Started getting finish checking on 20 yr old J-45?

[gustophersmob]

Howdy!

I have a 1996 J-45 that I bought new in 1998. Up until a couple years ago I had kept it in its Gibson hard case and used a Gibson clay pot humidifier in the winter (I live in Ohio).

Then two years ago, I took my guitar to my luthier to get some frets replaced and a general setup. He pointed out that the guitar needed additional humidification, so I got a humitar sound hole humidifier and a caliber IV hygrometer. Unfortunately, that struggled to keep the guitar humidified, so based on a lot of reading on here, I got a Hiscox case to help it stay humid (and better protected in general). That did the trick, and I've been able to keep it at a near constant humidity year round.

However, the very first winter with that setup, I opened the case one day and noticed some finish checking on the top in the treble and bass lower bout. This was the first bit of finish checking even though it had spent 20 years without adequate humidification. Then this winter I've noticed a bunch more checking all over the top and back.

Now, I don't really mind the checking, it's kind of par for the course with older Gibsons. I'm mainly more concerned about why it's happening now. It seems like I'm doing things "right"," but they're not working out so well.

Thoughts?

[Don54]

My understanding is that finish checking generally occurs as a result of a sudden change in temperature. The finish expands or contracts at a different rate than wood causing the finish checking.

It wouldn't bother me either. Especially on an old guitar. I have an old Martin and love the finish checking on it.

[gustophersmob]

Thanks. Thats kind of what I was thinking, except I assumed that the new case and more consistent humidifying would minimize that expansion and contraction.

As long as I'm not doing something that can damage it, I'm OK with the checking.

[Wade Hampton]

The other day I was reading an article about forgers who fake old paintings, and one of the things that they have to get right is the “craquelure” that occurs in the varnish over the surface of these paintings. It was the first time I can recall encountering that word, so I looked it up. It’s exactly what I suspected once I saw it: “a network of fine cracks in the varnish on paintings and furniture.”

So what we on the forum have been calling “finish checking” and “windowpane crackling” has an impressive and official French name: “craquelure.” You can drop that in conversation with the next pretentious person who annoys you, and watch them scramble to convince you that they know exactly what you’re talking about!

Seriously, though, sometimes you can do everything humanly possible to prevent finish checking on a nitrocellulose lacquer finish, and it occurs anyway. Nitrocellulose is a fairly unstable chemical compound that shrinks and degrades over time. It continues to shrink and off-gas its plasticizer chemicals as time passes, and it doesn’t require any mistreatment to do so. It’s just unstable stuff that’s basically evaporating in slow motion, regardless of what you do.

So I can understand your chagrin, but unless you’ve been taking the guitar into a 200 degree Fahrenheit sauna with you, then dashing out and rolling naked in a snowbank while still strumming “Knocking On Heaven’s Door,” it’s really not your fault. Sometimes craquelure occurs simply because THAT batch of lacquer is in more of a hurry to shrink than the lacquer on your other guitars might be.

Hope that makes sense.


Wade Hampton Miller

[1Charlie]

Perhaps it is the other way around.

As a guitar ages, it gets drier and drier. And smaller and smaller, which the lacquer can’t do. Thus the cracks.

Just a theory.

[Wade Hampton]

The wood of the guitar can and will expand and contract with humidity changes, and that can sometimes show in some minor finish damage. But what’s usually called “finish checking” (craquelure) is a result of the finish shrinking and off-gassing.


whm

[ManyMartinMan]

Pretty standard fare for a J-45. All don't but most do.

[gustophersmob]

Thanks for all the responses!

I'm not concerned about the crazing from an aesthetic standpoint, I just wanted to make sure the sudden onset wasn't anything to be worried about. Especially considering its seeming correlation with my new case and attempts at humidification.

It sounds like the group wisdom is that everything is OK.

[zombywoof]

Originally Posted by Wade Hampton

The other day I was reading an article about forgers who fake old paintings, and one of the things that they have to get right is the “craquelure” that occurs in the varnish over the surface of these paintings. It was the first time I can recall encountering that word, so I looked it up. It’s exactly what I suspected once I saw it: “a network of fine cracks in the varnish on paintings and furniture.”

I once had the finish restored on a 1942 Gibson. The luthier wanted the finish to "catch up" with the rest of the guitar so it did not stick out like a sore thumb. I am obviously not sure what solvents, plasticizers and such were in the nitro but he sprayed it on in a very thin coat. In about 9 months I started to see the crazing appear and in another three you would not have known the finish was not 75 years old.

[J Patrick]

...to further the conversation...I have an early 60”s Gibson that has significant craquelure...(thx for the groovy new term Wade)...on the top but the back and sides show none at all...i’ve had Gibson’s from the 40’s and 50’s that displayed the same thing....oddly enough the headstock faceplates almost always have the finish checking too...that suggests to me that the checking has much to do with top movement in the case of the soundboards...that could be humidity issues or it could be just the result of playing the guitar...i can’t figure why the headstock faceplates crinkle up...

[Monsoon1]

Originally Posted by Wade Hampton

The other day I was reading an article about forgers who fake old paintings, and one of the things that they have to get right is the “craquelure” that occurs in the varnish over the surface of these paintings. It was the first time I can recall encountering that word, so I looked it up. It’s exactly what I suspected once I saw it: “a network of fine cracks in the varnish on paintings and furniture.”

So what we on the forum have been calling “finish checking” and “windowpane crackling” has an impressive and official French name: “craquelure.” You can drop that in conversation with the next pretentious person who annoys you, and watch them scramble to convince you that they know exactly what you’re talking about!

Seriously, though, sometimes you can do everything humanly possible to prevent finish checking on a nitrocellulose lacquer finish, and it occurs anyway. Nitrocellulose is a fairly unstable chemical compound that shrinks and degrades over time. It continues to shrink and off-gas its plasticizer chemicals as time passes, and it doesn’t require any mistreatment to do so. It’s just unstable stuff that’s basically evaporating in slow motion, regardless of what you do.

So I can understand your chagrin, but unless you’ve been taking the guitar into a 200 degree Fahrenheit sauna with you, then dashing out and rolling naked in a snowbank while still strumming “Knocking On Heaven’s Door,” it’s really not your fault. Sometimes craquelure occurs simply because THAT batch of lacquer is in more of a hurry to shrink than the lacquer on your other guitars might be.

Hope that makes sense.


Wade Hampton Miller

I gather then that it would be complimentary to tell a forger "your oeuvre has craquelure".

[zhunter]

Someday you'll get to this level of craquelure...maybe.

hunter

[docwatsonfan]

So I can understand your chagrin, but unless you’ve been taking the guitar into a 200 degree Fahrenheit sauna with you, then dashing out and rolling naked in a snowbank while still strumming “Knocking On Heaven’s Door,” it’s really not your fault. Sometimes craquelure occurs simply because THAT batch of lacquer is in more of a hurry to shrink than the lacquer on your other guitars might be.

Hope that makes sense.


Wade Hampton Miller

now that craquelled me up

[Photojeep]

Originally Posted by Wade Hampton

...

So I can understand your chagrin, but unless you’ve been taking the guitar into a 200 degree Fahrenheit sauna with you, then dashing out and rolling naked in a snowbank while still strumming “Knocking On Heaven’s Door,” it’s really not your fault. Sometimes craquelure occurs simply because THAT batch of lacquer is in more of a hurry to shrink than the lacquer on your other guitars might be.

Hope that makes sense.


Wade Hampton Miller

You are a treasure Wade!

PJ