So, after looking at the SP 125 Plus welder wiring diagram and
corresponding with folks here I have come up with most of the parts
necessary to build my own timing option. Using a kit from Velleman
(PMK 111) will provide the timing. It has two adjustments: Pause and
Pulse. The kit comes with pots that allow for a .5 to 5 second Pulse
and a .5 to 60 second Pause. The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder. Whenever the the timer is powered up it
pulses first so I'm going to wire the timer power to the trigger
switch. The timer power comes from a 12 volt 200 ma wall wart. By
using a double pole/double throw switch the timer can be totally
isolated from the welder even though the trigger in the handle will be
the on switch for it. So the welder will have a switch on the front
that can be set to either CONTINUOUS or STITCH. Manually stitch
welding a few minutes ago I discovered that the Pause time should be
independent of the Pulse time. What I can't tell easily is how long
either should be and what would be the minimum and maximum times. The
timer should be made such that it has enough range without having too
much so that it is easiest to adjust. I think the Spot timer is for
plug welding. By Plug welding I mean that one piece of metal has a
hole in it. This piece of metal is clamped onto another piece of metal
such that the hole is blocked at one end. Then the hole is filled by
welding. I hope I'm using the correct nomenclature. Please feel free
to correct me. Since the Velleman timer uses higher resistance to
increase the Pause time, and since it resets every time the power is
removed, a switch which disconnects the pause pot will allow it to
weld for a set time and then turn off until the power is toggled.
Anyway, here are the questions:
1) What is the minimum Pulse time.
2) What is the maximum Pulse time.
3) What is the minimum Pause time.
4) What is the minimum Pause time.
5) What exactly is the Spot timer meant to be used for when the timer
is the one provided by Lincoln. I called Central Welding, where I buy
most of my welding supplies, and they hadn't even heard of the
Spot/Stitch timer kit for the SP125, or the SP135. So they couldn't
tell me what the Spot setting was for. And Lincoln doesn't sell it
anymore. There must be someone there who knows the answer but that
someone wasn't at the Lynnwood store today.

If anybody wants me to I can post a parts list and wiring diagram when
I'm done and it's working correctly.

Thanks for reading and responding,
Eric R Snow

On Tue, 09 May 2006 17:31:34 -0700, Eric R Snow
wrote:

So, after looking at the SP 125 Plus welder wiring diagram and
corresponding with folks here I have come up with most of the parts
necessary to build my own timing option. Using a kit from Velleman
(PMK 111) will provide the timing. It has two adjustments: Pause and
Pulse. The kit comes with pots that allow for a .5 to 5 second Pulse
and a .5 to 60 second Pause. The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder. Whenever the the timer is powered up it
pulses first so I'm going to wire the timer power to the trigger
switch. The timer power comes from a 12 volt 200 ma wall wart. By
using a double pole/double throw switch the timer can be totally
isolated from the welder even though the trigger in the handle will be
the on switch for it. So the welder will have a switch on the front
that can be set to either CONTINUOUS or STITCH. Manually stitch
welding a few minutes ago I discovered that the Pause time should be
independent of the Pulse time. What I can't tell easily is how long
either should be and what would be the minimum and maximum times. The
timer should be made such that it has enough range without having too
much so that it is easiest to adjust. I think the Spot timer is for
plug welding. By Plug welding I mean that one piece of metal has a
hole in it. This piece of metal is clamped onto another piece of metal
such that the hole is blocked at one end. Then the hole is filled by
welding. I hope I'm using the correct nomenclature. Please feel free
to correct me. Since the Velleman timer uses higher resistance to
increase the Pause time, and since it resets every time the power is
removed, a switch which disconnects the pause pot will allow it to
weld for a set time and then turn off until the power is toggled.
Anyway, here are the questions:
1) What is the minimum Pulse time.
2) What is the maximum Pulse time.
3) What is the minimum Pause time.
4) What is the minimum Pause time.
5) What exactly is the Spot timer meant to be used for when the timer
is the one provided by Lincoln. I called Central Welding, where I buy
most of my welding supplies, and they hadn't even heard of the
Spot/Stitch timer kit for the SP125, or the SP135. So they couldn't
tell me what the Spot setting was for. And Lincoln doesn't sell it
anymore. There must be someone there who knows the answer but that
someone wasn't at the Lynnwood store today.

If anybody wants me to I can post a parts list and wiring diagram when
I'm done and it's working correctly.

Thanks for reading and responding,
Eric R Snow

Another name for "plug" or "spot" welding is rosette welding.

Ya don't need any electronic stuff to do this, said the congenital
EE. The timer in your trigger finger works just fine.

