Question Regarding White Nitrocellulose

[Graphic Autist]

Yesterday I purchased a used 2008 white 67 Reissue Flying V. This is the oldest Gibson I currently own, and also the only one with a white finish. I have three 2014 hi-gloss models, but the finish feels quite different on them as opposed to the 2008 white V. On the 2014s, I can lightly tap the finish with a guitar pick and it will ding it...it's that sensitive. On this white one, it feels like a hard shell. Very hard to ding (not that I'm trying other than a light tap test with a pick.)

 

Does nitro get harder with age, or is there something different about white nitro versus other color nitro? Serial number on the back of the headstock (which is barely visible as it looks like the finish filled in the stamped area quite smoothly) matches the paperwork I received with the guitar. Have I been had? Truss rod looks just like other Gibsons. Just this finish thing has me perplexed.

 

Thanks in advance for reading this rambling post.

[BigKahune]

... Does nitro get harder with age, or is there something different about white nitro versus other color nitro? ...

 

Harder with age - Nitro gets drier with age. Nitro is an evaporative finish, it doesn't cure. It can take a long time to dry completely, and can be "soft" for months. (soft=solvents still evaporating)

 

Color difference - AFAIK no.

 

 

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[zigzag]

It really depends on how the NC is formulated and modified. Nitrocellulose resin dries faster than any other resin I've ever worked with in the sense that it releases solvent very quickly. How fast solvents evaporate from it is determined by the solvent's power to dissolve it and the evaporation rate of the solvents employed. But, nitrocellulose is very hard, and unmodified, it is also very brittle. It can be modified with other resins or plasticizers to make it much less brittle (i.e. flexible) and give it much better abrasion and impact resistance, e.g. polyurethane resin. It can also be modified with resins, like melamine, that "cure" (with high heat, over 250 F) through cross-linking, which also makes nitrocellulose, or any coating, tougher. If it is modified with plasticizers, many of those materials will migrate out of the NC coating making the coating more brittle as it ages.

 

Polymers (or in this case, monomers or oligomers) that are formulated to "cross-link" (like polyesters, urethanes, melamines, acrylics, etc.) used in wood coatings often use UV energy or electron beams to cause the cross-linking (curing) process to occur. Polyester and polyurethane polymers are often formulated to dry without curing (thru solvent evaporation) and still maintain good impact and abrasion resistance.

 

Formulating coatings is an interesting business, and I suspect Gibson (or whoever supplies them lacquer) has dozens of ways that they have formulated their NC finishes. Adding white pigment (usually titanium dioxide) would likely not improve the impact resistance of a coating by itself. Adding an over lacquer on top of the white finish would determine the guitar's handing characteristics, and a clear coating can be formulated in the ways I have described. Understand that guitars are painted first with a pigmented, or dyed, layer (unless there is some type of primer coating). Next they will receive several (or many) layers of clear lacquer or coating.

 

You have indicated that the 2014s will ding with light tapping. I don't know how light the tapping is, but this doesn't sound good. It sounds as if the wood used in the body might be the larger problem. But you must understand that NC, unmodified, has poor impact resistance, and tougher polymeric coatings, like "poly" coatings, tend to be much tougher.