Welding Tips and Tricks

Hi folks, kiran from Australia. My new machine Miller Arc/Tig CST 250 Vrd is a great little unit. However I need your expert guidance on few points that I may be doing wrong. I can run 50 cm beads straight no problem with nice ripples and the next weld can be catastrophic even though it is much shorter bead like 10 cm. I am using e6013. Then I was recommended that the Millers love the e6010. This was worse with splatter.
Can someone help as e6013 causes too much slag holes: is it me, the rods or the machine? It starts ok and creates like contamination in the middle and finishes ok. Then I will grind and do it again, but same problem. If I changed the travel direction, it fixes it. What is the best rod to do vertical and Horizontal and way to do it. Sorry for the long thread but it is doing my head it and bringing my confidence low. I built trailer frame as a home based business. The 6010 rods are probably chinese; why so much splatter even temperature /amp is low. Thank you all.

"Slag holes" in 6013 usually suggests you are moving too fast. There is a great deal of difficulty seeing the difference between the puddle and the slag behind it, giving the illusion that the weld is "full" when it is not, leading you to advance too far/too fast. The color tells you very little about where the back edge of the puddle ends and the slag cover begins.

The "good" starts and stops, with trouble in the middle suggest you are close. Try intentionally overfilling a weld or two on practice pieces (slower progression), and see what the bead looks like once you chip it off.. 6013 prefers a "drag" angle, about 15 degrees, to push the slag to the rear/finished part of the weld, so you don't build it up and trap it in front of your rod.

6013 seems to perform best on AC, as it was originally designed for basic AC transformer machines, but will also work DCEP and DCEN, depending on how much penetration you need. DCEP for more penetration, DCEN for a cap pass or very thin metal.

6010, on the other hand, strongly prefers DCEP, and is intended for deep penetration. It may not be the ideal rod for trailer frames, as the deep penetration and intense heat tend to blow through thin sections. If you are getting excessive sticking spatter with the 6010, something's not quite right. One possibility is holding too long an arc (6010 like a tight arc), or possibly the polarity is wrong.

Personally, I recommend you stay with 6013 for trailer frames. Once you solve the initial trouble, 6013 is a versatile rod in all positions that will do what you need it to do.

Steve S

if you want to eliminate worm holes in 6013 rods set the machine to what you think is a good amperage then jack up the current another 15 amps. this is a good rod but not everyone takes advantage of it. you can't beat it for pipe hand-railing.

Thank you so much to both repliers. I will try the reducing the speed and let you know soon. Also, i weld so good from left to right with the 6013. So my question is when I am dragging the rod, making the ripples as well, when does the rod go perpendicular? From the middle and titling back away from the puddle? I hold the rod in the puddle, feeding and keep that 15 degree moving from left to right and not changing the angle or direction. I run nice weld most times, but now I'm failing more rather than succeeding more than 50% of the times. Thanks again guys, so happy to have joined and see so many experienced guys out there.

That Miller CST is a high-end unit. Also, while moving slower, be sure your rod is traveling adjacent to the leading edge of the puddle. If you can see molten metal ahead of your rod, then you're probably moving too slow, or your rod angle is not enough. This will swirl the puddle around with adverse results.

If you're welding on clean, freshly ground joints, there is no better rod than the 7018. It burns like butter, lays a beautiful low spatter bead, it's good in all positions, and best of all, it's really-really strong. The 7018AC does not count and will produce less than ideal beads from that Miller DC unit. This rod is designed for those who are stuck with an AC only machine. If that's all you can find, then try it out, it may be better than the 6013.

The 6013 rod, in my opinion, is an artist's type rod. It produces pretty beads but lacks in strength due to its shallow penetrating characteristics. I have used it with a great deal of success on wrought iron when my MIG unit went down on me. It definitely has its applications, but where strength is concerned, it ranks low, and special attention should be given to assure adequate penetration. Like, add 15 amps.

I was told yesterday that the Miller was an AC but after some research and your comments I am now more informed. So the 7018 is different to 7018 A C?
So I am welding from left to right and leaning 15 degrees towards my right, correct?
Also what is the best way to weld vertical and which rod please.?

kseeroo wrote:I was told yesterday that the Miller was an AC but after some research and your comments I am now more informed....

Since your original description said, "Miller Arc/Tig CST 250", it was clear to me without looking up the machine that it is DC capable, because of the TIG function.

If you were not aware that the machine can do DC, this casts your questions in a whole new light. Are you aware of the differences between AC, DCEP, and DCEN? Are you aware of how to set your machine to do each function?

It is entirely possible the troubles you are having (particularly when you tried 6010) are related to your machine set up, particularly if you are accustomed to a simpler machine.

Steve S

I'm sorry if it sounded dumb. I am not a professional welder but has welded with AC machines all the time. I thought I would buy a nice one this time since my old one had a damaged transformer.
Miller is a US brand and resource is limited to us when information is required - That is why I contacted your forum. I understand the concept of DCEP and DCEN a bit. -ve is straight and + is reversed and it is mentioned as well on the electrode box. Basically I try both on new rods and stick to the setting that works the best after reading it. But I will take your comment on board and do some more reading.

Didn't sound dumb at all, and no offense was meant...

I just re-read your original post, and realized this machine is new to you, and you're still sorting it all out.

Steve S

kseeroo wrote:I was told yesterday that the Miller was an AC but after some research and your comments I am now more informed. So the 7018 is different to 7018 A C?
So I am welding from left to right and leaning 15 degrees towards my right, correct?
Also what is the best way to weld vertical and which rod please.?

Yes, from left to right, you lean toward the right so the puddle pours out of the rod like a yummy cake frosting and splashes up making little waves, aka the bead. Watch the puddle and make sure it's penetrating along the outside edges. Stay cool, you're in control, no need to get excited or hurry. With a new rod, don't be afraid to steady it with your left hand, it will tell when it's too hot to continue to touch it.

Vertical requires less rod angle, move uphill, keep moving, too slow will wash away, practice. Work it with 7018, 6013, and 6010, they're all a little different.

Notice the process control section of your manual. http://www.millerwelds.com/service/loca ... t_name=CST 250 VRD INTERNATIONAL This is referring to arc force and provides some basic guidelines for various electrode uses. See the table is section 4-2 of the manual.

If you have any questions please just ask. All of us love this stuff and like to help whenever possible.

Nils

Thank you all for such great advices. So lucky to have you "mates" as we call it here around. Will try these settings and will revert.