MDF

MDF or Medium Density Fibreboard is a man-made wooden board. It's made in large flat sheets in a variety of thicknesses.

MDF is one of our favourite materials for laser cutting. It's cheap, reliable and gives good sharp results.

Lattice bowl in 3mm MDF

Lattice bowl in 3mm MDF,
painted with car spray paint

Triquetra

Celtic Triquetra symbol, 50mm aross in 3mm MDF, with raster engraving to give a sense of depth at the crossings.

Advantages
Cuts well. The laser gives a neat, clean edge to it. This allows parts to be made to fit accurately together for easy assembly. Even working automata with levers and gearwheels can be made from it.
Paints well. Most paints work with it, from children's paints to household emulsion and car sprays. Just be careful with water-based paint.
Glues well. Woodworking PVA glue or, for small pieces, Superglue.
Cheap!
Disadvantages
It doesn't cope well with water. It's certainly not an outdoor material.
There are moisture resistant grades of MDF that can be suitable for indoor use such as bathrooms. There's also a very waterproof outdoor grade that is useful for signs, but this is only in 9mm and is rather expensive.
Mechanical stiffness. MDF is effectively lots of thin sheets, bonded together. It's strong for loads edgewise, but will bend over time if used as shelving. With the laser, we can construct girder forms that are much stiffer.

Cutting

Various thicknesses of MDF

MDF cut edges in thicknesses of
2mm (top), 3mm, 4mm, 6mm, 9mm.

With the size of our large laser, sheets up to 3 feet × 2 feet can be cut in one piece.

Most of our work is in 3mm or 4mm thick MDF. The thinnest is 2mm and we also use 6mm and 9mm. Above this, it suffers charring problems on the edges – the laser can get through it, but the results aren't neat.


Japanese box lanterns

Japanese box lanterns

These lanterns have frets of 2mm MDF, backed with translucent paper, in a frame of 3mm MDF.


Props for the Test Tube Cabaret show.

This is a cabinet to be used on stage, so it has to be strong. It's 9mm MDF. Normally a carpenter would cut this with a jigsaw. With the laser, it was cut easily, the mortice and tenon joints to hold it together were cut accurately at the same time, and also some precisely positioned screw holes were cut to fit the internal machinery.


Some of the hundreds of working parts, three whole sheets of cutting, to make a Hoberman sphere.


Steampunk Deathstarfish

It might not look like it, but this is still 3mm MDF.


Engraving

Most MDF engraving is line engraving, rather than raster engraving.

Royal Mail letter measuring scales
Painted MDF, line-engraving through the paint for the lettering

MDF can be raster engraved, but it's not usually the best material for this type of engraving.