welcome to well . com I'm Bob Moffatt welding instructor with Cowley College
welcome to weld. com I'm Bob Moffatt welding instructor with Cowley College
I actually want to try to walk the cup downhill on a root pass and finish the
subsequent passes uphill
this is a kind of a procedure that would follow over in the pipe as well so i
have plates
30 degree bevel I want to fit these with about a 5 30 seconds to three sixteenths
gap and I want to run a downhill root today
I know there's some argument about whether you run uphill downhill which
one's stronger
I want to show you that this is a it's it's a good process we've used this a
lot in the piping industry especially on rolling pipe where we're using a flux
core process to filling cap
it's in a it's approved procedure we've tested this and it's it's strong
so I want to get some gear on I want to attack these plates up and run this
downhill root for you
I want to show you how easy this is I want to start this I'm gonna I'm gonna
hold this i'm pointing this up I'm gonna come off of my tack up here at the top
of the plate my wire is pointing up hill about 30 degrees after i get going for
about a half inch or so I'm actually going to take my right hand away and run
this one-handed and I'm gonna walk the cup downhill
I'm just sliding this along and I want my wire to stay on the leading edge of
the weld pool
always if I outrun this and I shoot the wire through a dead air space and I
don't have
a park anymore ok so let's start out up here at the top
so when I started this world from backing up i did make a slight change in
voltage and amperage simply because i was going to have a slightly longer
stick out
I was real confident with the gap and as you can see you just gonna walk in this
down and gently going back and forth on the leading edge just to make it to make
the web
full progress you know this i'm not saying anyone's thoughts too long
again i'm running this one-handed
yeah
full penetration with just the right amount of reinforcement
I ran the root on this downhill I've already buff the glass and slag out of
the inside with a flat wire wheel
I want to put a Phil pass and a cap
except now i'm going uphill never i never want to
well downhill in a groove there's too much chance of lack of fusion the minute
ago when we did the route we had our wire pointing up hill about 30 degrees
and i stayed on the leading edge to get my fusion and control the backside
now i want to point my wire straight in or slightly downhill believe it or not
that's the biggest problem that I see with a lot of students and amateurs is
the point there wire uphill to go uphill
okay you need to think about getting that wire driving it into clean material
down inside the groove so that you're getting the proper fusion
also if you point your wire uphill
if you've ever seen anybody do this you will see a lot of spatter buckshot bebes
coming off the front edge
okay that's that's not fun your machine actually runs nice and crisp and clean
if you're pointing it straight in
ok there's a there's another little subtle technique that i really want to
discuss here and it's i'm filling this groove up you're going to ask me what
well how do you weave
do you just go straight across well the answer is yes and no if I have a lot to
fill up then I want to build a little shelf down here my filler metal
I want to bring the wire up into the center go across to the edge and then
come straight across
it's like a lazy triangle ok and the total movement of my wire up is probably
an eight to three sixteenths of an inch
tops now pause on the sides i want to pause on the sides of this bevel face
and I want to watch that tie in
the center of it will take care of itself
my whole philosophy and doing groove welds is I wanted to be flat
I want to be able to clean it whatever past that I put in after that I want it
to be flat so that I'm not welding over the top of a big hump
ok so I'm going to start down here at the bottom
yeah
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since i'm going to do this well in three passes and I'm pulling this wire up in
the center and refilling the center and leaving to the outside about not
probably 3 30 seconds seven inch - my bevel dead again i want to leave my
beveled edges alone because they're my guide when I go to my cap straight edges
i want to run a stray cat
turn the feet the studying Electrical stick out
simple repeatable motion
yeah
via a buff this out and i'm getting ready to put the last pass in here I
wanted to talk briefly about the objectives of of what we're getting
ready to do here
no undercut we don't want undercut on the edge of the bevel on the edge of the
group face and I don't want my reinforcements on my beat height to
exceed an eighth of an inch
that's pretty simple I've left myself enough room to run this last pass in
here naturally and again it's it's the exact same motion and the exact same
wire angle
I want to . this in and go uphill with it
yeah
the motion i'm using now is simply a i guess you could call it a lazy oval not
really going up that much
I don't need to I am staying on the leading edge of my weld pooll and I'm watching my
edges to make sure that they're using into the plate
Little pause there
One thousand and one... One thousand and one
we finished this welld here and we've left the subsequent passess alone again we
ran a root pass down hill in this groove
we ran a fill pass up hill and we stopped up here so that we could see it
and then we ran the cap or last pass
there's a couple things to note here I don't have any undercut on the sides and
a lot of my glass and and deposits were in the center of the bead here and
you'll also notice that the ripple pattern is more
it's it's pretty smooth and they're fairly scrunched together
I like that I as it is if somebody that was an inspector that would look at a
well I don't like the great big cat paw look on the on the MIG welds
they're kind of cool and you get to the tick but with a MIG I like this because
i know this glass is floating to the top we're not trapping it into the bead
so again no undercut and we buffed this off it should look pretty clean
thanks for watching
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