F-512 Belly Bulge?

[tomvwash]

I'm sure this question has been raised here before, and still checking for prior posts...Is this normal for a 2021 F-512, in pics? My 6 strings appear to have a similar makeup. Any insight, much appreciated. Thank you,
Tom

 

[chazmo]

Tom, that looks pretty normal to me. Do you have any pictures of the bridge and the treble/bass edges of the bridge (sometimes you can see belly with that). I don't even think that's a belly. The tops are not actually flat, Tom. They're cut to a radius (not sure what it is these days).

 

[tomvwash]

Tom, that looks pretty normal to me. Do you have any pictures of the bridge and the treble/bass edges of the bridge (sometimes you can see belly with that). I don't even think that's a belly. The tops are not actually flat, Tom. They're cut to a radius (not sure what it is these days).

That's a relief to hear. Thank you very much for that insight. I appreciate it.

 

[chazmo]

One good trick regarding belly is to also look between the soundhole and bridge and see if the top is caving (rather than bellying). If you see some of that, then you might have a problem.

 

[wileypickett]

A good way to see if the belly is being caused by string pull or is part of the design of the top is to also check with your straight-edge with the strings off (or slackened so there's no pull on the bridge). If the belly decreases noticeaby with no string pull, you may have a problem.

In addition to checking the bulge across the lower bout, as you did, also check with your straight-edge laid across the top (above the bridge) from the endpin area to the front -- parallel to the neck in other words. As Chaz notes, If the top is higher behind the bridge and lower in front of it (around the soundhole area), you may have a problem.

If either of these things appear to be happening, I'd have the guitar checked by a pro.

 

[adorshki]

That's a relief to hear. Thank you very much for that insight. I appreciate it.

Just to pile on, "looks normal to me too". Just like your 6-ers.

 

[tomvwash]

Thank you for the insight, all. This guitar is fine, should be for a 2021!

 

[Rayk]

Tom, that looks pretty normal to me. Do you have any pictures of the bridge and the treble/bass edges of the bridge (sometimes you can see belly with that). I don't even think that's a belly. The tops are not actually flat, Tom. They're cut to a radius (not sure what it is these days).

When did Guild incorporate radius tops ? I was unaware of this .

 

[chazmo]

Ray,

The jig they had in New Hartford where they glued the braces onto the soundboards used a vacuum compressor (think shrink wrap) to basically pull down the soundboard into the mold and let the braces glue on perfectly.

I'm not sure if they actually cut the wood with a radius or this was the stage that created the radius. I suspect a little of both?? Anyway, so the tops coming out of New Hartford were all radiused, I think. I can't speak for prior to that, Ray, but I'm fairly sure this has been the case for a long time. That's one of the reasons that fretboards have a radius too.

Anyway, not sure when it started, but was definitely in place in New Hartford. Fairly certain that my Tacoma instruments have radiused soundboards too.

 

[kostask]

Most acoustic steel string guitars don't have truly flat soundboards. Usually, there is a radius of 20'-30', most tending towards 24'-36'. This is done for strength reasons.The braces are made to fit this top radius. Backs are also radiused, but with a lower radius than the top usually. There are lots of variations in this aspect of steel string guitars.

Radiusing is done for structural reasons, specifically to resist string pull. Arguments could be made for increasing or decreasing soundboard raduises on the basis of sound quality, but that is something for another time.

 

[The Guilds of Grot]

Ray,

The jig they had in New Hartford where they glued the braces onto the soundboards used a vacuum compressor (think shrink wrap) to basically pull down the soundboard into the mold and let the braces glue on perfectly.

I'm not sure if they actually cut the wood with a radius or this was the stage that created the radius. I suspect a little of both?? Anyway, so the tops coming out of New Hartford were all radiused, I think. I can't speak for prior to that, Ray, but I'm fairly sure this has been the case for a long time. That's one of the reasons that fretboards have a radius too.

Anyway, not sure when it started, but was definitely in place in New Hartford. Fairly certain that my Tacoma instruments have radiused soundboards too.

The Top Sanding Disks were radiused. For some reason I remember 22' but I wouldn't put any money on it. While we're discussing it, the Backs are radiused also.

 

[Rayk]

Ray,

The jig they had in New Hartford where they glued the braces onto the soundboards used a vacuum compressor (think shrink wrap) to basically pull down the soundboard into the mold and let the braces glue on perfectly.

I'm not sure if they actually cut the wood with a radius or this was the stage that created the radius. I suspect a little of both?? Anyway, so the tops coming out of New Hartford were all radiused, I think. I can't speak for prior to that, Ray, but I'm fairly sure this has been the case for a long time. That's one of the reasons that fretboards have a radius too.

Anyway, not sure when it started, but was definitely in place in New Hartford. Fairly certain that my Tacoma instruments have radiused soundboards too.

Ok thanks got info . I’ll check my F212 you got me curios. . lol

 

[adorshki]

Ok thanks got info . I’ll check my F212 you got me curios. . lol

It'll be different that NH's, they changed top radii there. Suspect it was to accommodate the medium strings spec.

 

[Rayk]

It'll be different that NH's, they changed top radii there. Suspect it was to accommodate the medium strings spec.

