Cutting open a rattly muffler

My '83 Standard Specification, Mondial QV's stainless steel muffler has a nasty internal rattle. Others have commented that they too have experienced this problem. I guess an internal weld has broken. I want to keep this muffler if I can repair it.

Before I cut it open to (hopefully) affect repairs, I ask: Have any of you experienced this problem and solved it by any method other than replacement?

 

Thanks. I can certainly get it open. Finding the broken weld (or whatever) is another task all together. Superformance offers a beautiful replacement for pretty resonable money BUT, I don't want to put any more money into this car if I can help it. My Mondial QV is not the love of my life. Well, neither is my 308GTB but it's a close second after my wife Nancy.

I bought the Mondial because I had owned it before and it is a known quantity to me. The friend I bought it from needed the money to keep his fledgling company afloat. So I bought the car and gave up the 0.65% interest at the bank. With 20/20 hindsight, the car is a much safer deal! Of course, its also a blast to drive and its beautiful! Those facts didn't make it any easier to say, "No thanks."

So the logic is that I want to make the car function as nicely as possible without investing much more money. The new 16" wheels and tires pretty much tapped out my budget. Anything more and I'm into it upside down. Therefore, I cut.