How to Cut Acoustic Panels
Cut acoustic panels with the tool that matches the material: an electric carving knife for foam, a serrated insulation knife for fiberglass or mineral wool, and a fine tooth saw plus a utility knife for wood slat panels. Whatever the material, cut against a straightedge.
Tools by material
Foam
Carving knife
Auralex says to use an electric carving knife and a straightedge, and "let the blade do the work."
Mineral wool, fiberglass
Serrated knife
Rockwool recommends a serrated insulation knife for stone wool and calls utility knives "less suitable."
Wood slat
Saw + knife
Primacoustic: a sharp fine tooth saw or oscillating tool across the slats, a utility knife through the felt lengthwise.
Cutting mineral wool or fiberglass
Cut mineral wool and fiberglass by hand on a table, following Rockwool's steps. Garage, not bedroom, if you can.
- Gear up first. Safety glasses with side shields, gloves, long sleeves, and a dust mask, per Rockwool's guide.
- Mark the line with a straightedge and marker on a stable table.
- Press a board or straightedge down along the line and saw through with the serrated knife.
- Vacuum the fibers afterward and wash your hands in cold water.
Got a lot of cuts? Rockwool lists circular, miter, and table saws with carbide-tipped or metal blades, set slightly deeper than the insulation over a sacrificial sheet of MDF or OSB.
Cutting slat panels vertically
To cut a slat panel vertically, slice the felt backing between two slats with a utility knife. No saw needed. Shortening one means sawing across every slat and the felt.
For the frame around the core, see how to make acoustic panels. Core materials: what acoustic panels are made of. Full plan: home studio acoustic treatment guide.
Related questions
Can acoustic panels be cut?
Foam, fiberglass, mineral wool, and slat panels can all be cut to size. A framed, fabric-wrapped panel needs its frame rebuilt and fabric rewrapped after cutting.
Do I need a mask to cut fiberglass?
Yes. The CDC's ATSDR says to wear protective clothing, respiratory protection, and eye protection when installing insulation, because airborne fibers irritate the eyes, nose, throat, and lungs.
More answers: Home recording FAQ