Weather Checking

Here's a good example of checking on a 59 335 (note the long guard). Checking can go in any direction but frequently its found everywhere like on this example from Tom H's site

You know when you are thinking about going outside and it looks really cold out there and you want to know how to dress so you go to the internet and punch in Well, that isn’t the type of weather checking I’m talking about.  What I want to talk about is when your vintage guitar goes from one extreme-like hot-to another, say, cold. I assume you’re with me so far. These old guitars are clear coated with nitrocellulose lacquer rather than the polyurethane that is often used today to make a hard clear finish-like the one on your floors. The great advantage of poly is that it stays relatively elastic so when it encounters big changes in temperature, it expands and contracts so it doesn’t crack. But poly makes for a less than ideal finish for a guitar because it changes the way the wood responds to sound waves. There are those who believe that nitro does that too but not to the same extent. Most folks believe that nitro is

Checking can show up anywhere on a guitar, sometimes at stress points like the neck join but sometimes in places that get no stress at all.

better for musical instruments but it has its drawbacks. One is that the Federal Government doesn’t like paints that give off a large amount of ozone layer depleting fumes. Back in 1958, nobody worried about that. Nitro is still used but the formulation has changed so that its less harmful to the environment. Just an aside-it has nothing to do with weather checking. Another aspect of nitro is that it sinks into the wood as it dries and allows it to resonate nicely. It also gets very, very hard the longer it cures. It also gets brittle and that’s where the problem lies. Normally, when you go from hot to cold, things contract. When you go from cold to hot, they expand. You learned that in high school physics but you probably forgot. When you carry your guitar from Eric’s house to Jimi’s house to jam and it’s 15 degrees outside and when you get to Jimi’s, he’s got the heat turned up to 75, your guitar is going to react. Conventional wisdom says that you should leave your guitar in the case and let it “acclimate”. That will usually keep the guitar from checking. But not always. Checking is cracking. As the guitar contracts (gets smaller) in the cold, so does the finish. When it gets hot, the guitar and the finish expand. The problem is that they don’t expand and contract at the same rate. If the guitar expands faster than the finish, then the finish will crack or check. When the guitar contracts from the cold at a different rate from the guitar, it can also crack. The key to keeping this from happening is making sure the changes in temperature aren’t too abrupt. So leaving your guitar in the case when you come in from the cold allows it to change its size more gradually which also allows the finish to change its size more gradually, thus keeping it from checking. It interesting how some guitars check and others don’t. I’ll give you a real life example. I picked up a beautiful red 1959 ES-345 that had been played nearly its entire life by its only owner. He made sure he took good care of it and kept it at a constant temperature where possible so even though the guitar was played almost daily for most of 50 years, the guitar never checked. I also recently drove that long, long I-80 corridor from New York to Indiana to pick up a 1961 ES 335 that had been stored in its case, unplayed, for 48 years. Even though that guitar was in its case the whole time, it was in a closet that wasn’t

This is a pretty extreme example where not only has the finish checked but dirt, grime and player sweat have found their way into the cracks. This rarely happens since checking usually doesn't cause an open crack in the finish. Normally you can't even feel them if you run your finger across the them because the crack doesn't go to the surface of the finish. This is one of my all time favorite 345's from

heated in the winter or cooled in the summer and it must have 1,000 vertical checks in the finish. Even though the virtually unplayed guitar is otherwise mint, it’s still weather checked. The lesson here? Store your guitar carefully and transport it carefully if you want that nice finish to stay as nice as it was when it left the factory. Finally, what does checking do to the value of a vintage guitar? Surprisingly, not much. Collectors actually seem to like a bit of checking. It gives it its aged look, I guess. But, I think that if you have 2 near mint guitars and one is unchecked and the other is heavily checked, you can expect to pay a premium for the unchecked one. How much of a premium will really depend on how much you want the unchecked one.

Leave a Reply

Optionally add an image (JPEG only)