Youngest lad has joined the 2 wheel brigade  on a Honda 125. he's got a small hole in a rear pipe and

a) wants to know if its OK to patch it for forethcoming MOT and if so what is best method. It's a long time since I did any exhaust patches, but my prefered method was Gun Gum and an old tin can ,held with wire  over the hole ,with GunGum sealing and the tin can to stop erosion.

b- if there's any better way  with modern stuff or is this a temporary way to save money( bit tight with him as he's using the bike to hunt jobs and get to a wage packet).

 

As I understand it a visible patch such as you describe (and we all used to use) would be an mot fail, but an invisible repair would not.