Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
Don Foreman
 
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Default Cobramatic push-pull guns?

Rager source for replacement. So how do I know if the liner is worn
and I need a replacement?

On Fri, 19 Nov 2004 09:44:46 GMT, Gunner
wro

How do you know if the liner is worn? If it is worn, where can I
get a replacement?


http://www.mkproducts.com/



  #2   Report Post  
Old Nick
 
Posts: n/a
Default

On Fri, 19 Nov 2004 00:52:51 GMT, Ernie Leimkuhler
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Ok. I did a quick look last night.

The Posi Start (slow wire feed for the first arc start) does not work
on this machine. It has its controls blanked off.
- I am assuming that this was an option that this (ex govt) machine
did not have?

Likewise Remote Wire Feed Speed Control is blanked.
- I am not sure what this means. It worries me a bit.

The Cobra motor, surprisingly for Oz, is 115V AC. Now this is
inconvenient. I am not sure how bad.
- My MIG machine uses 240V AC, but what it feeds its _motor_ I am
not sure. There is nothing written on the motor to indicate.
- It must also feed it something to control its speeds fairly
accurately under loads, right?
- So my problem is: What controls the wire feed speed on the Cobra?
There is a little multi-turn pot on the handle of the gun. If I am
real lucky, this will synchronously control both push and pull motors,
and all I need is to find a 240-120 trannie and supply power to the
machine on the correct pin. Otherwise I can NOT run this very easily
from my machine, unless by extreme luck I have a machine that has a
15V motor.
- what worries me is the fact that there is a "Remote wire feed
speed" control option, as if there was an option to feed a signal back
to the main welder to control the speed. This means of course that the
main welder has to be able to control the speed. That could be a
bummer.


I can start asking the makers, but it's the weekend. Never buy a
strange toy on a Friday! G

Appreciate any help.

In article , Old Nick
wrote:

On Thu, 18 Nov 2004 18:35:42 GMT, Ernie Leimkuhler
vaguely proposed a theory
......and in reply I say!:

remove ns from my header address to reply via email

Thanks for the reply. Funny. Your name sprang to mind as I posted!
Can't think _why_. G

Looks like the _worst_ I can do here is buy a $200 steel box! GG

A cobramatic push pull feeder with gun sells for around $3500 new (US$)



Used ones even 15-20 years old sell for around $1000 (US$)


Holy Canola!

Thanks Ernie. I was looking through the ads for stuff like the LN25,
and I saw they were easy Aud$750-1000

Yes parts are still available for every model.


MK Products still makes them.


I was amazed at the amount of stuff on the Web about them, showing
them to be very active still. I had never heard of them. (blush!)


They are specialized machines.
You only normally see them in production shops doing a lot of aluminum
fab, like boat yards and trailer manufacturers.

They are prohibitively expensive for smaller fab shops.
Smaller shops make do with spoolguns.


You can run it from a CV power source (a 250 amp MIG or larger) or a CC
power source (a TIG/STICK machine 200 amps or larger).

Even if you can't use it immediately you can likely resell it for more
money.


Yes. I actually asked my Father to trot around and put $50 on it.
because the guy had another phone call even as I was talking to him. I
was willing to pretty much risk that $50, as I started to see what I
was looking at. Thanks for the info.

A question. I do not have a 250A MIG. I have a 220A (Migomag. Hardly
known but very heavy duty and I am happy G). I am pretty sure it
will not have the right connections for the wire feeder. Can I fix
that, or is the welder simply not suitable? I have found the
connection diag for the Cobramatic on the Web, but what is it about
the welder that will not suit? Any idea?


You can likely jerry-rig it into your MIG.
Mainly it needs to be able to trigger the contactor controller in the
MIG power source.
You hook up a heavy jumper cable for the welding current from inside
the MIG near the wire feeder to the cobra cabinet.

The gas goes directly from the flowgauge to the cobra cabinet.
You can run steel in a cobra but it will wear out the very expensive
teflon liner.


************************************************** ***
Dogs are better than people.

People are better than dogs for only one purpose. And
then it's only half of ofthe people. And _then_ most
of them are only ordinary anyway. And then they have a
headache.........
  #3   Report Post  
Ernie Leimkuhler
 
Posts: n/a
Default

In article , Old Nick
wrote:

On Fri, 19 Nov 2004 00:52:51 GMT, Ernie Leimkuhler
vaguely proposed a theory
......and in reply I say!:

remove ns from my header address to reply via email

Ok. I did a quick look last night.

