Hot melt is like hot glue that you may have used at home on certain projects or repairs. The main difference is once hot melt has cooled it remains somewhat sticky and soft. There are three purposes to using hot melt with driver, fairway or hybrid clubheads.
Remove rattles – Sometimes there is a rattle in the clubhead. This is usually caused by a piece of epoxy or metal that has come loose inside the head. Most new clubheads will have a small port in the sole with a rubber plug. The opening is used to inject the hot melt into the head. Once the loose piece meets the hot melt it is permanently attached, and the rattle is gone.
Add weight – Often times you may want to add weight to the clubhead to increase the swing weight of the club. Adding holt melt inside the clubhead is an excellent way to do this without having to cover the club with lead tape or external weights.
Change sound at impact – Another use of hot melt particularly in driver heads is to change the sound at impact. Some driver heads have a tinging, metallic sound at impact. Adding holt melt inside the head provides a deeper, softer sound that some players prefer.
If your club head doesn’t have a small port, I recommend drilling a 1/8-inch hole in the sole to insert the hot melt. The hole can then be covered using a small plug. Hot melt kits will come with the hot melt cartridges, glue gun and plugs.