How do you attach ducts anyway?

[!!!]

I've noticed there's no real thread on how to attach ventilation ducts and pieces together. I just see everyone using duct tape.

If I have a fan with a 6" diameter inlet, and a 6" diameter duct, how do I attach the duct to the fan? I can't just put the duct in and use a clamp because the 6" diameter inlet on the fan tapers from 5.5" to 7" - and so the clamped duct easily slides out. Duct tape would work in this example, but how is the fan supposed to be used?

 

[keeper]

i put duct tape around the edges of everything this helps the worm clamps to have something to "bite" into
then i cover the clamp with duct tape as well

 

[the Rock]

shoot some self tapping screwss thru the clamp and duct then tape the crap out of it

 

[geopolitical]

Sheet metal screws & duct mastic.

 

[ItsAllOver]

Screw/Mastic is key for permanent installations, but I just use a worm-gear clamp, then a wrap of duct tape. It has always worked for my temporary applications. If I ever have a proper grow room set up, I'm going screwed and mastic all the way.

 

[AKDrifter]

Mine are all the flexible expanding aluminum type ducting and I just use the aluminum tape. Quick and easy. One day I guess I may have a permanent set up that will never need to be moved, then rigid/smooth ducting would be the ticket for better efficiency and such.

 

[Vincent Vega]

Personally I prefer to use tuck tape (sheething tape, not duct tape) then a clamp. IMO the adhesive in regular duct tape gets dry and brittle when cold air is being blown and too gooey when very hot air is being blown.

 

[EvilTwin]

Mine are all the flexible expanding aluminum type ducting and I just use the aluminum tape. Quick and easy. One day I guess I may have a permanent set up that will never need to be moved, then rigid/smooth ducting would be the ticket for better efficiency and such.

I also find that the aluminum tape works great. It's strong and conforms well. Good adhesive. Duct tape tends to dry and lose adhesion after a year or so. It also works great for blocking small light leaks. More expensive but worth every penny.
ET

 

[B. Self Reliant]

I've never trie aluminum tape, so i can't speak for that. However, if you use duct tape, get the name brand good stuff. If you try to save a few bucks by getting the generic stuff, it comes undone very easily. YOu can wrap it all you want, but if it doesn;t stick, it doesn't matter! I had a bunch of it come loose in an old grow room. The inlet on the window box came untaped and the inake was blowing about 500 cfms directly on plants instead of directing it appropriately. The most expensive $2 I ever saved.