Trouble with Stainless MIG

Date 08-01-2007 00:07

I think you need to change welding gas to a tri - mix are 75/25 with these different gas you want have to run your welding machine so hot.

By Fredspoppy (**)

Date 08-01-2007 02:31

Mathius,
I think you are a bit short on "horsepower" with the 135. Lincoln website says it is rated at 90amp, 19volts with a 20% duty cycle. You might try getting the smallest diameter SS wire you can, using the tri-mix, and see what happens. Also you will be limited by base material thickness and surface condition. Try grinding the surface, just prior to welding, as SS has a very nice, fairly thick chrome oxide surface layer that makes it "stainless", but also has a higher melting temperature than SS itself. Wire brushing will not do anything to help this situation.

Other than the above, "more power" (as Tim the Tool Man Taylor would say) will go a long way to solving your problem.

Good Luck

By Mathius (**)

Date 08-01-2007 03:48

90 amps doesn't sound quite right. Lincoln had several different models in their 135 series. I got the biggest 110/120v I could find at the time. I bought it from Summit Racing. I won't swear to it, but I think I have an older version of this welder here: http://store.summitracing.com/partdetail.asp?autofilter=1&part=LCN%2DK1873%2D1&N=700+4294925139+4294923770+4294845435+115&autoview=sku

Unfortunately, 90% of my belongings are packed away in storage as I'm anticipating a move, so I don't have the slightest idea where my owners manual is offhand.

Anyways, lets assume we're somewhere in the 100-135 amp range.

I paid somewhere around $500 for it.

Anyways, I'll try a 75/25 mix one of these days and see what that does. I just wanted to make sure this wasn't a common problem and easily fixed. I tried reversing the polarity briefly, but that didn't really yield positive results either.

And I did grind the material before welding. I used my angle grinder to bevel the root of the weld, because I wasn't at all certain my machine could handle the thickness.

If the line ends up breaking again, I guess I'll have to go old school and break out the acetylene torches. Haven't done that in a while, but there's no 220 handy that I know of at the store, and they aren't going to let me take the line off property to go to my friend's shop and use a 220 machine.

Mathius

By DaveBoyer (*****)

Date 08-01-2007 04:44

That SS wire is only .012" thicker, but the cross sectional area is 232% as great as .023 wire. That is going to take a lot more amps. I agree with the others that You have greater chances of sucess with smaller wire and the right gass.

By Mathius (**)

Date 08-01-2007 05:49

I'll be sure to try it. I'm really more concerned though with why the wire was sputtering rather than whether or not I can really weld that 3/16" with .035 wire. I could see if there was no penetration that would be one thing, but I couldn't even get a good weld puddle going. Would argon do that to SS?

Mathius

By reddoggoose (**)

Date 08-01-2007 12:51

Mathius,

If you are concerned with penetration (who isn't?), then argon is about one of the worst choices for a short circuit transfer. High argon mixes are typically used when welding in a spray transfer. Your welder doesn't have the necessary kilowatts available to reach a spray, this limits you to a short circuit transfer. For welding steel in a short circuit transfer you will get your best penetration using 100% CO2. However, I would recommend you use a mix gas of 75% argon / 25% CO2. This will give you better penetration than 100% argon and will have a better arc and less spatter than 100% CO2. For short circuit of stainless you need to change to a 90% helium/ 7.5% argon/ 2.5% CO2. There is no such thing as a one size fits all gas. Different alloys and different applications require different gases. You might be able to get by with a .035 wire, but I am inclined to agree with the other posts suggesting a smaller wire diameter.

By js55

Date 08-01-2007 14:07

It seems to me shrinking the wire is good thought, given limited power. Going to helium will only aggravate the problem. He will destabilize an already destabilized arc, even though it will add energy to the puddle. 75/25 CO2 should work fine even on SS. Miles and miles of SS welds have been made (even in pressure retaining services) with that simple mix for short circuit.

By Mathius (**)

Date 08-01-2007 15:37

I'm sorry, I think I'm confusing some of you. I AM running 100% argon right now. My buddy runs 75/25 in his shop I will try that. Right now I"m limited to my little Lincoln and a set of oxy-acetylene.

I'm NOT worried about penetration right now, because the job is already done. If it breaks now, it breaks, and I'll have to redo it.

