Why are checking lines horizontal?

[thisisduncan917]

I don’t know the answer, but why are checking lines horizontal and occasionally vertical? I would expect them to be random like crazy paving if I had never seen them before. Sorry if this sounds like a dumb question. Below is my 1967 Standard.

 

[Decadent Dan]

Path of least resistance?

 

[Colnago]

They run the opposite of grain direction typically. It’s just the way the finish cracks in relation to the expansion and contraction of the wood underneath.

 

[Go Nigel Go]

As Colnago says, it all comes down to expansion and contraction. The amount of expansion or contraction in the finish and the wood can vary depending on the materials, sizes and shapes, and even whether the cause is humidity or temperature related. I have seen finish cracks go with the grain, across the grain, and even craze cracking which goes every which way. It's not just guitars either, the same thing happens with furniture or any other sort of woodwork with a hard finish. Softer finishes, and oil finishes are much less susceptible to cracking.

 

[papagayo]

To obtain this kind of checking you can put your SG in a fridge.

 

[thisisduncan917]

They run the opposite of grain direction typically. It’s just the way the finish cracks in relation to the expansion and contraction of the wood underneath.

Makes perfect sense!