Material(s) for lagging a hot-air duct?

Beenie

We have a warm air heating system. Most of the duct work from the furnace is is flat and can be easily insulated with proprietary material such as Kooltherm Duct Slab, which we have used.

The problem is that we have a circular duct/pipe which bends at all sorts of odd angles and so the flat slabs are not going to work with this shape. What we need is something that can be wrapped around a circular duct with 9" diameter.

Any ideas?

FreeBear

Rockwool do a product specifically for this type of application. It is a layer of rockwool insulation loosely bound to chicken wire. You'll probably find it quite expensive for the small amount you'd require.

I'd suggest glass fibre insulation wrapped around the duct and held in place with chicken wire. Use cable ties to secure the edges of the chicken wire, and it should out live you.