In the story "Welding with Children" the first point made is that the man has four daughters who have four children, one each. They are not married.
The next point made is that the man, their grandfather, is babysitting the children and a third point is that the two men in the town refer to the grandfather's car as a bastard mobile because the man drives around his grandchildren who are legally bastards because they were born out of wedlock.
The main characters are the grandfather, the children ,and the two men in town.
The theme is somewhat hard to figure out. The man loves his grandchildren and is a good grandfather. He spends time with them, but hopes he can get his children to do a better job than he did in raising them.
The two men in the town identify the fact that the men's daughters had children with out being married has made him fail as a father.
Since the issue of the father's failure to get his daughters to grow up right, I would say that the conflict is the father having to deal with the outcome of his children's decisions.
Another theme is the father's guilt at not being a better parent to his daughters. He tried to make it up through his grandchildren. However, he is really a good grandfather and father because he helps his daughters with their children.
I ask my students to look at the title --- "Welding with Children" --- and notice what it's saying --- welding with children is dangerous. Could it be that the way the grandfather raised his children, and the way the children are raising his grandchildren, is dangerous to their well being? They are endangered physically, emotionally, and spiritually by the way they are being brought up. For example, the motor hanging from the tree lays them out, they are emotionally hurt by the abandonment of their fathers (and grandmother) and they are not being taught moral and spiritual values which endangers their souls.