I've done a fair amount of both stitch and rosette welding with an
SP125+. For body work (rust work, not competition-class
restoration) I used a pneumatic punch 'n flange tool (50 bux HF) that
flanges one part and punches the other so they assemble to present a
flat surface. Stick the repair panel in place with kleeco's or
sheetmetal screws, fill the holes with MIG weld. It only takes a
couple of seconds. With a bit of practice you don't even need a mask:
just aim the gun, shut your eyes and fill the hole. One hole per
inch, takes about 5 minutes to stick in a rear fender skirt. Another
two minutes with the angle grinder to grind the weld flat, then about
a plum-sized gob of Bondo to fill the crease and it's ready for
sanding and primer. It's only a 10-year repair, but rust work isn't
often done with expectation of another decade of service.

Ya do need a mask to stitch, but the trigger finger works just fine to
accomplish the timing. A key part of the art and skill of welding
is in managing the puddle regardless of what process makes the puddle.
Gadgets work well in automated setups, but they need to be set up
right for a particular job. OK in production, but operator skill
works better in one-off or to make just a few welds in a given sit --
and the same operator skill would be required to get the production
setup working right.

Gadgets don't make good welds unless set up by a weldor, and weldors
don't need gadgets to make a few good welds.

I make no pretence of being a journeyman-class weldor, I'm an EE and
research puke by trade and training, but I weld well enough to do
what I wanna do most days.

Eric R Snow wrote:

So, after looking at the SP 125 Plus welder wiring diagram and
corresponding with folks here I have come up with most of the parts
necessary to build my own timing option. Using a kit from Velleman
(PMK 111) will provide the timing. It has two adjustments: Pause and
Pulse. The kit comes with pots that allow for a .5 to 5 second Pulse
and a .5 to 60 second Pause. The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder. [...]

For pulse, consider a 5K pot in series with a 50K pot, and for the
pause, a 10K pot in series with 100K. There's a vast number of possible
arrangements of pots and fixed resistors in series and parallel to get
different adjustment curves, but two pots in series is probably the best
way to get both fine and coarse linear adjustments.

1) What is the minimum Pulse time.
2) What is the maximum Pulse time.
3) What is the minimum Pause time.
4) What is the minimum Pause time.
5) What exactly is the Spot timer meant to be used for when the timer
is the one provided by Lincoln. [...]

I don't know these answers, and I agree with Don Foreman that
manual control is probably good enough. Imagine sitting
there impatiently waiting for the pause to time out. You might
add a foot pedal if your concern is having your hands full.

-jiw

I hope you're not replacing a 10 megohm potentiometer with a
50K ohm one and no series resistance.

While extending the pots to the front panel might work in
theory, you're doing it in a very noisy environment. It
might induce noise that will affect your timing. Those pots
need to be very close to the circuit board.

Eric R Snow wrote:
The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder.

On Wed, 10 May 2006 10:37:10 -0500, Mike Berger
wrote:

I hope you're not replacing a 10 megohm potentiometer with a
50K ohm one and no series resistance.

While extending the pots to the front panel might work in
theory, you're doing it in a very noisy environment. It
might induce noise that will affect your timing. Those pots
need to be very close to the circuit board.

Eric R Snow wrote:
The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder.
I am gonna replace the 10M with a 50K. I will have a trimmer pot is
series though. The way the timer works is that with a 10M pot the max
delay is 60 seconds plus. With a 50K it's about 5 seconds.
ERS

The only knowledge I have of stitch/spot mig, is from an aqaintence that had
those features on a Sears (Century I think) welder. He thought the sticher
was neat until his shield gas consumption hit the roof. Apparently the gas
was on all the time instead of switching on/off during the welding cycle.

That could probablly fixed with another valve and relay.

