Acoustic Guitar Bellying

[greeny]

Not having owned a new Acoustic guitar before my current one (bought last November) I'm trying to figure out what is normal and whether I have a problem or not.

The action on my guitar has raisied slightly from around 2.2mm at the 12th Fret Low E (6/64). To around 3 mm now (8/64). The action on the high e is not noticably different at around 2 mm (5/64). If I put a straight edge accross the guitar behind the bridge I can see there is an arch. I'm not sure how much of an arch existed when new and it's not such that you would notice anything untoward. All I am really noticing is the higher action.I have checked the neck relief and the nut and these seem fine.

I found this info on a Martin Site (my guitar is not a Martin):

The bellying of the top is normal and should be expected. The top is actually made with an arch. This will increase over a period of time due to string stress and/or high humidity. Heavy-gauge strings should not be used. If the bellying becomes excessive, the saddle and bridge may need to be lowered to improve the playability.


So What is normal.? Would you expect a slight bellying in the first year of life? Should it settle down after this? SHould I takeitback to the shop and ask themto sort it? Should I just get a Luther to file down the Saddle and not worry about it?

[Dave Orban]

Yeah, it's fairly normal. Should settle down.

The saddle can be filed down, but I'd wait a bit first. How stable is humidity in your area?

[greeny]

I'm in the UK, so we don't really get extreams of humidity, we are usually in the 40-60% range.

The guitar did spend an afternoon in a hot car boot recently (in it's case) but other that that temperature and humidity shouldnothave been too much of an issue.

[jpfeiff]

I'm in the UK, so we don't really get extreams of humidity, we are usually in the 40-60% range.

The guitar did spend an afternoon in a hot car boot recently (in it's case) but other that that temperature and humidity shouldnothave been too much of an issue.

While the bellying doesn't sound too extreme, keep that thing out of a hot car "boot" (whatever that is??) Yes, one afternoon baking in a hot car is enough to majorly mess with the healthj and well-being of your guitar...

[greeny]

"boot" (whatever that is??)

I guess that would be the trunk for the Americans out there.

[Whiskeyrebel]

Time to call the Bridge Doctor.

[OlAndrew]

Take a good metal straightedge, lay it lengthwise on the frets, and run it down near the bridge. See where the end points. If its at the top of the saddle, great, if its at the bottom of the saddle, not so great, if it points into the wood of the bridge, you've got a real problem.

Check out th JLD Bridge Doctor. I've used it on a couple of my guitars with GREAT results, there was a thread about it awhile back. Many luthiers are recommending them now, as an alternative to a neck reset, and some feel its a better idea.

Hot car boots are real Bozo No-No. The glue used to hold guitars together is softened by heat. Great, if you want to work on it, but terribly destructive if its strung up to pitch in the heat.

Good luck!

[prsisbest]

Funny, I'm going through this exact same thing right now. I dropped mine off with my local tech yesterday to get this taken care of.

[greeny]

Take a good metal straightedge, lay it lengthwise on the frets, and run it down near the bridge. See where the end points. If its at the top of the saddle, great, if its at the bottom of the saddle, not so great, if it points into the wood of the bridge, you've got a real problem.


Not quite sure I fully understand this:

If the straight edge comes to the top of the saddle then that means your strings are going to lay flush on you frets -i.e unplayable.

If the straight edge comes to the bottom of the saddle then this may be about right depending on how high the saddle is. My saddle is approx 4mm, with an action of around 1mm at the first fret and 3mm at the 12th fret then extrapolating to the bridge you would expect around 5mm there. And using a straight edge unsuprisingly that comes around 1mm below the top of the bridge (ie 5mm from the strings).

Is this really a big problem? Could I just not take around 1mm off the saddle to bring the action down?

[Stubee]

Guitar tops belly, at least every Gibson and most Martins I've owned did. Gibson used to design an arch into the top when bracing to help keep things stable. I figure they still do.

It sounds pretty normal to me, but if you are really concerned, could have a tech check the braces to make sure nothing let loose there when hot in your boot. I'd doubt it, but could put your mind at ease.

Guitars also change a bit thru the seasons with temp & humidity. Might just be seeing a bit of that.

[greeny]

I changed the strings a couple of nights ago and had a fertle around inside while the strings were off. There's nothing loose, or buzzing, or rattling. I guess I'll just get a bit filed off the saddlle to improved the action slightly.