Guitar Neck Finishes and How Slick They Feel
Posted: Mon Mar 08, 2021 9:19 pm
Neck profiles and widths certainly affect how comfortable a guitar will play but how slick the neck acts is an important part of playability.
The force needed to move two objects across each other causes friction. All materials have their unique amount of drag (coefficient of friction) when rubbed against. This friction (drag) is different depending on what each of the two materials are.
A piece of rubber dragged across a piece of rubber gives a high amount of drag. More pressure also increases the drag.
Interestingly, the surface area does not affect the drag. Big wide tires on a vehicle provide no more traction than skinny ones. This seems entirely counter intuitive but it is true. The amount of friction is only dependent upon the materials and the downward force pushing the two materials together. Wider tires distribute the forces pushing down (the weight of the vehicle) over a larger surface area but if it is double the surface area, it will only be half of the force pushing down per unit area. This gives the same friction. I know somebody is going to say this is false or why would dragsters and other vehicles have such wide tires. The answer to that is that materials need to be able to deal with the horsepower being put down and the need for beefy components to not break when 11,000 HP is channeled to the rims and tires.
So what does this have to do with guitar necks? The same rules apply. There is friction between the hand and the neck. A small hand and a large hand will slide equally well for the reasons given above. Changing how hard the grip is on the guitar WILL change how well it slides. Similarly, hands can be wet or dry, smooth or calloused, clean or dirty. All of these factors will have an effect on how they interact with a neck.
The hand is only one of the factors. The other is the neck as the drag is dependent upon BOTH surfaces that are trying to slide past each other. Using the same criteria for the hand, neck drag can be determined by how moist or dry, smooth or rough, clean or dirty the neck is. In addition, there is the actual composition of what the hand is touching on the neck. A urethane will slide different than an acrylic for example, especially when a little moist.
An ideal neck would be very well finished with no bumps or irregularities to hinder a hand sliding across. Similarly, it should be a very hard finish as a rubbery finish would allow micro deformation that the hand would have to ride over causing drag. A neck that has not fully cured will be too grippy to slide easily. This improves as the neck cures and picks up some non sticky contaminations with playing.
An ideal neck would also have a satin finish rather than glossy. Microscopic irregularities in the surface of the neck actually reduce drag by secondary factors like reducing suction between micro air entrapments the create tiny micro vacuum pockets and by reducing transient electrostatic bond formations between the hand and the neck.
In reality, hard maple neck that only was sealed but not coated would be one of the easiest neck to slide around the fretboard with. Once an entire coating is put on, the underwood has little to do with it except if some of its roughness make the surface less uniform on a macroscopic scale.
There are some things that can be done to existing necks. The first is to keep it and your hands clean and dry. Another is to use some kind of friction modifier like waxes, REACTIVE car coatings with teflon or silicones, or even a tiniest bit of soapstone or the like on the hand. Of course the age old trick is to use some fine steel wool or sandpaper but I doubt most people will do that to their guitar even though it would help. A good satin unit it gets polished smooth by the hand is always a good choice.
This post became more complicated than I had planned but I will let others chime in on their successes with keeping the neck slick.
The force needed to move two objects across each other causes friction. All materials have their unique amount of drag (coefficient of friction) when rubbed against. This friction (drag) is different depending on what each of the two materials are.
A piece of rubber dragged across a piece of rubber gives a high amount of drag. More pressure also increases the drag.
Interestingly, the surface area does not affect the drag. Big wide tires on a vehicle provide no more traction than skinny ones. This seems entirely counter intuitive but it is true. The amount of friction is only dependent upon the materials and the downward force pushing the two materials together. Wider tires distribute the forces pushing down (the weight of the vehicle) over a larger surface area but if it is double the surface area, it will only be half of the force pushing down per unit area. This gives the same friction. I know somebody is going to say this is false or why would dragsters and other vehicles have such wide tires. The answer to that is that materials need to be able to deal with the horsepower being put down and the need for beefy components to not break when 11,000 HP is channeled to the rims and tires.
So what does this have to do with guitar necks? The same rules apply. There is friction between the hand and the neck. A small hand and a large hand will slide equally well for the reasons given above. Changing how hard the grip is on the guitar WILL change how well it slides. Similarly, hands can be wet or dry, smooth or calloused, clean or dirty. All of these factors will have an effect on how they interact with a neck.
The hand is only one of the factors. The other is the neck as the drag is dependent upon BOTH surfaces that are trying to slide past each other. Using the same criteria for the hand, neck drag can be determined by how moist or dry, smooth or rough, clean or dirty the neck is. In addition, there is the actual composition of what the hand is touching on the neck. A urethane will slide different than an acrylic for example, especially when a little moist.
An ideal neck would be very well finished with no bumps or irregularities to hinder a hand sliding across. Similarly, it should be a very hard finish as a rubbery finish would allow micro deformation that the hand would have to ride over causing drag. A neck that has not fully cured will be too grippy to slide easily. This improves as the neck cures and picks up some non sticky contaminations with playing.
An ideal neck would also have a satin finish rather than glossy. Microscopic irregularities in the surface of the neck actually reduce drag by secondary factors like reducing suction between micro air entrapments the create tiny micro vacuum pockets and by reducing transient electrostatic bond formations between the hand and the neck.
In reality, hard maple neck that only was sealed but not coated would be one of the easiest neck to slide around the fretboard with. Once an entire coating is put on, the underwood has little to do with it except if some of its roughness make the surface less uniform on a macroscopic scale.
There are some things that can be done to existing necks. The first is to keep it and your hands clean and dry. Another is to use some kind of friction modifier like waxes, REACTIVE car coatings with teflon or silicones, or even a tiniest bit of soapstone or the like on the hand. Of course the age old trick is to use some fine steel wool or sandpaper but I doubt most people will do that to their guitar even though it would help. A good satin unit it gets polished smooth by the hand is always a good choice.
This post became more complicated than I had planned but I will let others chime in on their successes with keeping the neck slick.