The Posi Start (slow wire feed for the first arc start) does not work
on this machine. It has its controls blanked off.
- I am assuming that this was an option that this (ex govt) machine
did not have?


Posi-start is not worth the trouble anyway.
We leave it turned off on our Cobras.


Likewise Remote Wire Feed Speed Control is blanked.
- I am not sure what this means. It worries me a bit.


That means being able to set the wire speed from the cabinet.

The Cobra motor, surprisingly for Oz, is 115V AC. Now this is
inconvenient. I am not sure how bad.
- My MIG machine uses 240V AC, but what it feeds its _motor_ I am
not sure. There is nothing written on the motor to indicate.


Many large CV power sources can output 115 volt AC for motor controls.
Should be simple enough to rig up a transformer, and just plug it into
the wall.

- It must also feed it something to control its speeds fairly
accurately under loads, right?


No the power source just supplies welding power and maybe a 115 volt
source to run the feeder

- So my problem is: What controls the wire feed speed on the Cobra?
There is a little multi-turn pot on the handle of the gun. If I am
real lucky, this will synchronously control both push and pull motors,
and all I need is to find a 240-120 trannie and supply power to the
machine on the correct pin. Otherwise I can NOT run this very easily
from my machine, unless by extreme luck I have a machine that has a
15V motor.


That multi-turn pot controls the speed of both motors.

- what worries me is the fact that there is a "Remote wire feed
speed" control option, as if there was an option to feed a signal back
to the main welder to control the speed. This means of course that the
main welder has to be able to control the speed. That could be a
bummer.


I can start asking the makers, but it's the weekend. Never buy a
strange toy on a Friday! G


What you have is a standard Cobra, with no extras.



Appreciate any help.

In article , Old Nick
wrote:

On Thu, 18 Nov 2004 18:35:42 GMT, Ernie Leimkuhler
vaguely proposed a theory
......and in reply I say!:

remove ns from my header address to reply via email

Thanks for the reply. Funny. Your name sprang to mind as I posted!
Can't think _why_. G

Looks like the _worst_ I can do here is buy a $200 steel box! GG

A cobramatic push pull feeder with gun sells for around $3500 new (US$)


Used ones even 15-20 years old sell for around $1000 (US$)


Holy Canola!

Thanks Ernie. I was looking through the ads for stuff like the LN25,
and I saw they were easy Aud$750-1000

Yes parts are still available for every model.

MK Products still makes them.

I was amazed at the amount of stuff on the Web about them, showing
them to be very active still. I had never heard of them. (blush!)


They are specialized machines.
You only normally see them in production shops doing a lot of aluminum
fab, like boat yards and trailer manufacturers.

They are prohibitively expensive for smaller fab shops.
Smaller shops make do with spoolguns.


You can run it from a CV power source (a 250 amp MIG or larger) or a CC
power source (a TIG/STICK machine 200 amps or larger).

Even if you can't use it immediately you can likely resell it for more
money.

Yes. I actually asked my Father to trot around and put $50 on it.
because the guy had another phone call even as I was talking to him. I
was willing to pretty much risk that $50, as I started to see what I
was looking at. Thanks for the info.

A question. I do not have a 250A MIG. I have a 220A (Migomag. Hardly
known but very heavy duty and I am happy G). I am pretty sure it
will not have the right connections for the wire feeder. Can I fix
that, or is the welder simply not suitable? I have found the
connection diag for the Cobramatic on the Web, but what is it about
the welder that will not suit? Any idea?


You can likely jerry-rig it into your MIG.
Mainly it needs to be able to trigger the contactor controller in the
MIG power source.
You hook up a heavy jumper cable for the welding current from inside
the MIG near the wire feeder to the cobra cabinet.

The gas goes directly from the flowgauge to the cobra cabinet.
You can run steel in a cobra but it will wear out the very expensive
teflon liner.


************************************************** ***
Dogs are better than people.

People are better than dogs for only one purpose. And
then it's only half of ofthe people. And _then_ most
of them are only ordinary anyway. And then they have a
headache.........

