interesting I always free handed the root and maybe 1 or 2 more passes then walked the cup on out including the cover.
On the typical double bevel pipe between using the right sized cup and stick out you can set it so your cup simply rests on both edges of the bevel during the root and hot pass. Once the joint is to wide to permit this I switch to walking the cup.
If I understand your question right... Yes I personally limit my cup walking bead width to the same as if free handing, in particular the cover pass can end up being several weave beads that are stacked side by side.
yep same here i free hand the bead the bead and (walk) the rest
as a rule of thumb every where i have worked its any thing over 1/2'' is @ least a 2 bead cap
example l- 1''- l would be @ least a 2 bead cap
l l
l l
l
So I sholdn't get any wider than 1/2. Is this per API or ASME? Or a shop standard?
Intersting that you both are saying that you freehand the root and don't cup walk. It seems easier and more consistent to cup walk for me. I think it would be more difficult to cup walk the fill and cap passes.
Another question is that I am so used to using a remote to controll amperage that I can't seem to scratch start without getting a ton of arc strikes in the groove. Also it is difficult to have a short tungsten stickout to scratch start and then have too much electrode that I will dip my tungsten in the puddle or I will have a large torch angle.
its probably just depends on where you work
where i am at anything wider than 1/2'' is a 2 bead cap
among the reasons I don't cup walk the root is because the gap is so small and the angle manipulation is not that great. I lay the cup against both of the walls of the v and wiggle a bit to wet out the sides if needed. Also I feel i can change speed (and therefore penetration) better by freehanding. After about the 2nd or 3rd pass when the cup no longer rests along both edges of the gap. Then I switch to cup walking which makes it a little easier to stay consistent on the fill passes. I generally cup walk on the cap or do a "sliding" technique i was taught once.
I guess I will have to figure out a way to cup walk the fill and cap passes. It just seems like the torch is on a huge a angle because of tungsten stickout which makes the tungsten too close to the weld bead.
Also you it seems unatural to walk the cup and rest the cup on the bead that you just welded, seems like it would be sort of bumpy or just wierd.
Anyways I will have to try to see some more videos and figure it out.
if the tungsten is sticking out too much, giving a very shallow torch angle then you can try recessing the tungsten a bit, or use a cup 1 size bigger.
I only cup walk as I feel it helps with my consistancy in certain positions mainly by the fact that I can weld fairly successfully without seeing the tungsten or arc (if I have to). in regards to walking on top of a bead, there is a tendency to want to fall off or get caught on ripples, but if the bead is consistent and straight it shouldn't be a problem.
honestly though I don't cup walk every piece of pipe, I find free handing to be slightly faster and just as good appearance on "easier" joints and positions.
what size cup are you using on the fill and cap passes? how far is your tungsten sticking out?
with #8 cup i usually have about 3/16" to 1/4" stickout.
I will probably use a #8.
How much amps are you running on a root pass?
I would guess I'm running 80 to 90 amps. I'm using a welding machine at work older than my grandpa.
There are some good suggestions on the forum already. Search for Tig Root and read the post from medicinehawk01.
amps won't always be the same for every root pass. Gap,pipe size, wall thickness, position of weld, and other factors will require you to adjust your heat, move slower or faster, feed wire, ect.
Use your tacks to fine tune your amps.
Keep welding with a view of learning from every pass.
tig welding rule is ya can go as wide as the orafice of your cup
Everybody welds which way makes them comfortable. When walking the cup on your stringer (if a fitter did not make your bevel good) you should consider using a jumbo #12, it will keep you out of the bevel and will cause you to move at an decent speed and flow and if there are any divits on the top of the bevel, it keeps you from getting snagged up in them. Plus, the more gas the better, esp. if your not paying for it. The stringer on pipe when tigging is your longest part, the rest is gravy. Until you get used to walking the cup on the outside of the pipe, switch to a #8 or #10 and let it sit inside the bevel, it will consistantly burn in better. It doesnt make a darn which way you hold that cup, its round regardless and it will walk. The only problem with freehanding stringers, is even if you PUT a stringer in, you way have not burned make those sides and that could cause your film to bust. Keyholing your stringers works good except tubes (haul @$$). As for your cap, depending on how tight you keep your grouping you can 2 pass a cap, but try to keep that cap at 1 pass as much as possible, remember...they shoot the weld, so if your cap is on actual pipe, if there are pits in the pipe, it could possibly become your bad film when the cranked out xray techs shoot your weld.
I usually walk the cup all the way out. Free handing comes in handy when I need it, but for the most part, walking the cup rules. To me, there is no better way of putting down a bead.
I have welded boiler tubes and ofcourse you can only free-hand those because of where they are and being in close proximiny to each other, etc. Many welds in and around boilers have to be free handed. One is not better than the other, but where do you need to use one technique or the other?
Most carbon steel sched-40 requires atleast 3 passes : root, fill & cap.
Most stainless steel sched- 10 reqires only 2 passes : root & cap.
My 2 cents.
Be well,
Hawk
I walk it all the way out. I feel that it gives me more control andthe bead is more uniform. I have done some free hand in tight places but prefer walking. If you're gonna walk it from bead to cap, you'll need a couple different cup sizes depending on the bevel and sch. of pipe. I usually run a 5 for the bead and hotpass then go to a 8 for everything else. As far as how wide, that's usually set by the weld engineers in the WPS. If it aint, a good rule is no more that 4 times rod diameter like stick welding. When you do a 6 or 2-g weld, you'll only go about 1/4 - 3/8" wide on your stringers. Much more than that and the puddle has a tendency to droop towards the bottom pretty good.
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