Cold smoker - ducting issues?

[gasbag]

I've been doing some very basic cold smoking for a while now, and I've seen quite a few homemade cold smokers where users connect aluminim ducting to the vent on Weber BBQ kettles.  E.g.:

http://www.mamaliga.com/wp-content/uploads/2010/07/dsc_10651-1024x680.jpg

I'm trying to work out how this sort of ducting can be connected to the BBQ lid without damaging or riveting the lid.  I'd be using the following type of Weber BBQ as the smoke generating chamber:

http://www.weberbbq.com.au/ProductPage.php?pc=k121024

Does anyone have any knowledge or experience with ducting?  Also, is ducting available in very narrow diameters, where it could possibly fit through one of the vent holes?

 

[chilefarmer]

GB, you might check some of the auto parts stores on ducking. I know some smaller sizes were used on different engine applications, and would be able to take the heat. CF

 

[daveomak]

GB, evening....  You could try a muffler shop for smaller pipe.....   Dave

 

[pike2]

    interesting idea