Checking

[handtrix]

This is unclear to me after all these years on how guitars get their checking pattern.

Let's skip on the how, (that's a given) and focus on the why.

When the guitar is stored in a case:

A. Vertically - do the checks happen vertically ? (North/South or Bridge to Headstock)

B. Vertically On Side with handle upwards... ? Is it the same as "C" or horizontal ?

C. Horizontally - or Flat - On it's back or laying front side. Is this East/West checking ?

 

I assume "spider" checking was the extreme (and the worst causing flaking) in that the guitar rapidly changes temperature. (expansion-contraction & humidity )

e.g. Winter/Summer gigging from hot to cold or from Home to venue to back home.

So warm environment to trunk, to gig then back into car where it sits until your ready to leave.

Back home and back on the stand near a radiator or central air vent. Something like that...

 

or...There is loose & tight checking...Does checking follow the grain when it occurs? (Flame to Fiddleback )

 

I am only speaking in terms of solid body electrics but would it be for acoustics as well?

 

(I guess checking happens to furniture too, but not for this example.)

[BobB]

Wood and lacquer expand and contract at different rates when an instrument warms up and cools down. To keep checking to a minimum, always keep the instrument in a room temperature environment. This is true for electric or acoustic instruments which have a nitrocellulose lacquer finish. When storing an acoustic guitar, make sure the relative humidity stays between 40% to 55% to keep the wood from drying and cracking. Controling the environment an electric or acoustic guitar is exposed to will make a great difference in whether you get checking in the finish or not.

[handtrix]

Wood and lacquer expand and contract at different rates when an instrument warms up and cools down. To keep checking to a minimum, always keep the instrument in a room temperature environment. This is true for electric or acoustic instruments which have a nitrocellulose lacquer finish. When storing an acoustic guitar, make sure the relative humidity stays between 40% to 55% to keep the wood from drying and cracking. Controling the environment an electric or acoustic guitar is exposed to will make a great difference in whether you get checking in the finish or not.

Aye BobB, Thanks for the reply my good man ! I do appreciate your knowledgeable input,

and I totally understand your explanation on the "how" as I mention this in my previous post about expansion-contraction & humidity,

but with all due respect....In the topic description explains the Topic question focusing on Vertical vs. Horizontal patterns.

 

 

Let's skip on the how, (that's a given) and focus on the why.

So, if you or anyone could explain this occurrence relevant to why thy checking patterns happen vertically or horizontally when stored that would be awesome.

I will take heed on keeping checking to a minimum and especially on acoustics !

I do flip my case open leaving the guitar in the case as it acclimates to the room before I do a gig. The least I can do.

[j45nick]

 

 

 

So, if you or anyone could explain this occurrence relevant to why thy checking patterns happen vertically or horizontally when stored that would be awesome.

I will take heed on keeping checking to a minimum and especially on acoustics !

I do flip my case open leaving the guitar in the case as it acclimates to the room before I do a gig. The least I can do.

 

I don't think the physical orientation of the instrument when stored has much if anything to do with it. We all know checking is a result of differing rates of expansion and contraction of wood vs. lacquer.

 

Wood expands dramatically more across the grain than along the grain. This means that checking on the body is more likely to run parallel to the grain, as the wood of the body is free to contract and expand with changes in humidity and/or temperature. You'll find most (but not all) checking in acoustics, whether it is the top, back, or sides, running parallel to the grain.

 

Necks are another story. The grain of the neck runs parallel to the longitudinal axis, but the neck is quite small across the grain, so that there is relatively little absolute contraction and expansion in this orientation as humidity and temperature change. In addition, a neck has less exposed surface to absorb humidity than the thin wood of the body of the guitar. However, the tension of the strings constrains the longitudinal expansion of the neck, which can result in an increased bending moment as humidity increases. The result can be lacquer checking across the grain. You may also notice a sharpening of pitch and raising of action as humidity increases.

 

Laminated guitars like semi-hollows--the ES 335, for example--can check in multiple directions. The laminated parts are more stable, and may expand and contract both longitudinally and transversely more uniformly than their solid-wood equivalents. Neck checking should be similar on both electrics and acoustics, although the string tension is generally lower on electrics due to the lighter strings used.

 

Lacquer probably expands and contracts primarily as a function of changes in temperature: wood as a function of humidity, with temperature secondary.