It’s a small thing. But signing your work is part of leaving your mark on the world. I’ve tried more than one day to do it, and seen many others. I’ve signed some pieces with a sharpie, which works very well. I’ve seen some commercial branding irons, mostly with block lettering and little images of hand tools. I think they look a little impersonal, though. There’s also a branding iron (even an electric one) made from your signature. They’re pretty expensive, and I don’t do enough volume of work to justify it.
What I’ve settled on for now is simple. I burn my initials into an out of the way place, drill a small 3/4 inch inset next to them, and glue a penny into it minted in the year the project was made.
I’ve been told that it’s a very old tradition, and was originally done as an offering to appease household spirits. It fell out of custom, but was revived when coins started being dated. It became convenient (and cool) way to date your work.
The flocking on the boxes dried enough to be safe to handle after about 48 hours. It’ll still be soft enough that it requires care for a few more days, but it’s tough enough now to pass the boxes along to their new owners.