I like how you cut right through the word "CAUTION" 
Also that looks like JB Weld?
Yeah, it's a two-part epoxy.
The "hole" if you will, results from the proximity of the flyback to that cage. Since the metal is so close, any pinholes result in arcing. Ken Layton recommends trimming back 1/4 inch, I went 1/2. I'd ditch the cage altogether, but there are some transistors mounted on it.
Looks like a legit repair to me. That glue is probably sturdier than the original casing.
Yep, you are correct, sir. I checked it after it had set for 4 hours, and it was solid.
That right there gentlemen is the PBJ frugal repair seal of approval....
I'm not a foolish American with deep pockets and an impulsive behavior. A new flyback would cost me 3x what I paid for the whole monitor. I'll try a posted, tested fix first, and if it doesn't work, THEN I'll spend the $$$.