Laser cut coaster of Lake Mendota

This was a christmas gift for my friends this year. Feel free to remix and share your versions!

Material: 3mm birch plywood
Coaster diameter: 3.5 inches

- As always, test on scrap plywood first! Each machine's laser setting is different.
- Preset the three colors for cutting, etching, and engraving

(optional: apply polyurethane coat)
- After cutting, sand it down (also helps remove burn marks)
- Apply 2-3 layers of polyurethane coating for waterproofing

Source: http://www.openstr