What I AM concerned about is why I got such an intermittent wire transfer. The gun kept sputtering, and I couldn't get a proper weld puddle to form, so I couldn't run a good bead. If that is the result of using 100% argon, then it's a simple switch. If that's NOT what's causing the problem, then I need to figure it out, because I want to be able to run a little SS.

I'm not concerned about the job that much at this point. I work for the company full time for now, and I explained to them the situation, so it isn't as if this is my primary job and they're going to fire me for shoddy work.

I'm also wondering if I should have changed the liner for the bigger wire? But I would think that I would have had issues with the wire feeding before striking an arc?

Mathius

By js55

Date 08-01-2007 15:56

I just don't see that argon is going to cause you a sputtering problem. Its ionization potential is low, and if anything, will therefore assist arc initiation. I think the earlier advice from Fredspoppy about power for the larger wire is probably your biggest concern. Your amps are low.
Also, SS wire has lower electrical conductivity than CS. So I'm guessing your sitting at a threshold, and even as little a difference as the wire dia. may seem (though Dave's 232% area change calc is significant) and the reduced conductivity is enough to push it over the top.

By aevald

Date 08-01-2007 16:16

Hello Mathius, yes, 100% argon can be a big problem. As you stated some of the "feeding problems that you encountered" may be associated with the use of straight argon and not really wire feed issues completely. Metal transfer across the arc can be influenced greatly by the addition of specific gases in gas mixes, straight argon can impede the weld metal transfer and result in the drops coming off the end of the wire in an erratic manner as the welding progresses, it can also influence how the weld puddle wets out on the material.
Liner selection can have a definite influence on weld performance, especially when using stainless wires. Too small of a liner and the slightest bend or such can impede the feed or stop it entirely. Old liners or ones that haven't been cleaned on a regular schedule can also cause issues. Many times it is suggested to use a teflon liner as they have less resistance or drag associated with feeding. Too large of a liner can be an issue many times too, as the wire tries to feed through an oversized liner it can start to develope a wave effect due to too much clearance and the natural cast of the wire will just amplify this situation. Properly sized wire guides for a given diameter of wire will increase your chances of having little or no feeding problems, as well as adjusting feed roll alignment. On solid wires, a wire wiper can be a good idea to help with keeping the liner clean and free of contaminants.
Welding with any stainless wires requires a feeder/welding gun combination to be in optimum shape to give the best results. Shortest possible whip length will help, correct tip, nozzle, liner configuration will make things go smoothly, correct feed rolls, roll alignment, wire guides, and feed roll tension is a must, and correct wire roll tension adjustment will make for a much more successful venture, wire wipers for solid wires will also help. One final little quick check that might aid in determining the condition of the feed system, with the tensioning mechanism released on the wire feed rolls, try pulling the wire out through the contact tip with a pair of pliers, you should be able to accomplish this task with minimal effort and definitely not notice any changes in the amount of effort required to do this. If you do notice problems here you will need to start with the contact tip and work your way back to the wire roll tension adjustment to determine where the problem is coming from. A few thoughts for consideration. Regards, aevald

By makeithot (***)

Date 08-01-2007 19:16

aevald, Another fine post I would have to agree with your assement, I have found also that those little machine are lacking in power they work well for the hobbyest and back yard mechanic but have little to offer in the field when you need to get some serious work done.

By reddoggoose (**)

Date 08-01-2007 16:14 Edited 08-01-2007 16:17

js55,

I disagree with the comment about helium aggravating the problem. I recently qualified procedures at my work using .035 stainless. Prior to testing welding was done with a C25 gas. The arc was not crisp and spatter was prevalent. I switched to a trimix and was able to obtain a considerably better results.

By js55

Date 08-01-2007 16:29

Reddoggoose,
I have no argument with your experience. But it is a fact that because of the high ionization potential of He that it will destabilize an arc.
And the problem here for Mathius is one of very low currents (as Fredsp[oppy indicate) of which I am assuming you didn't qualify your procedures to. Certainly more acceptable levels of current as normally used will mollify the detrimental effects of He's destabilization (which is even audible). Thats part of the reason He is so popular with Al alloys where the high thermal conductivity needs to be countered with more heat energy at the puddle. Once you overcome the ionization 'hump' it has advantages. But its more difficult to do at low amps/volts.