  #4   Report Post  
Old Nick
 
Posts: n/a
Default

On Sat, 20 Nov 2004 07:48:16 GMT, Ernie Leimkuhler
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Thanks Ernie. And GOOD news as well! G
Posi-start is not worth the trouble anyway.
We leave it turned off on our Cobras.


Eeeeuw! "OUR COBRAS eh?" G Show-off! GG

But anyway, fine. I assumed it was an "unwanted extra"

That means being able to set the wire speed from the cabinet.


Yes. I was worried that it was some way to send back to the "mother"
welder. But your later comments make me feel better.

Many large CV power sources can output 115 volt AC for motor controls.
Should be simple enough to rig up a transformer, and just plug it into
the wall.


Given your news, that is what I plan to do. I have a 115V - 240 volt
trannie, and I _was_ going to use it for this "in reverse". But it's
not a proper isolation trannie, I have discovered. It is a
centre-tapped trannie. When used in reverse it will be a bit
dangerous, and gives some very suss voltages between the pins at the
115Volt end, under no load (read "if any wire ever came loose etc".)

No the power source just supplies welding power and maybe a 115 volt
source to run the feeder


That multi-turn pot controls the speed of both motors.


Ah! Now there's the GOOD news! Thank you.

I mean...I would have thanked you anyway, but it's much better this
way! G

I can start asking the makers, but it's the weekend. Never buy a
strange toy on a Friday! G


Unbelievable. I emailed them at some ungodly hour on Friday evening,
and had a reply on Saturday! These guys are really on the ball. And I
was completely honest with them about my secondhand purchase, my dodgy
setup and all. I said I would buy a manual if that would help with
setup. The guy responding has _sent_ me a manual, no charge, no
postage, and has asked what my welder is, so he can help me set it up
with the feeder. As far as it goes, you get _service_ for your money
with these guys, anyway.



What you have is a standard Cobra, with no extras.


D'Oh. I wanted the flashy bits! GG

Really apprecaite the help Ernie.
  #5   Report Post  
Phil Kangas
 
Posts: n/a
Default


"Ernie Leimkuhler"

The Posi Start (slow wire feed for the first arc start) does not work
on this machine. It has its controls blanked off.
- I am assuming that this was an option that this (ex govt) machine
did not have?


Posi-start is not worth the trouble anyway.
We leave it turned off on our Cobras.



Posi-start is rather useful when running constant current procedures,
usually with large dia. wire.





- So my problem is: What controls the wire feed speed on the Cobra?
There is a little multi-turn pot on the handle of the gun. If I am
real lucky, this will synchronously control both push and pull motors,
and all I need is to find a 240-120 trannie and supply power to the
machine on the correct pin. Otherwise I can NOT run this very easily
from my machine, unless by extreme luck I have a machine that has a
15V motor.


That multi-turn pot controls the speed of both motors.



That pot controls the pull motor in the gun, the other motor is a slave
motor of low torque to assist in feeding wire and its speed is not
controlled.


- what worries me is the fact that there is a "Remote wire feed
speed" control option, as if there was an option to feed a signal back
to the main welder to control the speed. This means of course that the
main welder has to be able to control the speed. That could be a
bummer.



Remote speed control is used when the setup is mechanized.




I can start asking the makers, but it's the weekend. Never buy a
strange toy on a Friday! G


What you have is a standard Cobra, with no extras.



Appreciate any help.





  #6   Report Post  
Old Nick
 
Posts: n/a
Default

On Sat, 20 Nov 2004 18:23:09 -0500, "Phil Kangas"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Thanks for jumping in.

Posi-start is not worth the trouble anyway.
We leave it turned off on our Cobras.


Posi-start is rather useful when running constant current procedures,
usually with large dia. wire.


Well, as I said, it's moot for me..G

That pot controls the pull motor in the gun, the other motor is a slave
motor of low torque to assist in feeding wire and its speed is not
controlled.


hmmm....OK. So this thing _has_ to run as push-pull. This makes sense
given that the motor is 115V 50 Hz AC. Not easy to control the speed
of that. I assume the gun motor must be supplied other power that can
be controlled?

Remote speed control is used when the setup is mechanized.


OK. Again moot G.


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