I have had my Lincoln 155 for about 11 years, and it's been a great little machine. I have always done Fabrication work on my 4X4 using steel that is usually .120 wall or thicker. This little box came with .35 flux cored wire and had always done everything I needed no problem. Now with the Chevelle I have been doing a little sheet metal work, and have read that the flux cored wire burns too hot for sheetmetal, and that I would have better luck with .25 MIG wire with a 75/25 Argon/Co2 Mix. So I purchased the conversion kit, bought a bottle with gas, and finally put it all together this week. Today was the first day I was able to really play with it. Now this is going to be a little hard to explain, but I'm wondering if I have this set up right...

With the flux cored wire, the machine seemed to purr right along, making a simple consistant buzzing sound. It always made the same noise, not matter what settings I had.... The few times I tried to do sheetmetal, I had the current and wire speeds on the lowest settings, and Still burned through even 16 gauge sheetmetal.

With the Mig it's deffinately different. I just want to make sure I'm not doing it wrong. I played with both the Current, and wire speed settings along with the Gas Pressure settings. Sometimes it's very quiet, Then pops. it deffinately does not have the same buzzing that the fluxcored wire had. For the 16 gauge sheetmetal that I just made a new rear window panel, I had the current on B and the wire speed set on between 2 and 3. It actually seems to weld the sheetmetal pretty good. Sometimes it pops, and doesn't seem to spread out on the two pieces of metal very well. Unless I really crank up the current, then it blows through. On vertical welds, it the weld does not stay put like it did with the flux cored wire, it drips off, almost like it's not penetrating, but I'm not really sure...

Any advise?

Steve

Is your metal clean? You might also want to switch to a larger gas shield on the tip which allows more gas to shield the arc and provide a better, smoother weld. Another question, how far away is your welding tip from the piece? If mine is too far away the weld suffers, too close and I end up boogering up the tip. Also you want to make sure you have the tip at about a 45 degree angle and weld towards that angle, pushing the gas along your route. Hope this helps you....

Did you switch polarity on the gun and work clamp. Don't know how you do that on your welder. For gas welding the gun is positive and work clamp is negative. Flux core welding is the opposite.

Did you switch polarity on the gun and work clamp. Don't know how you do that on your welder. For gas welding the gun is positive and work clamp is negative. Flux core welding is the opposite.


Yes, I changed the polarity, the ground clamp is now negative instead of positive. There are two leads inside the box right above the gun connection that were switched.

Is your metal clean? You might also want to switch to a larger gas shield on the tip which allows more gas to shield the arc and provide a better, smoother weld. Another question, how far away is your welding tip from the piece? If mine is too far away the weld suffers, too close and I end up boogering up the tip. Also you want to make sure you have the tip at about a 45 degree angle and weld towards that angle, pushing the gas along your route. Hope this helps you....

I'm using the shield that came with the conversion kit, It deffinately has enough room around the tip to let the gas flow to the weld. There is deffinately a difference when the Gas is on/Off. I played with the gas settings yesterday and didn't find any real difference from when the pressure was set at 15 l/m to when it was set to 30l/m, so I left it at about 15. I've tried moving the tip closer, and pulling it far away, Usually 1/4" to about 1/2" works best. At first I didn't clean the metal (Didn't really have to with the Flux Cored wire, it just burned through everything) But quickly after I started, I tried cleaning both pieces and it deffinately worked better.

i have the same set up as you and the little sucker has worked great for me.i have done my floor pans,firewall/cowlsection and my door skins with bad boy.i took me a while to get my setting just right but i think i have gotten them down now.for the 18ga repo metal i use a setting of b-2.8 and for 16ga i use C-3.2.
i found when i was doing 16ga with and setting it on B the my welding where to high.so i turned it up and got a flatter weld and better penatration.see if that helps you.also as stated before make sure your welding surface is clean.good luck

i have the same set up as you and the little sucker has worked great for me.i have done my floor pans,firewall/cowlsection and my door skins with bad boy.i took me a while to get my setting just right but i think i have gotten them down now.for the 18ga repo metal i use a setting of b-2.8 and for 16ga i use C-3.2.
i found when i was doing 16ga with and setting it on B the my welding where to high.so i turned it up and got a flatter weld and better penatration.see if that helps you.also as stated before make sure your welding surface is clean.good luck

C3 for sheetmetal? Wow, I guess I'm really underpowering it... I've been doing B2ish for the 16 gauge sheetmetal... do you have any trouble with blowing through the sheetmetal on C3.2? I guess I'll give it a go. The sheetmetal welding is much easier with the MIG than with the fluxcored. I use to use power level C for 120 wall tubing and steel...

Thanks for the advise.

Steve

Steve
I have the same machine as you (Lincoln 155) and have had the gas conversion on it for years. On 16g I've been using it on B-2.8 with no trouble but am going to try the C-3 setting as suggested by wambam.
My gas unit only has 1 gage that shows me how much pressure is in my tank and I have no way to change the pressure at the gun. I'm assuming the regulator I have is pre-set from the factory.
Kim

i have used the c-3.2 setting for plug welds and it seems to work really well on my machine.when i do a plug weld i start in the center and i go in a clock wise pattern from inside out.i go pretty fast not to build up to much heat,some times i start and stop just to let it cool down a bit and hit it again.when i try this on the B setting i find my welds are way to tall and not as good penatration.so if you do try the C setting go a little faster and short bursts on the trigger.it works for me

Did you change the wire feed roller? A roller that is to large will cause exactly what you describe. Also incorrect tip on the gun will create issues when welding as well. These might sound like minor details but they do make a difference when combined.

Did you change the wire feed roller? A roller that is to large will cause exactly what you describe. Also incorrect tip on the gun will create issues when welding as well. These might sound like minor details but they do make a difference when combined.


Yes I swapped the roller to the smaller notch. I got to play with it a little more today, and seem to be getting a handle on the settings. I think my wirespeed was a little too slow, and I think that I was getting too close with the Gun allowing it to arc to the tip easier.

When you run the hard wire(mig wire) you will have better results running it downhill instead of vertical.The fluxcore will run uphill but not the mig wire.

When you run the hard wire(mig wire) you will have better results running it downhill instead of vertical.The fluxcore will run uphill but not the mig wire.


Excellent to know! I always had better luck welding uphill with the Fluxcored wire... So with Mig, Downhill is better huh.... I'll have to give that a go.... Thanks for the advise!

Steve. It looks like your getting a handle on the settings. The biggest thing I found when I switched to gas was that it is totally different than Flux. Its like I had to learn how to weld all over again. The metal needs to be cleaner, The weld is colder at the same settings, The speed at which you need to move is much different. But once you get the hang of it, You can lay down some beautiful, clean welds. A friend gave me some advice on the gas pressure. He told me to set it to the lowest pressure to where it just starts to pop, Then bump it up 1psi. He said any more is just wasting gas. I run mine at 15psi and it works great for me.. Good luck..