If you’ve never done this before…. practice first!
My research shows two fundamentay different methods of installing frets. You can either press them in or hammer them in.
Fret pressing equipment is probably out of the question for any one-time/first-time builders. However, it is something I will consider if/when I build additional guitars. My only experience is hammering frets in, so this is all I can speak to.
Again, if you’ve never done them before, practice. Use a scrap piece of wood and buy extra fret wire. Based on personal experience, this will alleviate frustration and improve the final quality of your guitar, reducing the need for fret leveling and dressing.
I found the keys to success being many light taps and a firm base under the neck. While vendors want to sell you a brass faced dead-blow hammer, I found that a smooth faced carpenters hammer works fine. If you are tapping and not “hammering”, I found no evidence of marks or indentations.
Ideally, your fret wire needs to be pre-formed to a radii that is smaller than the radius of your fret board. If so, the outer edge of the wire will sit in the fret slots while the center rises above the board.
Your first strikes should be on the outer edges to begin, and only begin seating the wire. Your first strikes should not result in the outer edge of the fret wire being fully seated! Once the wire is securely started you can begin lightly tapping the wire working from the outside to the center. Slowly work your way back and forth. As the center of the fret wire is lodged deeper in the fret board the outer edges will have a tendency to pop up some. If they come out completely, you are driving the center in too fast.
Starting at the edges, then working from the center out you should see the tang of the fret wire gradually sink into the slot as the wire slowly takes on the same radius of the fret board.
To make sure I had a secure base, I cut 15 inches from an old pair of jeans. I enlisted my wife to sew up one end, filling the sack with about 8lbs of fine playground sand. After sewing the other end, I had a sandbag that would easily support the neck of the guitar while easily forming to the shape necessary.
