Guitar Neck Finishes and How Slick They Feel

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Frank Sanns
Posts: 147
Joined: Sun Oct 21, 2018 5:38 pm
Real Name: Frank Sanns
Location: Pittsburgh

Guitar Neck Finishes and How Slick They Feel

Post: # 3637Post Frank Sanns
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.

Eric Jones
Posts: 108
Joined: Mon Oct 15, 2018 12:05 am

Re: Guitar Neck Finishes and How Slick They Feel

Post: # 3665Post Eric Jones
Sat Mar 13, 2021 12:47 am

Frank,

I can agree with what you’ve written. But playing mostly cowboy chords, with occasional excursions to the dusty part of the fretboard, I’ve never really had trouble with the neck finish.

But I was wondering about the decision to have glossy necks vs. satin neck finishes. Some builders have satin necks while Collings (predominantly) has gloss finished necks. It had to be something Bill thought about and came to a decision in favor of gloss.

Infrequently someone will have “speed neck” on a guitar (finish removed with maybe an oil applied), but this seems more common on mandolins (and violins?). Why is this treatment more common on mandolins than on guitars?

Frank Sanns
Posts: 147
Joined: Sun Oct 21, 2018 5:38 pm
Real Name: Frank Sanns
Location: Pittsburgh

Re: Guitar Neck Finishes and How Slick They Feel

Post: # 3669Post Frank Sanns
Sat Mar 13, 2021 2:21 pm

Eric,

It probably has to do with the number of anchor points and controllability. A violin is anchored between the chin and shoulder. The hand needs to both support the tail end and be the anchor point and still be able to slide freely to fret(?) the notes.

A mandolin can also be a bit finicky to anchor so maybe that is why people opt for a more consistent and lower resistance finish.

Of the bunch, guitars are heavier and give more surface to anchor with so some drag while moving between frets does not dislodge the guitar.

Then there is the friction from how tightly one grabs the neck while fretting and moving up and down the fretboard. I tend to not grip very hard so I am good with all finishes. I have never had a problem except sometimes on an occasional brandy new guitar that the finish is still very new. After that, they are pretty much the same for my playing. With that said, I have spent some time with unfinished necks on a several instruments and I like it. Not enough to scuff up one of my own instruments but the feel of polished wood is a different experience. It seems to be far less dependent upon humidity but I imagine they are more difficult to keep clean.

I wrote the original post people people were commenting on the differences in neck finishes on the standard vs the traditional Collings line. There is science behind it but I am not the effect is big enough to really influence a decision of which guitar to buy but others may have another opinion.

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