Can’t say for strings but radius tops offer stronger top’s allowing for lighter builds it also raises the tops pitch or brightness . Flat tops have a more warmer tone then radius tops . Radius offers more player comfort but I never noticed that side of it . Lol

The radius would also be multi directional obviously or maybe not obviously wasn’t in my case at one time . The center of which I can’t say is a fixed point would be more towards the back end of the top towards the tail block but again can’t say that’s a given . So from what Chazmo says Guild was a bit different if I interpreted right . Lol

But just because the top is humped behind the bridge does not mean it’s a radius top rather just normal flexing due to string tension .

I know my Blues are flat tops and my Harp seems to be as well . My Wilborn has radius top and back .

When I bought my Eastman e40 something with bourgeois incorporation I thought there was something amiss! I have never seen a guitar with a radius like this and I couldn’t stop looking at it and it was the neck to tail block direction besides the tone not overly impressing me I couldn’t stop thinking something is wrong with this guitar . Lol so back it went . It reminded me of a banana. Lmao

 

[adorshki]

Can’t say for strings but radius tops offer stronger top’s allowing for lighter builds it also raises the tops pitch or brightness . Flat tops have a more warmer tone then radius tops . Radius offers more player comfort but I never noticed that side of it . Lol

The radius would also be multi directional obviously or maybe not obviously wasn’t in my case at one time . The center of which I can’t say is a fixed point would be more towards the back end of the top towards the tail block but again can’t say that’s a given . So from what Chazmo says Guild was a bit different if I interpreted right . Lol

But just because the top is humped behind the bridge does not mean it’s a radius top rather just normal flexing due to string tension .

Top radius is measured across the widest point of the lower bout, not "top to bottom".

ALL "flattops" have a top radius with the exception of First Acts https://www.amazon.com/First-Act-Ac...locphy=9032176&hvtargid=pla-991138216079&th=1
because they feel it aids intonation which is outside of their design philosophy.

I know my Blues are flat tops and my Harp seems to be as well .

Lay a straightedge cross the lower bout as shown in post #1 and tell us what you see. Or maybe it'd be better if you just post a pic.

 

[Rayk]

What do you mean all flat tops have a radius top ? Ok so yes the Guilds have a radius top the 2013 F212xlce and the Tacoma contemporary series are as well . Certainly not something that caught my eye like the Eastman did . I’ll add that the radius on mine are as pronounced as it is in Toms post 1. So they probably changed the radius specs.

My blueridge jumbo 12 string does not have a radius unless you’re looking at the rounded sides . Lol

The radius (front to back ) what I mean is not flat from the neck joint to the tail block the radius affects the whole top and backs along with sides.
Ahhhh … editing ! Lol

This pic might help ? Lol

 

[adorshki]

What do you mean all flat tops have a radius top ? Ok so yes the Guilds have a radius top the 2013 F212xlce and the Tacoma contemporary series are as well . Certainly not something that caught my eye like the Eastman did .

All GOOD flattops have a radius, it's necessary to keep the top from simply caving in.

It's measured on the line I explained which you'll note corresponds to where the "high point" falls on that pic. All those angled lines are irrelevant, they simply serve to demonstrate how the radius is changed as the top becomes narrower across the upper bout.

My blueridge jumbo 12 string does not have a radius unless you’re looking at the rounded sides . Lol

It does, it's just very flat. The radius is actually determined at the design stage, it's a segment of an arc, and the the radius of the circle the arc would make if complete, is the top radius. It happens that top radius is centered on the line across the widest part of the lower bout.

The radius (front to back ) what I mean is not flat from the neck joint to the tail block the radius affects the whole top not just a spot .

Technically that "profile" is simply that, a profile, it has nothing to do with topradius, except ot would change on different body shapes and sizes.

This pic might help ? Lol

This article might help?:
https://umgf.com/flat-tops-vs-arched-bracing-t2802-s20.html

 

[Rayk]

Only thing I can say is Saga says the guitar is a flat top non radius’d lol let me read the article. Builder Kevin Ryan say he builds non radius topped guitars which is mentioned in a thread on AGF . Being an 10 yr old thread he may have changed his ways . Lol

I’m not disagreeing with you just interested in the in’s and outs of it all .

 

[kostask]

All quality acoustic guitars have a radiused top, as stated above. Even if you go to a guitar shop, take a brand new, just out of the box decent, or better, quality guitar, the top will have a curve to it (i.e. radius). If you were to take all of the strings off, the top will still have a curve to it. So will the back. It is the way acoustic steel string guitars are made.

I cannot say anything for or against Saga guitars, as I have never seen one in person, nor heard one. But I would sincerely doubt that they are completely flat topped guitars, as measured with a straight edge laid across the lower bout. There are so many problems induced by a completely flat top that it makes it almost impossible to create a structurally stable steel string guitar. Not that it can't be done if you want to go out of your way to do it; with enough top thickness and heavy enough bracing, you can do anyting you want, but it won't be anything anybody would want to listen to.

 

[midnightright]

Ask the Expert: What Happens When Your Flattop Loses Its Flat Top?

To work efficiently, a guitar top must be built lightly enough to vibrate in complex ways.

acousticguitar.com