--
J Miller
"Eric R Snow" wrote in message
...
So, after looking at the SP 125 Plus welder wiring diagram and
corresponding with folks here I have come up with most of the parts
necessary to build my own timing option. Using a kit from Velleman
(PMK 111) will provide the timing. It has two adjustments: Pause and
Pulse. The kit comes with pots that allow for a .5 to 5 second Pulse
and a .5 to 60 second Pause. The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder. Whenever the the timer is powered up it
pulses first so I'm going to wire the timer power to the trigger
switch. The timer power comes from a 12 volt 200 ma wall wart. By
using a double pole/double throw switch the timer can be totally
isolated from the welder even though the trigger in the handle will be
the on switch for it. So the welder will have a switch on the front
that can be set to either CONTINUOUS or STITCH. Manually stitch
welding a few minutes ago I discovered that the Pause time should be
independent of the Pulse time. What I can't tell easily is how long
either should be and what would be the minimum and maximum times. The
timer should be made such that it has enough range without having too
much so that it is easiest to adjust. I think the Spot timer is for
plug welding. By Plug welding I mean that one piece of metal has a
hole in it. This piece of metal is clamped onto another piece of metal
such that the hole is blocked at one end. Then the hole is filled by
welding. I hope I'm using the correct nomenclature. Please feel free
to correct me. Since the Velleman timer uses higher resistance to
increase the Pause time, and since it resets every time the power is
removed, a switch which disconnects the pause pot will allow it to
weld for a set time and then turn off until the power is toggled.
Anyway, here are the questions:
1) What is the minimum Pulse time.
2) What is the maximum Pulse time.
3) What is the minimum Pause time.
4) What is the minimum Pause time.
5) What exactly is the Spot timer meant to be used for when the timer
is the one provided by Lincoln. I called Central Welding, where I buy
most of my welding supplies, and they hadn't even heard of the
Spot/Stitch timer kit for the SP125, or the SP135. So they couldn't
tell me what the Spot setting was for. And Lincoln doesn't sell it
anymore. There must be someone there who knows the answer but that
someone wasn't at the Lynnwood store today.

If anybody wants me to I can post a parts list and wiring diagram when
I'm done and it's working correctly.

Thanks for reading and responding,
Eric R Snow

On Wed, 10 May 2006 17:53:17 GMT, "John Miller"
wrote:

The only knowledge I have of stitch/spot mig, is from an aqaintence that had
those features on a Sears (Century I think) welder. He thought the sticher
was neat until his shield gas consumption hit the roof. Apparently the gas
was on all the time instead of switching on/off during the welding cycle.

That is probably the value of a stitch timer. Constant gas flow
provides more cooling between welds. If just pulsing the trigger,
you have to wait longer for the metal to cool a bit.

On Wed, 10 May 2006 17:53:17 GMT, "John Miller"
wrote:

The only knowledge I have of stitch/spot mig, is from an aqaintence that had
those features on a Sears (Century I think) welder. He thought the sticher
was neat until his shield gas consumption hit the roof. Apparently the gas
was on all the time instead of switching on/off during the welding cycle.

That could probablly fixed with another valve and relay.
I wondered what I was going to do about that. The way the lincoln
worked, as near as I can tell fgrom the wiring diagram, is that the
gas pulsed with the wire. But it may have kept the gas on all the
time. I might put in another valve that allows the gas to flow all the
time but at a reduced rate when paused.
ERS

On Wed, 10 May 2006 08:11:22 -0600, James Waldby
wrote:

Eric R Snow wrote:

So, after looking at the SP 125 Plus welder wiring diagram and
corresponding with folks here I have come up with most of the parts
necessary to build my own timing option. Using a kit from Velleman
(PMK 111) will provide the timing. It has two adjustments: Pause and
Pulse. The kit comes with pots that allow for a .5 to 5 second Pulse
and a .5 to 60 second Pause. The Pause time pot is a 10 megohm and the
Pulse is a 50k ohm device. Since the Pause pot has so much more
resistance it is very hard to finely adjust. I will be replacing it
with a 50k pot. In fact, I am going to replace both pots because the
ones in the kit are trimmer pots and I want the adjustment knobs on
the front of the welder. [...]

For pulse, consider a 5K pot in series with a 50K pot, and for the
pause, a 10K pot in series with 100K. There's a vast number of possible
arrangements of pots and fixed resistors in series and parallel to get
different adjustment curves, but two pots in series is probably the best
way to get both fine and coarse linear adjustments.

1) What is the minimum Pulse time.
2) What is the maximum Pulse time.
3) What is the minimum Pause time.
4) What is the minimum Pause time.
5) What exactly is the Spot timer meant to be used for when the timer
is the one provided by Lincoln. [...]

I don't know these answers, and I agree with Don Foreman that
manual control is probably good enough. Imagine sitting
there impatiently waiting for the pause to time out. You might
add a foot pedal if your concern is having your hands full.

-jiw

My Dan-Mig welder has Stitch/fill. In the 5 or more years Ive been
using it..the only time I used it was to learn what it was. My big
Airco Squarewave 300 Tig has stitch.. Same thing..

Im not much of a welder and will use any technique/tool that
helps..and Stitch was a solution for a problem that hasnt come up
yet.

I can see some utility value for autobody work..but where I
live..vehicles simply dont rust out....so never had that need.

Gunner


"The importance of morality is that people behave themselves even if
nobody's watching. There are not enough cops and laws to replace
personal morality as a means to produce a civilized society. Indeed,
the police and criminal justice system are the last desperate line of
defense for a civilized society. Unfortunately, too many of us see
police, laws and the criminal justice system as society's first line
of defense." --Walter Williams