Why wont my Turbo and Downpipe stop leaking?

[antnicuk]

I cant seem to stop the V band join on the back of the turbo from leaking!  it seems a lot of people use them and dont have a problem.  Do they have flexible downpipes or anything similar to stop the vibrations.  My down pipe bolts to my middle silencer which is all bolted to the gearbox.  It seals reasonably well when i first tighten up the clamp but after a few miles it starts leaking.

Is there any alternative to the v band clamp,  i am thinking of welding a 3 or 4 bolt flange to the back of the turbo and the same to the down pipe!

Any ideas cos this is driving me mad :mad: