i want to learn to weld...

[GHarman]

Arc Blow and back stepping

Good explaination Coalsmoke! I would like to add that Arc Blow can occur from leads that are coiled together, purposely or in advertantly. It can also come from rod that has a deteriorated coating condition called fingernailing. where the rod coating flakes off the rod above your nice arc and then the arc moves up the rod on the side of the coating damage. This condition will challenge your rod manipulation skills to the max.



Back stepping can also include a serious skip between beads on a larger piece that requires a weld from A to B. Example; A left handed application,





A2<<<<1,8<<<<7,12<<<<11,6<<<<5,10<<<<9,14<<<<13,4<<<<3B



This keeps the Heat Affected Zone (HAZ) more or less, parallel and minimizes distortion on the X-Y axis. The Z (thickness) axis may require chill blocks.





Undercut on a horizontal tee can be minimized by placing your rod more parallel with the vertical member, slightly angled back toward the direction of travel and dragging the edge of the rod along at the desired toe of the weld on the vertical member. This allows for deposit at the toe with less arc force directed into the vertical member, preventing digging and negative effects gravity working on the molten puddle. GregH

 

[THenningsen]

Greg-I've set my machine to 90 amps and it seems to do better. I am noticing little holes in the weld bead, what I think is porosity. What is causing this? Am I moving too fast? I'll try to post a picture on here if I can figure it out.

 

[THenningsen]

here are a few crappy beads i've run. you all tell me what I can improve on.



Cummins Page



thanks.

 

[GHarman]

THenningsen, What rod and what polarity? If you are running 7018, you are going to fast and it looks like you have to long of an arc. You need to shorten up your arc length (maintain the end of the rod closer to the puddle as it is consumed) and move slower. You should try heating that rod in an oven for a few hours also. The areas where the chill rings are < shaped is an indication of excessive speed, the spatter and porosity are long arc and possible moisture in the rod coating. Are you grinding your base metal or are you welding over mill scale? GregH

 

[THenningsen]

Greg, it's 7018 and DCEP. And no, I haven't been grinding... just going over the mill scale. Guess I shouldn't do that with 7018 huh. As far as my arc length... should i have it down almost touching the puddle? I was trying to maintain an arc lenght equal to the thickness of the rod.

 

[rbattelle]

Greg, it's 7018 and DCEP. And no, I haven't been grinding... just going over the mill scale. Guess I shouldn't do that with 7018 huh. As far as my arc length... should i have it down almost touching the puddle? I was trying to maintain an arc lenght equal to the thickness of the rod.

I've found things work a lot better without the mill scale.



I've found the shorter the arc length, the better (short of sticking it to the work). So I tend to really get in there. The book I was referring to earlier (by Brumbaugh) says that whereas a short arc won't guarantee a good weld, a long arc almost always guarantees a bad weld.



Ryan

 

[THenningsen]

good advice... . i'll try that. Thanks guys. The trick is to force myself to slow down. I thought I was really going slow, but I guess not.

 

[GHarman]

THenningsen, Let me throw a little extra into this equation. #1 make a line on your plate with a scribe after you have removed the mill scale. #2 You can make punch marks every 1/2" or so to help you see your line. #3 Start your arc 1" away from the actual starting point and bring the arc back to the start and begin the weld. Progress left to right, using your right hand or right to left using the left hand. You are in effect, dragging the rod. #4 If you have your heat set right, you should be able to drag the rod with the coating touching the leading edge of the puddle, allowing the puddle to fill in behind the rod as you progress.



Another method is to use an oscillation with the rod, parallel to the line you are following. This is a "preheat-deposit,preheat-deposit,preheat-deposit" repetition pausing at each deposit point and not oscillating the rod along the line more than "three times the rod diameter". Remember, you are NOT making the weld wider (weaving), you are progressing the length of the line you have scribed and punched. You will be able to see the molten metal flow and fill at each pause.