By 357max

Date 08-01-2007 18:47

Was an extension cord used? What size gage and length extension cord was used? What was the measured outlet voltage? What was the measured voltage at the end of the extension cord? What was the polarity; electrode negative or positive? Was a vee knurled drive roll used? Argon was not a good choice. The Helium/Argon/CO2 is a far better choice with the little machines. Argon & CO2 about (1-2%) may be used. Forget about using the teflon liner.
Question: is any electrode wire manufacturer making a stainless steel flux cored wire less than 0.045" (0.030-0.035") diameter that uses 75/25 Ar/CO2 or 100% CO2?

By Lawrence (*****)

Date 08-01-2007 19:29

Max

I've been thinking along your lines for a long time and have been frustrated.

Yes they make 0.035 Stainless FCAW that can be shielded with the gasses you mention, but the problem is that they don't sell it in an extra small reel that will fit one of those 110 Hobart Handler style mini-migs.

At least I haven't been able to find a small roll...

By js55

Date 08-01-2007 19:36

If we assume the letter setting on the power source is voltage, and that the machine is max'd out at D, I fail to see the logic in using a He based gas mix that forces you to increase voltage (2 to 5 volts according to Ed Craig) in order to get a proper operating point when you don't have any more volts to increase. And if you try and increase the current the volt amp curve says you will reduce volts. Just the opposite of what you want to do.
I understand the preference for the tri mixes, but I suspect that preference is all based upon procedures and power sources not limited in a manner in which generates this thread.
Obviously this is all based upon the idea that the ultimate power of the machine is the problem.

By reddoggoose (**)

Date 08-01-2007 20:11 Edited 08-01-2007 20:22

js55,

I understand your point with helium may require higher arc voltages, however he should be able to reach a descent transfer under 19V. I was able to qualify my parameters at 18V and about 125 amps using an .035 wire and trimix gas, granted I have more kilowatts available in my power source. Now Lincoln does not publish their volt/amp curves any where that I have found so depending on the slope of the the curve he may or may not be able to even reach those parameters, since no volt/ amp curves are available I have no way of knowing what his available short circuit current is or how much of a reduction of voltage for a given change in amperage. However, if a .030 wire is used which would be better for this machine than the .035 since it will require less amperage to clear the shorts, and Mckay gives an operating range of 14-20V @ 50-150 amps with the trimix gas. For .035 wire they give 14-22V and 60-200 amps so even that small of a machine should still be able to give an acceptable arc even though it may not have enough heat for proper fusion due to base metal thickness. I still believe believe to go with the smaller wire size and trimix gas.

This debate has intrigued me a bit. In my free time I think I will try a comparison of C25 and trimix with a .030 wire, and see which gas will allow acceptable arc characteristics at the lowest voltages and amperages.

By js55

Date 08-01-2007 20:34

reddoggoose,
Heck, thats better than I would have expected with He. I have to say that I think, without looking it up, that Mathius' machine should reach that high (135 even if its low duty cycle). But this presents a real poser, because I do believe that Fredspoppy is on to something with the overall power. But it stands to reason for me that if he can't do it with the power available He won't help. I think CO2 (due to increase doxidation of the anode) can. But hey, we learn something everyday.

By 357max

Date 08-01-2007 22:08

On these little machines, the input (primary) voltage is going to affect the output (secondary) voltage. If plugged into a 115 vac outlet and it only produces 105 vac and then an extension cord (10 gauge AWG for 50 foot is recommended fpr a 20 amp 115 vac output) that is too small is added. That would possibly drop the input voltage to something like from 105 down to 90-95 vac. The machine is rated at a certain input/primary voltage at (115 vac) and amperage (usually 20).
Therefore, if its rated output voltage is supposed to be 18 vdc it may be only 14 vdc. The input voltage is going to affect the output voltage. If you don't have it going in; there is no way to get it on the way out.
A good test is worth a thousand opinions. Use an AC voltmeter and check the input/primary voltage at the outlet then at the end of the extension cord. Then use a DC voltmeter and measure the output voltage with the machine plugged into the outlet and then with an extension cord.

By Mathius (**)

Date 08-02-2007 02:29

The main consensus seems to be that the machine just isn't powerful enough for the job. Let me pose this question then? If the machine isn't strong enough to complete a 5/32 to 3/16" weld, I could accept. But shouldn't it still run a bead ok, just have very poor penetration?

