I own a pellet stove that has a heat exchanger with extra long cast iron “fingers” (see photo). This needs to be cleaned regularly. The challenge is, a standard brush attachment's bristles are too short to do this properly. This vacuum attachment solves that problem. It fits a Loveless ash vacuum but should also fit other ash vacuums as the hose size is pretty standard. Print this in PETG for strength.

The resulting print is designed to accept a length of bristles cut from a CNC dust shoe brush with 70 - 100mm bristles (choose whatever you need). One of those is enough to make several brushes. I used a small amount of urethane glue to attach the bristles (mist lightly with water first).