Hello tywoodby, it is very well because your particular LN-25 isn't equipped with a contactor solenoid. It is an option on many of the suitcase feeders and by the sounds of it, your "Smithsonian" candidate is one of them. A lot of the earlier voltage sensing feeders were always hot on the wire and only fed wire when the trigger was pulled. They also had options for contactor control and a gas solenoid, keyword being "options".

Could be that the input power lug has possibly grounded to the internal metal framework of the feeder as well (at least what little of it is metal. Try tracing down the electrical feed and seeing if you can find some worn or exposed parts that shouldn't be. Good luck and best regards, Allan

Tywoodby,

WELCOME TO THE AWS WELDING FORUM!!

Now, to business: 

First, that machine should have a small gauge wire coming from it that usually has a small spring clamp to attach to the item being welded.  That is in addition to your normal work lead/clamp, and electrode/gun.

Second, as Allan mentioned, that electrode will ALWAYS be HOT.  Power to it all the time.  If you don't hit the trigger to start the wire feed before getting a short stickout from the tip too close to the work it will flash back to the tip and arc out every time.  Keep the tip back a little and hit the trigger to start the wire feeding and let it push itself into the work.  Try to do this ahead of where you want the puddle to start then pull it back and weld over top of the arc strikes that are in the weld area so they are not a problem.  Or, use run off tabs. 

Third, that particular LN 25 more than likely will not run well on a machine that is not constant voltage.  D1.1 says they must be CV anyway but many older units are not.  I had a SA300 that was not.  And if the gas engine is not running really good it will surge pretty bad.  Impossible to weld good. 

Just my two tin pennies worth.

He Is In Control, Have a Great Day,  Brent

I have an LN25, probably came over on the Ark with Noah. Using an old Tweco dual shield gun, running 1/16th self shielded wire. I get everything set up right and I use maybe one tip a day, might change it once. A guy I welded with on another job kept a dump truck full of tips for his suitcase. Might not be the welder but the welder?? I've used the same tip for two days. Lots and lots of welding, not just tack welding.

You say "hot" are you talking voltage/amperage hot? How much welding lead are you running from the power source to the suitcase? Are you setting up the voltage on the analog gauge on the front of the suitcase? Or setting the power source? You will find a substantial voltage drop thru lengths of wire. I've run 400 feet of 2/0 with 7018 and set the machine around 125 and never notice a difference whether I'm running 100 feet of lead or 450'.

On the suitcase it seems it is much more sensitive. I added 100 feet and set the suitcase wire feed speed and it was super cold. I had to turn up the power source 2-3 volts to achieve the voltage I wanted at the suitcase to match wfs. I used a 20 foot 2/0 lead to connect to my suitcase, a 20 foot for the work connection. Voltage was still slightly off. Harder to read on the analog gauge but the LN25 is a tank, durable, simple, unlike the completion with the fancy digital stuff. Stick out, settings, clean weld surface? How old is the wire? Ran some stuff I bought a few weeks ago to do some practice tests and it was spattering a lot more than a good new spool.

Just my input, have talked to a few guys that go thru tips like kids in a candy store, I just think in my head, "is that normal and what I am doing is wrong?".

The non-contactor models are intended for use when a higher output / duty cycle is required.  Generally with large limited position wires on structural steel.

I was issued one and I wanted to throw that F'g thing off the building a few times per day.  With the extra expense of all the wasted contact tips a contractor model could be bought instead.... However that doesn't mitigate the reduced duty cycle of the contractor model.

tywoodby are you the contractor.

   M.G.

When you are not welding and press the trigger do you hear a "clicking" sound from the LN? If you do not and you only see the wire feeding out then it is likely that the unit that you are using doesn't have a contactor kit in it and that is the reason for the wire always being hot. This cannot be changed without installing a contactor kit.

The reason for that extra "ganky" wire is that the feeder uses welding current to drive the feed unit and also how it keeps the wire feed speed constant when you are using a CC welding power source, hence the term: Voltage Sensing Feeder. This is also how the feeder provides "constant" wire speed by internally increasing wire speed when the arc voltage goes up (as arc length increases) and slows it down when the arc voltage goes down (arc length decreases). Best regards, Allan

Al, the OP did say that he was using a CV machine. He just hasn't really spelled out how his particular LN-25 is equipped option wise (contactor/gas solenoid). Best regards, Allan

The old LN-25s I used years ago had a contactor switch installed, but would act as you described when the contactor failed.
Hey Guys, how can he find out if there is a contactor installed on his machine?

Tim

Your ln25 probably doesn't have a contactor. You can get a tip protector that screws on and is insulated.

A lot of the engine drive machines that are made to run a wire feeder have a " contactor" built into them......Lincoln D-10's and Ranger 250 DLX's( all now discontinued ) And in Blue 350 Pros have a on/off switch for "built in contactors"