Duct Board Question

[Wolfer]

I am doing a microwave install for a buddy. I pulled out the old range vent to put in a new microwave. The vent pipe is just a few inches above the cabinet bottom. The microwave vent is triangle. There is nothing that will convert and bend that short. Will duct board be ok to use for this. It is above the oven.

[ga-hvac-tech]

The major issue here would be cooking grease collecting on the ductboard... which would be a fire hazard if it ignited... or if there was a fire on the range below and the vent caught. Vents for cooking hoods and appliances should ALWAYS be metal.

You may have to 'custom fabricate' a fitting, or cut some of the existing pipe and install a pre-made fitting.

I would NOT use anything other than metal, and I would be careful the joints between fittings do not have any gaps.

[Wolfer]

Thats what I was guessing here. The opening from the microwave to the vent is so close. Ill have a buddy fabricate a metal box that I can just slip in. Safest way. Thanks

[heating_seattle]

never use duct board for anything

[ga-hvac-tech]

For me, ductboard makes good return plenums in non-humid locations (never in a crawl). Easy for an attic when replacing a dedicated horizontal and adding a media filter to the new furnace.

Personally, I never use ductboard after the air filter... just a matter of principle.

[Frosted]

I am doing a microwave install for a buddy. I pulled out the old range vent to put in a new microwave. The vent pipe is just a few inches above the cabinet bottom. The microwave vent is triangle . There is nothing that will convert and bend that short. Will duct board be ok to use for this. It is above the oven.

NO...NO...NO...but looking at other comments you've probably already figured that out.

You say the Microwave vent is "Triangle", did you perhaps mean rectanglular? There are adaptor fittings made to do just about anything needed.

Mike...