[darren]

Building a bulkhead around the ductwork and was wondering if it would be okay to use 2x2 for top and bottom and plate with 2x4 turned 90 degrees as the studs.

Want to keep the thickness of the bulkhead to a minimum and have a bunch of short 2x4 pieces I would like to use up.

 

[Mingledtrash]

it would depend on how far you are spanning usually ducts are not more than 24 in. at most so you can put a 2x4 member on edge each side of the duct and let the sheet rock span it. giving 1/2 in space between duct and sheetrock.