6 inch ducting ok for a 4 inch carbon filter?

Hey RIU, well here goes this story bear with. I bought a 4 inch carbon filter along with a 4 inch fan. However the light I want is a 6 inch air cooled hood, and I already bought the 6 inch inline fan for it. Do I have to buy another 6 inch carbon filter, or can I rig 6 inch ducting to a 4 inch carbon filter? Is there any sound way to do that?

It all depends on the cfm of filter.. If air is moved too fast thru it then it doesn't have time to scrub air clean.

Yea it will work as long as the CFM isnt to much through the filter. Use one of these here: http://www.advancedgreenergysolutions.com/product/4530.35?www.advancedgreenergysolutions.com

Its a 4" to 6" increaser for ducting. This will allow you to just hook the fan and filter up through 4" ducting, the right before it hits the light, put the increaser on it so the 4 inch ducting will fit over the 6" intake. Good luck

ok to answer your question yes you can dude, you just need to buy a 6in to 4in flange

lowes or home depot sells reducers, 6" to 4".

I do this exact same thing... 4 inch carbon filter, rated at 200 CFM with a 6" to 4" reducer attached to 6 inch ducting and I use an exhaust blower rated at 180 CFM... Its the CFM ratings that you should go by in trying to figure out if your air-moving equipment is compatible with each other... You want the fan/exhaust CFM to be lower than the CFM rating on your carbon filter.