Once you have mastered the technique of a straight bead with parallel sides, try interlocking beads that lap over each other by 1/3 their width and cover your plate. GregH

 

[GHarman]

Hey, Safety Reminder

Oo. When you are grinding, dont forget to wear proper PPE!. 1. Dust mask/Respirator. 2. Safety Glasses/Face Shield. 3. Ear protection. 4. Dont use your hands as hammers at any time! You and your family will thank me in 40 years!! Protect yourself while enjoying your hobby/occupation. If you dont, no one else will and the price you pay down the road aint worth it! Have fun!Oo. GregH

 

[rbattelle]

4. Dont use your hands as hammers at any time!

Why? Arthritis?



I love the smell of the gases released from stick welding... but I still wear a respirator.



Ryan

 

[GHarman]

Osteo Arthritis, deformitys and joint inflamations that can arise over the years of doing this kind of "adjustments". What do you think is going to deteriorate first? A hunk of iron or your finely tuned hands, wrists, fingers? (Tarsals, Meta tarsals and Phlanges) GregH

 

[THenningsen]

I know the answers will vary on this but, what is a good size rod for just practicing? I'm not welding any projects, just running beads right now. I had some 3/32 rod, is that a general use size rod or would I be more apt to use 1/8"?

 

[rbattelle]

I do most of my learnin' on 3/32 rod. Less likely to stick than 1/8" rod, cheaper, and I can use it on thinner scrap.

I've only done 1 project where I needed to go to 1/8" rod - a mobile chassis for a machine tool out of 2x4x0. 12" structural steel. I probably could've used 3/32, but tried 1/8" instead.

Ryan

 

[GHarman]

If you have been using 3/32" rod there is no reason to change until you get your beads the way you want them. 1/8" rod in 6010 will use the same heat range as 3/32" 7018 but dont confuse the characteristics. They run completely different. 7018 is slow freeze low hydrogen rod that has medium penetration. 6010 is a deep digging, high penetration, fast freeze rod. 1/8" 7018 will run about 20Amps hotter than 3/32" and you will carry a larger puddle. GregH

 

[DValentine]

I would disagree on the idea that 3/32 will stick less than 1/8th rod. The bigger the rod the more amps you will run. I ran a bunch of 5/32 and 7/32 7018 for a job, and then had a heck of a time running 3/32 afterward. If you are sticking the rod then the amperage is too low or the rod is not being started right.
If I may offer a thought, why don't you try and run a really slow bead... . way too slow and watch the puddle spread out. Watch what is going on. Get away from trying to make the correct bead. Then run too fast. Again watch the puddle. It will be thin. Try the extremes then find the "happy place".


Dave

 

[rbattelle]

I would disagree on the idea that 3/32 will stick less than 1/8th rod. The bigger the rod the more amps you will run.

Sorry about that, Dave. I was thinking that if you run 3/32 on, say, a 3/16" thick piece of steel at 60 amp, it's less likely to stick than a 1/8" rod on the same piece of steel at the same amperage (increasing amperage on that thin metal would risk burn through with the 1/8" rod).



You're right, of course. Given the proper electrode and current selection for the piece of metal at hand, no rod is particularly more likely to stick than any other.



Ryan

 

[DValentine]

Sure, Ryan, rod size selection is based on, in part, to the thickness of metal.

 

[THenningsen]

where do you all buy rods? I went to Lowes to buy some practice rods but their 7018 we AC rods. Seems like I would pay a premium at airgas or the like.

 

[OKish]

i get all my rod at a weld shop. i would recommend getting 3/32 7014 rod for practice.

 

[GHarman]

Hey Bud, You are gonna pay a premium if you buy in small quantitys of any commodity. Go to all the suppliers online and get suggested retail prices. Then visit the place that is closest to you with the best prices, open an account and negotiate price on your rods. We have many suppliers around here, including Great Western Airgas, General Air, US Welding, and Buckeye Welding Supply ( I have an account here). I use the latter as they will beat the others by a mile on prices on consumables. I never buy consumables at Home Deficit, Lowe Downs or SNEARS. They do not carry what I need. Yes, welding rod is expensive. If you buy a 50# can, you can negotiate the best price per pound on that rod and you will have a guarenteed source of consistant practice rod for a while. When I was learning welding in school, years ago a 50# can of rod went pretty quick! I realize you are on a tight budget, I am no stranger to that situation, myself. Sometimes the welding shop will give you a bargian here and there on broken can lots of rod if they see your smiling face often enough and realize you are a potential long term customer ( student weldor). Just some thoughts. GregH