Try another carving on white medium density fiberboard

Want to be extra careful of the bath panels. They are actually masonite with melamine as a white surface. Good ventilation is necessary as you know already.
BTW: Using a CO2 laser these panels are a real mess when cutting.

• Ethan

  : Stuff I use is only 3mm thick and sold as white faced hardboard/MDF not Masonite. It has a Matt plastic like finish.