Flexible drive wire brush

[Shane Finn]

The titanium exhaust of my Z06 has developed a fatigue crack. I have found some one to weld it with all the right gear but they need the inside of the pipe cleaned of all carbon soot. The point to be welded is about 1.2m from the open end of the cat back.

I figure I need something like a wire brush driven by a flexible shaft about 1.5m long connected to a electric drill.

I have no idea where to start looking to find the bits needed to do this? Any ideas?

All help gratefully received.