It is possible to blast too deep, but it would take a long time to blast so deep that it makes the object look funny. Now, if you’re just doing lettering or some sort of announcement, the rule of thumb is to not blast half as deep as the line is wide. Anytime the sandcarving etches deeper than the width of any line, the etch becomes a V-shape cut, making the personalization harder to read.
It’s important to try and maintain as close to a 90-degree angle as possible when sandcarving. However, it is only natural as you pass up and down that the angle will change slightly.
Here’s a tip when etching large negative areas: if you work the design and text areas of the stencil a little bit extra, it gives an overall impression that the blast is actually deeper than it is.
—Billy Willis, Rayzist