" Remove clash of weld lines" does it make sense?

This sounds like some kind of trade jargon. Any how, I can't visualize the situation, and I've worked with enough professional welders that I should have some sort of clue.

I want to say him before you start welding, arrange the weld lines so that they will not clash with each other. Now, in the drawing he submitted to me, i find a clash. So how to say this to him? "here there is a clash. remove it..." or what?

Let's think two plates are welded to each other. Now, manufacturer wants to weld the third plate on the first two. I want to say him proposed location for the the third plate is not correct and he should move it away from the weld lines of the first two plates so that the weld lines don't clash each other. how to say this? " There is a clash. remove it..."

What.

Scribble on the drawing and send it back to him.

I didn't think of that.