Thread: 8g Welding Certificate

Gday old fella
I completed my 8g last semester and i'm now doing my 3e i also have the 7 so from memory make sure you plate edges are square and keep the root run small and right in the corner and move fast either with the christmas tree pattern or a inverted v pattern to keep the root run as small as possible and for the cap move fast across centre and pause a little longer on the sides its all a timing thing, i dont recommend grinding your root run, and i agree the 8g is not that easy, people think its a point and shoot thing but its a lot trickier than that ,its four welds downhand fillet, vertical up, horizontal butt and last but not least the pipe ,and they all have to be pretty close to perfect

thanks caveman

Yeah thats the technique I have been using maybe im just not pausing long enough on the sides on me cap, all the other welds i seem to be able to do alright, It is alot easier to do vertical ups with the stick.

Originally Posted by old_fella

When I run the root pass hot enough to get 100 percent peno the weld is to convex. When I run the cap pass it is also convex even when I am going fast across the centre, .

If the bead is too convex there is too much volume (wire speed) for your travel. Its really important here to have the wire absolutely in tune with the voltage,so there is just enough fill and just enough voltage setting tohave the arc pool at just the right heat. It does take some piddling around with but trust me it pays. Set up some 3mm shhet but at 45 degrees and that should help get you close.

Cut the wire speed back a tad,you may even have to alter your landing. Also if your electrode wire is pointing straight in ,that will tend to pump up the bead shape.

If you think of the hands of the clock with the centre pivot in the axis of the pipe. that is what the position many weld in. Excess wire speed just overfills the molten pool giving you the convex shape.

Hope this helps you

Coming up the pipe it works for me to kick the wire up 5 -10 degrees or so.
Grahame

Sorry if you got the wrong idea but i was talking about the fillet weld, I might of confused you when i said cap pass and thought i was talking about pipe.

The cap on any vertical should always be as "thin" as possible to minimise the convex caused by the sag of metal before it cools. Maybe a touch more pause at the edges and snap from pause to pause.

Possibly a root, fill and cap may be more suitable with 3 small passes keeping flatter than two heavier ones.

Grahame

I found that you have to go across the middle as fast as you can but still keeping the arc burning smoothly. In other words, not too fast or your weld will be a series of stop/starts. Sometimes a smaller wire diameter helps you keep your voltage/amps up and your travel speed high enough to skip across the middle pretty fast.

By the way I just re read your post and noticed you said that the root is also convex. You will almost never get a flat cap if your root is not flat. So use the same technique i.e. very fast in the middle of the root and a bit wider in the legs if you have to.