If you’re just getting started with a laser cutter, you may be wondering what materials to buy. There are so many to choose from, it’s bewildering, and if you aren’t careful, you’ll spend a fortune. I’ve tried more different materials than I can remember and I’ve narrowed it down to what I think are the best three to begin with.
I’m assuming you want to do something more interesting with the laser cutter than engrave names and photographs on chopping boards. If that’s what you want to do, that’s fine, and I doubt you will be needing my help.
If you want to stretch a little to see how creative you can get, read on for my three top materials.
I’m assuming you have access to a typical school, college and small workshop cutter. Perhaps the machine takes sheets up to 600x400mm and the laser is 50W or so. Some (like mine) claim to be 85W which is an exaggeration. The lower power cutters of 35W or less may only be useful for engraving, lacking the power to cut anything thicker than cardboard.
MDF is cheap, stable, and the sheets will be flat if they are stored properly (which won’t be the case for plywood). MDF is available in a range of thicknesses. I think 4mm is the best choice. I found 3mm a bit too thin for finished products to have enough “heft” to them. Thicker MDF will ask a lot of your cutter unless you have serious power available.
MDF isn’t pretty. For purely functional items like jigs, that’s fine. For more decorative items, MDF can be painted. I have had excellent results using clay paint protected with furniture wax.
Wherever possible, buy laser quality MDF.
4mm birch ply
Birch ply has beautiful grain which is enhanced by polishing with furniture wax, Danish oil, Osmo Polyx or something similar. The ply is more difficult to work with than MDF as the sheets probably won’t be flat, even if thay are stored carefully. I cut 4mm birch ply on a special jig I made to hold if flat in the cutter. An easier ‘though less successful strategy is to tape the ply down to the cutter’s honeycomb bed. When making something like a box, choose the area of ply for the lid carefully. Find the area of the sheet which is flattest and has the most beautiful grain.
I have found 4mm ply works well for boxes up to 20cm wide. For larger boxes, I use 6mm poplar.
3mm birch ply is also available. As with 3mm MDF, I find this too thin for anything but the smallest projects. Thicker birch ply such as 5mm and 6mm is usually significantly more expensive than 4mm, and often difficult to source. I use 5mm birch ply to make hinges for 6mm poplar ply boxes as it is much stronger. My cutter can barely handle 6mm and I haven’t had good results. 5mm birch ply is usually more expensive than 6mm. Strange but true.
Laser quality ply is essential as it is made with a clean burning glue. Conventional ply will have blackened, sooty edges after cutting.
6mm poplar ply
Poplar ply isn’t as strong as birch, yet it is plenty strong enough for a large jewellery box. It doesn’t have the beautiful grain of birch. It stains very well. I have found the sheets to be flatter than 4mm birch and easier to work with. I don’t bother with my cutting jig for poplar, I lay the sheets on the cutter’s honeycomb bed.
You probably won’t need any more power to cut 6mm poplar than you need for 4mm birch.
For the light stain in this box, I mixed a small amount of purple stain with Osmo Polix oil. Used neat, the stain is very strong and dark.