Welding Tips and Tricks

I wanted to see how well my SW200 would do on thick steel. I'm using the machine just as delivered, but substituted gas lenses for the original collet body. I used 5/16 and 1/2" mild steel plate. Gas flow is 15cfh.

Below is 5/16" mild steel, outside open corner using 1/8" E3 tungsten, 1/8" ER70S-2 filler, lay wire weave, 2 passes, machine set to 200A (the max) and using about 3/4 pedal. No problem at all handling this.


The rest of the photos are 1/2" plate. First I wanted to see if I had enough current to even lay a decent bead. Using 3/32" tungsten and 3/32" filler, it's marginal even at 200A and full pedal. The bead on right is with 1s pulse, the one on left has no pulse. It's a little hard to see in the photo, but the pulsed bead is too cold, penetration is marginal and it was tough to hold a puddle. Bead on left had OK penetration but machine was maxed out.


Below is 1/2" plate lap joint, 3/32" tungsten and 3/32" filler. At 200A and full pedal the amount of filler I could deposit is small, and it was really slow going, but I would say the penetration was acceptable.


Below is the same 1/2" plate lap joint, but I changed from 3/32" to 1/8" tungsten and 1/8" filler. At 200A I used about 80% pedal to get really good penetration and deposit a good size bead.


Below is the 3/32" tungsten and 1/8" tungsten after about 2 minutes of welding 1/2" plate. The 3/32" shows a lot of degradation, but the 1/8" shows none.


My conclusion is the machine is more than adequate to weld 1/2" plate, but I need to use 1/8" tungsten. I tried both E3 and ceriated, can't tell any difference. All the photos above were with E3. The chart says 3/32" is good up to 250A, but that does not appear to hold up in my case. Perhaps with a water cooled torch it would do better. 1/8" is rated good from 250-400A, and that allowed me to get better penetration with less foot pedal, and deposit more filler. For the 1/2" plate lap joint, I would say I could probably have completed that with 6 passes, about the same as I would have used if I were stick welding. It's not possible to use pulse on plates this thick because it's too cold, no real surprise but I wanted to prove it to myself. I had a repair job last year on 3/8" to 1/2" steel, I chickened out trying to use tig because I didn't have the material handy to practice first. I'm now confident I can weld up to 1/2" if I have to. I don't like to use stick or mig for my applications because there's always something around that will burn, like hay and a barn.

Kind if surprised that that machine had the balls to do it. You mentioned you couldn't tell the difference with your tungsten and that should be that way. Tungsten selection is usually only noticeable on AC. Most tungsten on DC run the same.

You can weld thick metal like that but you need to do some DT to see what kind of penetration you actually got. The welds look good but they aren't of adequate strength for the thickness of the metal. Your welds look like they are good and strong with good re-enforcement but if you did a bend test , the welds would likely rip out at the shoulder or toe.

if it doesn't rip out on the bend test, cut and etch to see
how much or little penetration you really have before
you do a critical weld on that thickness.
craig

exnailpounder wrote:You can weld thick metal like that but you need to do some DT to see what kind of penetration you actually got. The welds look good but they aren't of adequate strength for the thickness of the metal. Your welds look like they are good and strong with good re-enforcement but if you did a bend test , the welds would likely rip out at the shoulder or toe.

I plan to take a few cross sections and do some destructive testing, but I have to wait to take it over to the community college where they have some equipment to do that. I wasn't trying to imply these welds were adequate, just that the machine is capable of performing the welds that would be necessary. I would add more passes if I were planning to put this into any kind of service.

MarkL wrote:

exnailpounder wrote:You can weld thick metal like that but you need to do some DT to see what kind of penetration you actually got. The welds look good but they aren't of adequate strength for the thickness of the metal. Your welds look like they are good and strong with good re-enforcement but if you did a bend test , the welds would likely rip out at the shoulder or toe.

I plan to take a few cross sections and do some destructive testing, but I have to wait to take it over to the community college where they have some equipment to do that. I wasn't trying to imply these welds were adequate, just that the machine is capable of performing the welds that would be necessary. I would add more passes if I were planning to put this into any kind of service.

I do welds like that, (probably alot of us do) but only on non-critical applications. I welded a 1/2" stainless column adapter to 18ga. stainless sheet at 75 amps. With that said,welding beyond a machines capability is certainly possible. You can get it to weld but you cant get it to penetrate. If you want to check it out, do a filet weld, one side only and put it in a vice and go at it with a hammer or a big pipe wrench.

Pre-heat goes a long way, regardless of the material.

If you bring that 1/2' plate up to 325-350F before putting the current to it, the difference will surprise you. I did a bunch of aluminum today, including sch. 40 3" pipe to a 150# flange. I was able to keep under about 225A even at the start, and finished closer to 160A.

Steve S

I have had that welder a week now and very very happy. I am learning aluminum TIG but great to know 1/4 inch to 5/16 is in the realm of possibility. Here is a picture of my aluminum butt joint and a T joint need to practice a bunch with filler feeding hand.

Otto Nobedder wrote:Pre-heat goes a long way, regardless of the material.

If you bring that 1/2' plate up to 325-350F before putting the current to it, the difference will surprise you. I did a bunch of aluminum today, including sch. 40 3" pipe to a 150# flange. I was able to keep under about 225A even at the start, and finished closer to 160A.

Steve S

I'll try that, thanks.

bruce991 wrote:I have had that welder a week now and very very happy. I am learning aluminum TIG but great to know 1/4 inch to 5/16 is in the realm of possibility. Here is a picture of my aluminum butt joint and a T joint need to practice a bunch with filler feeding hand.

I happened to stumble on one of Jody's videos doing a tig certification on a beveled joint on 3/8" steel. He started out using just over 100A for the root pass, gradually moving up to 175A for the cover pass. So that's within the capability of this machine.
Your aluminum looks good, I plan to try my hand soon. I agree, feeding the wire is a bit tricky. I've found that letting the wire momentarily freeze to the work while I slide my hand forward works as well for me as trying to use my fingers.