[RCWelds]

Just trying to clarify terms, as I'm in welding school, and want to understand exactly the correct and common use of the term "root pass." My welding instructor tells me that we will be burning 7018 almost exclusively during the 5 weeks we're focused on stick, before we go on to MIG, then TIG.

Does root pass indicate the issue of a gap of certain size, thus requiring a rod, such as 6011 or 6010 before the filler and cap passes of the 7018? I've seen some say one can use a 7018 root pass, and then go all the way to finish with the same rod. What defines the correct selection of rod........is it the gap between the pieces of a joint [such as 1/4" or 5/16"] ? Or...

Is it the disposition rate of the rod, suited to wide gaps, [flow of the molten metal] thus making it a better choice? I hope I get some great answers to this question....much appreciated!

[Jack Ryan]

Just trying to clarify terms, as I'm in welding school, and want to understand exactly the correct and common use of the term "root pass." My welding instructor tells me that we will be burning 7018 almost exclusively during the 5 weeks we're focused on stick, before we go on to MIG, then TIG.

Personally, I would avoid common usage terms (slang) except perhaps in general conversation as those terms are undefined and the meaning often changes from district to district. If you are formally describing a weld or its preparation, use defined terms from (for example) AWS A3.0.

Does root pass indicate the issue of a gap of certain size, thus requiring a rod, such as 6011 or 6010 before the filler and cap passes of the 7018? I've seen some say one can use a 7018 root pass, and then go all the way to finish with the same rod. What defines the correct selection of rod........is it the gap between the pieces of a joint [such as 1/4" or 5/16"] ? Or...

No, "root pass" does not imply any particular form of weld preparation. From A3.0:

root pass. A weld pass made to produce a root bead.

root bead. A weld bead extending into or including part or all of the joint root.

joint root. The portion of a joint to be welded where the members approach closest to each other. In cross section, the joint root may be either a point, a line, or an area

Is it the disposition rate of the rod, suited to wide gaps, [flow of the molten metal] thus making it a better choice? I hope I get some great answers to this question....much appreciated!

The electrode used for the root pass is often 6010 and the basis of the selection is, very often, habit or because that's what everyone uses. There are some good reasons for using it though including:

• It gives good penetration

• It is quite active and so can deal with some rust, paint etc

• It is fast freeze so it is less likely to "fall through"

It does require some expertise and not all welding machines support it.

I've started the ball rolling but I'm not a welder so I'm sure there will be more input.

Jack

[Gdarc21]

Hi Rc, mate a 7018 is a low hyd stick. It is easier to get peno with a 6010 cause thats what those sticks are made for. If you can do a good job with 7018s all other sticks take way less practise. Your teacher is setting you up for success straight up. Thats great. Enjoy trade school, its a place where you can ask questions and fuck it up in a non consequence environment. I for one suggest playing with settings and making lots mistakes in this environment.
All sticks are different and even brand to brand, sure they have standards per designation but you will find brands differ.
A root run is the first run, so it is the run that gets peno and burns in to both parent metals, how you set yourself up for success is by gap, root face and access to joint techniques and Im sure your instructor will explain it. Getting good peno consistently with stick is tricky at first but when you nail it mig and tig seem easier, imho.
It is crucial to relax and enjoy your trade school years make friends with collegues and teachers, trust me it pays dividends every day after. Welcome to the industry Rc.
Lincoln miller and esab all have good guides on everything welding too.

[RCWelds]

Thanks Gdarc21 & Jack for your posts. Very helpful info from you both! I’m in US, and even though I’m new to welding, only less than a year, and now in school, I’m retirement age, but not trying to get myself out of work, but get myself into the kind of work that I want to do!

[Gdarc21]

Thats cool, what sort of work are you hoping to do and what sort are you retiring from?

[RCWelds]

Thats cool, what sort of work are you hoping to do and what sort are you retiring from?

Not retiring yet, may work for a couple more years until I'm 70. Looking to do repair work on trailers, etc, and perhaps some farm equipment, and some light fabrication/welding. I'm even toying with the idea of converting one of my trailers into a mobil rig for on site service. I like to build things, and I've already invested in most everything I would need, but would like to possibly pick up a good used engine driven unit like the Miller Bobcat 260, if I could locate one. I presently have a Miller Multi-process unit, and a larger generator which would likely do 90% of what I would need. I also have a plasma cutter, assortment of saws, grinders, clamps, mag drill, etc,etc...

[LAB80]

Just trying to clarify terms, as I'm in welding school, and want to understand exactly the correct and common use of the term "root pass." My welding instructor tells me that we will be burning 7018 almost exclusively during the 5 weeks we're focused on stick, before we go on to MIG, then TIG.

Does root pass indicate the issue of a gap of certain size, thus requiring a rod, such as 6011 or 6010 before the filler and cap passes of the 7018? I've seen some say one can use a 7018 root pass, and then go all the way to finish with the same rod. What defines the correct selection of rod........is it the gap between the pieces of a joint [such as 1/4" or 5/16"] ? Or...

Is it the disposition rate of the rod, suited to wide gaps, [flow of the molten metal] thus making it a better choice? I hope I get some great answers to this question....much appreciated!

If you have been watching lots of videos on the youtubes, american vidoes, they use a lot of 6010 / 6011 for root passes... Especially on pipe.

I am a newbie at welding, got my first job lined up doing welding in a week. But, the basic guts as far as I understand it is, they use 6010/6011 to weld in a 'layer' in the gap. 6010/6011 is very good at filling in gaps when set to the right amperage, and the fit up is consistent. You can use it up hill, down hill, in whatever position you want. If you have ever spent a lot of time dicking around with 6010, you will find its very versatile, aggressive in terms of penetration, and fun to use.... But it is also very brittle and 'weak' in comparison to 7018. So basically the use 6010 to put a weld in there, they grind it out to make it nice and clean, and then generally use 7018 to weld over top, which provides the actual strength to the weld.

There is another electrode which is used a lot more commonly in AU and NZ; 7016, or 16TC. It is like a 7018 except it has less flux coating, and is a lot easier than a 7018 to do root welds with because the puddle is less fluid so you can control it more, and you can run it at a lot lower amperage than a 7018 of the same diameter, so it does not blow through and chew holes in the metal.

If you can do good root welds with 7018 you should have no issues doing anything else though, as its probably among the trickiest electrode types to do root welds with.

Take this all with a grain of salt, as I am still a newbie but that's my understanding of it.