Can't seem to get LN-25 to work right

Date 02-23-2008 06:26 Edited 02-23-2008 06:38

Hello Lincolnman, from the description that you just gave of your set-up you are running gas-shielded dual shield wire, generally this is run on reverse polarity(feeder+. ground-). With the CV box connected and operational set the internal switch on the LN-25 to the CV position, set the external polarity on the face of the LN-25 to the + position and connect the output from the SA250 with the + output connected to the LN-25 and the ground clamp connected to the - output terminal on the SA250. This will result in a DC reverse polarity current selection which is what the wire that you described should be run on. Now go to setting your voltage and wire speed to end up with the correct bead profile and form. The voltage setting will depend on the diameter of wire that you are running as well as the wire feed speed, take a look at the suggested parameters recommended by the particular wire manufacturer of your wire and take fine-tuning it from there. Good luck and best regards, aevald WHOA, let me back-up for just a moment, you also mentioned something about using shielding gas on innershield wire, DON'T DO IT!!! Be sure that any flux-cored wire that you run with a shielding gas is in fact a dualshield wire that is designed to be run with external gas. If it is a gasless flux-cored wire(innershield, trade name from lincoln) then it IS NOT designed to be run with a shielding gas and doing so can cause some real metallurgical issues. Even the wires that specify using a shielding gas sometimes will have designations for the type of gas to be used. Some are designed to be run strictly with 100% CO2, others are designed to only be run with 75%argon/25%CO2, still others will give you the choice of running either of the two gases that I previously mentioned. There are a few of the dual shield wires that specify using 90%argon/10%CO2, but there aren't many of these. Try to find out for sure for whatever wire you are using whether in fact this wire is a gasless flux-cored wire or if it is a flux-cored wire that requires a shielding gas and then determine the correct shielding gas, also pay close attention to the polarity that is specified for the wire, most gasless flux-cored wires are run on straight polarity, to my knowledge all of the gas-shielded wires are run on reverse polarity.

By Lincolnman Date 02-23-2008 14:34

Thanks a million I'm about to go try your advice out. And I'm also gonna check on the wire/shieding gas situation. I'll check back later and let you know what I come up with. Thanks again, Lincolnman.

By weldgault (**)

Date 02-23-2008 16:13

Give us the AWS classification and we can tell you for sure which FCAW wire it is. There should be a label on the spool or the box it came in. John

By Lincolnman Date 02-24-2008 05:00

I had mentioned that I was using 71M in my posting but I also made mention about an innershield switch n the CV box. I guess that may have lead to some confusion. It is in fact Lincoln Electric 71M outershield, .045. The label says gas shielded cored wire. I also looked further and found the classifications and they specify DC+ polarity.

Conforms to AWS A5.20-95 and ASME SFA-5.20
Classifications E71T-1 and E71T-9 DC+ polarity (DCEP)
Certified by CWB to CSA W48.5-M E4801T-9-CH

Anyway I didn't get to try out yall's advice yet had family things to do but I will try it tomorrow. Thanks again your advice has already enlightened me. I just really needed my memory jogged to remember some of this. I am like a sponge so again, any tips or advice I readily welcome. Thanks, Lincolnman.

By weldgault (**)

Date 02-24-2008 11:21

One word of advice on Lincoln Cored wire. Don't use a close ESO, they will Wormtrack. 3/4 to 1" is the best for these wires. A very long explination is necessary about this, if you need more. John

By Lincolnman Date 02-24-2008 14:20

What is ESO? I think your talking about the distance or length you keep your wire from tip of gun to the arc. I think. And if you have time you may elaborate on the worm tracking. I'm pretty sure I know what that is (little "tracks" that look like what an invisible super heat resistant little worm leaves in the weld bead). I've had it happen before and was frustrated about what was causing it. I think I was running the same setup. Anyway if you have the time it would help to satisfy my curiosity. Thanks, Jody aka Lincolnman.

