Kato 308 Cracked dipper. Help and advise please.

[Bucket on wheels]

A friend of mine has this Kato 308 that has cracked along the side of the weld where the dipper bolt goes through.
After gulching with the plasma. I found that the crack goes through both plates. Any thoughts of how to fix this, and make it so strong that it will not crack again. At my disposal, I have a
Hyperterm 45XP. plasma burner. And a reasonably strong mig. welder. with 1.2 mm tube wire
Does the welding joint I've burned out look reasonable or should it be shaped differently ?
and how should I go along welding this backed up ?
Welding in straight strings or pendulum motion
My plan so far is to weld a straight string at the bottom. Then pendulum motion until I have filled up the welding joint.
Then grind the weld flat.
And then weld on a 10 mm plate.
That's a little smaller, at the shape of the original strengthening plate.
Any advice how to perform this is welcome.
So what you're saying V8druid ?
Are my attack on this ?
On the crazy side or the right side ?

I'm not finished gouging on the the right part of the crack.
I stopped gouging when the big dipper bolt pipe reached a temperature of 200 C

A Continuously measured the temp with a infrared temp gauge

 

[Bri963]

Right. Gouge and prep just beyond the end of the crack, another three or four cm. Plenty of heat into the root run, then build up with stringers rather than weaving. Weaving (or as you call it “pendulum”) will increase stress when the weld cools. Allow time for the metal to cool a bit between runs to reduce distortion until the area is filled. Make sure there’s no undercut at the edges of your capping runs l

 

[doobin]

I love plasma gouging for jobs like this

 

[V8Druid]

Right. Gouge and prep just beyond the end of the crack, another three or four cm. Plenty of heat into the root run, then build up with stringers rather than weaving. Weaving (or as you call it “pendulum”) will increase stress when the weld cools. Allow time for the metal to cool a bit between runs to reduce distortion until the area is filled. Make sure there’s no undercut at the edges of your capping runs l

sounds good to me Bri ... think I would take off a reasonable bit more of the original weld on the boss too and come a bit further along the dipper length also ... don't think Frank has found the end of the crack in that direction and certainly not deep enough at that point

 

[Bri963]

sounds good to me Bri ... think I would take off a reasonable bit more of the original weld on the boss too and come a bit further along the dipper length also ... don't think Frank has found the end of the crack in that direction and certainly not deep enough at that point

Good call, Gra. I just had another look at the picture and clocked what you spotted. Prep needs to get right to the bottom of the crack so the weld burns through.

 

[Bri963]

I love plasma gouging for jobs like this

Sometimes a gouging nozzle on oxy acetylene works better, if you’re used to it.