today, i went to a sanitary-material-shop for professionals. and i got lucky: found some "non perforated worm-drive hose clamps". the ones i already put on, are 12mm wide. the look to solid and massy. these new ones are very sleek and slim!!! 8mm. so i changed them. now i am satisfied with it :-)

Attached Images
Hitzeschutzband_17.03.15_4.JPG (1.24 MB, 174 downloads)
Hitzeschutzband_17.03.15_9.JPG (1.73 MB, 121 downloads)