Why does my sandcarving sometimes go through the mask?
This can happen when the nozzle is held in one position too long. This will cause the mask to heat up and soften, reducing its capabilities as a resist. A second possible cause is contamination in the grit. Contaminants act like a “dart,” piercing the mask and causing a pinhole effect. A third possible cause is the use of abrasive media that is too coarse. Photoresists are most effective when used with grit of a 180 mesh size or finer.