Or is the argument that given argon, and .035 wire, "D" isn't a hot enough setting to run a bead?

Seems like I should be able to run .035 wire in this box, if it's built for it. How much difference is there between heat settings for stainless and steel? Again, this is the first time I've run stainless in a MIG. When TIG welding steel vs. stainless, I personally didn't notice a whole lot of difference given the alloys I used. I did notice that steel had a lot more attractive properties, in that the filler rod wanted to "stick" in the puddle slightly, almost like the attraction you get when welding with arc rods.

And to answer the extension cord question, yes I was running an extension cord. The properties of the cord, I don't know, it wasn't mine. I do know it was quite long, but I didn't have any other options. They would not let me run the welder in the building, so I had to run it outside.

Before you guys ask, yes, I was conscious of the outdoor nature of the welds being done and was careful to try and keep the shielding gas from blowing away. When I first started, I was running about 25 on the gas, and then tried bumping it up to 45 later on to see if that changed the results. It seemed to me that my results were worse, but not by much.

Mathius

By DaveBoyer (*****)

Date 08-02-2007 03:27 Edited 08-02-2007 04:35

I think that Your machine is DEFINATLY NOT built to run short circut on .035 wire. Altho some wire manufacturer says that their wire will run at 60-200 amps, for short circut there is the need for suficient amperage to clear the short, as someone has mentioned. This is much higher than the average amperage. I think for .035 wire that number is over 200 amps, and I am sure someone will come up with an acurate value. This is needed only for an instant, but the short circut must clear for the arc to start or resume. Your machine hasn't got enough amperage to clear the short with .035 solid wire. It probably works fine with .035 self shielded, but that is a different kettle of fish. The extension cord is an issue. Did Your machine come with the goofy 20 amp plug? if it does, the cord should be #12 wire minimum. Even if that machine came with a standard 15 amp plug the #12 cord is a good idea, and keep it as short as possible. For an experiment You might try .035 solid steel wire and what ever gas You normally use, and see if it works any better.

By reddoggoose (**)

Date 08-02-2007 13:09

If you look closely at the literature that Lincoln puts on its website for their SP135 amp machine, you will see that they say "Designed to FEED .023-.035 mild and stainless MIG wire". Nowhere does it say, weld with up to .035 stainless MIG wire. Maybe a point of technicality, but this is where the marketing department puts their spin on equipment. It does feed the wire but may be under powered to weld with an .035. l think you may be able to get it to run the .035 but you will be reaching the upper limits of the machine and the lower end of the wire capabilities, which will give you a very small window of operation. Your best bet is to move to a smaller wire diameter that will give you a higher current density on the wire. Regardless of machine size you are best off to not use the 100% argon gas.

By 357max

Date 08-02-2007 13:49

Use a DC voltmeter; measure and set 17 to 19 load (while welding) volts (measure at the gun head and work clamp). This may not be the machine's maximum voltage setting. Set your wire feed speed to get the "HEAT" ie increase wirefeed speed to increase amperage/decrease wirefeed speed setting to decrease amperage. If your volt/ohm meter has a tong meter to measure amperage; increase wire feed speed to get 110-130 amperes (this will require a 20 amp breaker/fuse from a 115 vac outlet). If you have a single use receptacle/outlet; wire it with 10 gauge AWG wire and a 30 amp breaker/fuse.
Increases in Voltage will flatten weld face but not increase penetration. 100% argon will not wet out/flatten welds on steels or stainless steels; it requires a reactive gas mix.
BTW that machine requires 115 vac and 20 amperes to make/transform and rectify to 18 vdc at 90 amps welding output. Again, if it is not going in; it definitely ain't coming out.

By js55

Date 08-02-2007 14:08

Eureka!! Maybe. I think Dave and 357max have hit upon the clue. You're machine currently (no pun intended) probably does not have enough max current to clear the short circuit. And consistent with 357max you 'may' have it if you eliminate the extension. I still think per Allen's suggestion onthe gas, and many onthe wire, you should change gases and wire size as well. There is no reason IMO that you cannot run those sizes of welds. Its not the welds, its the energy capacity. If you have the energy you can stack the metal.