haven't welded for a few
minutes.
Eric

etpm@whidbey.com wrote:
Greetings All,
I posted in the Metalworking.com Dropbox a text file explaining the
circuit changes to and the schematic of the Lincoln SP125 Plus welder
in order to add a gas purge button.

Hey, Eric. What is the function of the "gas purge" button? You hit the
button
and the gas valve opens? Closes? You want to do preflow? Postflow?

Grant

I would just do what I do when I shut down the machine. Turn the speed to
zero, and hit the trigger to expel gas in the hose and pressuring the
regulator. It would work to preflow the gas, stop, then turn the wire speed
to the right place, and trim about an inch or two of wire. Not much waste
or time. But I never do anything, just fire it up and go. Guess I haven't
welded anything that critical that I noticed any deficiencies at the start
of the weld.

Steve

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