By aevald

Date 02-24-2008 18:19 Edited 02-24-2008 19:42

Hello Lincolnman, ESO does refer to electrical stick out, which will differ from visible stick out. ESO is the distance from the end of the contact tip to the point where the wire is burning off and forming the puddle, visible stick out typically refers to the distance that is measured from the edge of the nozzle to the point where the wire is burning off and forming the puddle when welding with GMAW, or FCAW gas-shielded(dual shield process). The reason that these two can be considered different is due to the ability to recess the contact tip within the shielding nozzle on certain set-ups. Stick-out distances should be varied as suggested by the particular wire manufacturers recommendations. Short explanation of issues caused by using incorrect stick out goes something like this: stick out too short and the preheat on the wire doesn't properly allow for complete utilization of the fluxe's shielding properties, thus you can end up with porosity or possibly the worm tracks that weldgault spoke of. Generally if the stick out is too long there won't necessarily be a lot of issues with porosity or worming but you will have a more difficult time controlling where you apply the bead as the cast of the wire will make the end of the wire walk around during welding. There are more things that can be considered as effects and causes, these are generally the basic ones that you are talking about. Best regards, Allan
A bit more information in regards to Worm Tracking, there have been numerous discussions on the forum here and also in the welding community as a whole about this. Some thinking goes along the lines of moisture pick-up that is occurring due to the wire having a seam, this allows moisture to enter the fluxes in the wire over time and is also dependent on climatic conditions, high humidity, more contamination, shorter times that wires can be left unprotected, I believe we have seen suggestions for handling flux-cored wires in a fashion similar to the low-hydrogen SMAW electrodes, using ovens and regulating time from opening of new wire reels to their time of actual use. Type of wire manufacturing method is thought to have an effect, some wires are simply seamed together in a butt fashion, others are overlapped slightly, yet others and this seems to be the preferred one, have a type of lock-form seam. Another item that has been considered is the cross-sectional area of a given diameter of wire. For each wire diameter there is an optimum volt/amp combination relative to mode of transfer(different for short-arc, globular, spray) and type of shielding gas used. When volt/amp values are considerably above these optimums I have been led to believe that they can have an impact on whether worm tracks might start showing up. I have also followed some discussions where it has been stated that the all-position fast freeze wires will exhibit more of this sort of thing due to the relatively short time that the weld metal is in a state where gases can escape before solidification occurs.

By Lincolnman Date 02-25-2008 03:14

Thanks, your advice has been very helpful. I am still tweaking my setup. I kept trying everything to get the right results. But I wasn't getting anywhere. I been trying all of this on my 86' model SA-250. So, I switched to the newer 97' model SA-250 and wa-la everything started falling in place. I finally got my weld bead to look right with very little worm tracking. I only had that in a couple of places but did have a little porosity in one place (porosity may have been due to rust even though I wire brushed it with a wire wheel on my grinder). With the 97' I had the voltage control set on around 5 or 6. The meter on the LN-25 was reading 27 volts where as on the 86' model it was wide open with no apparent adjustability. If it was hooked up any way it was maxed out at 40 volts no matter what. I was able to keep it between 27 and 37 when I was using it this afternoon. So apparently I have some sort of problem with my older welder. That's just another thing to add to the list of things to do the third tuesday of next week.

At any rate, I do truly appreciate your time and help with my situation. I'll keep trudging away at it until I get it right. I'm a perfectionist so I have to have quality welds it's the only thing i have to sell so, I hae to be the best I can be at what I do. By the way My ears are open, my mouth shut and I am persistent. Jody, Lincolnman

By aevald

Date 02-25-2008 09:23

Hello again Jody, when you mentioned the fact that you have the voltage meter pegged while the LN-25 was hooked up to your 86', that tends to tell me that the CV function of this machine isn't operating correctly. This sort of characteristic is what is generally seen when a machine is operating on CC output. On CC the output will be high like that(due to the open-circuit voltage) until an arc has been struck, it will then reduce to actual welding voltage depending upon amperage, at the same time. If you have the opportunity, hook the suitcase back up to your 86' as you had before and while you pull the trigger to try to weld, note what the voltage does then. It is likely that you will see it drop somewhat, just how much will generally depend upon the settings that you have dialed up on your welding machine. I know this all sounds a bit confusing and I'm sorry for that, but those are somewhat the differences between CV or CC output as they relate to running wire with these two different types of current output. It may help to find a textbook or do some research with Google or some of the other search engines on the internet, or even go to the search function on the forum here for an explanation of the differences between CV and CC as they relate to your applications. Best regards, Allan

By Lincolnman Date 02-25-2008 12:06

Hello Allan, Thanks again. You've been a God send! I did actually have that idea in the back of my mind but it just never "materialized". I had been talking with a good friend of mine and my Dad's had worked with him for many years and he actually mentioned that he wasn't sure if the 86' worked in CV mode. I was looking at the old paper work that came with the machine and it had the schematics for how to hook up the CV box/adapter to the machine. It had something in there about a fuse or a fuse block in the circuit panel. But I only scanned through it quickly. I didn't have time to study it. All of that is more than I can handle. I try to be realistic and acknowledge my limitations. I'll probably take it over to this place in Montgomery that my Dad had used. I believe it's called The Welding Machine Hospital. Kinda funny name but I think they know there stuff there. Untill then I've got my newer machine that works fine. Thanks again Allan. I'm gonna keep researching as much as possible. AWS has a wealth of knowledge as does the Lincoln site and others. Have a great day! Jody, Lincolnman