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I am starting to brace the top for my purplr heart build and I would appreciate some suggestions from the been there done thats

The upper bout is 11-1/2" the lower bout 15" the length is 20" and the final thickness will be 4-3/4"

I have braced the back with 5/16" x 5/8" Braces as you can see .

The top bracing started as the same size materials. The X is glued in and the Brace at the neck Block is Glued in . Everything else is just fitted . I can shave down the x brace with no problem . However I guess what Im asking is , Given the size of the guitar " Small jumbo ? " How thin do I really wanna go with the top bracing .

And what kind of sound will I be looking for Because of the size ? Deeper , baratone ?

I am sure there are a multitude of things to take into consideration here , and I probably wont be able to answer 10% of the questions . So Please Guide me a little b4 I Glue this up . Thanks

Ohh Also btw , this has a 15 ft Radius on the back and top. Dont know if that matters so much , just thought id mention it.

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

I'm working on my 2nd and 3rd OLF MJ's, which are close to the dimensions
of your guitar. I'm using 5/16 x 5/8 X-braces, and 1/4 x 1/2 tone bars and
finger braces. At this point, all the braces look heavy to me. Using the 5/16
width for the minor bracing won't be a problem as long as you're planning on
tapering the minor braces vertical sections as you shape them. That will remove
most of the extra bulk. I also taper the X-braces vertical sections. You should
cap the X-brace intersection, to stiffen up the brace that is cut from the top (the
left to right brace in your picture). Also, your tone bars are shown running to the
opposite X-brace relative to most guitar designs. See the pic below.

_________________
Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

Thanx for the info . Exactly what Im looking for . I laid these out based on a acrylic template , after reading your post I wnt back and checked the template , there is NO "this side up" mark , Did I Have my Template upside down maybe ?


At this point changing the direction is easy .

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Hi Jim,


Is this a left handed build? Just asking based on your tone bars.

Brent

No its right handed build , so yes I guess I had my template layed out wrong side up . I am soooooooo glad I asked this question . Thanks guys !

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

The other thing I thought of commenting on, is that a 15 foot radius is smaller
than that "normally" used on tops. Most people use around 25' for the top, and
15' for the back. There is nothing inherently "wrong" in using the 15' on the top,
but that smaller radius will also help stiffen the top. I'm not suggesting you go
to small, weaker braces now because of that- I'd go ahead and shape them until the
top taps/feels/looks right to you. But in the future, if the guitar ends up sounding tight,
you can think about reaching in through the soundhole with a finger plane, and
taking the braces down a little at a time to see if the sound improves. I did this
with my second OM, and it was amazing how much it opened up...

_________________
Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

I can't add anything that wasn't said above, so I'll ask a question. How was that purpleheart to bend? What thickness? Oops, that was two. . .

_________________
Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Yo Jim! If'n you want a fellow noob's thoughts... first thing to my eye is that those braces are all very thick. I'd shave the fingers and tone bars closer to 1/4" width before gluing them down. I also wouldn't have scalloped down the edges of that upper transverse brace so much... at least 1/4" height at linings, preferably more. Big solid cross beam to hold up the neck, not supposed to vibrate. But I looked inside a Gibson once and they taper it to nothing, so I guess it depends on your overall design.

Another thing that bugs me a bit is the big open area below the second tone bar... those tone bar and finger positions are more like what I'd do if I was going to add third ones. For two of each, I prefer them more evenly spaced within their regions. But again, many guitars built with them more like this, so if you're going by a plan then stick to it. Less of an issue the thicker the top, I think.

You could bevel that tail block so it doesn't have such a large footprint on the top's vibrating area.

And yes, the X brace needs a cap, but not until you've got the intersection shaved down to the height you want. Unless it's already there, but it looks a little tall to me, especially with 15' radius, and even more if you're not planning to carve the braces to triangular cross section (although the intersection itself always stays square so the cap is sturdy).

How thick is the plate? How stiff did it feel before bracing? For me, voicing is very touchy feely listeny work, in addition to looking at it.

As for what kind of sound to expect... that's up to you. Lots can change depending on how you carve the braces and graduate the top.

Jim, for that size of a guitar your present dimensions will probably give you a tight sounding guitar0, especially with that 15 foot radius. If you want more bass and a more responsive feel you should follow most of the suggestions that have been given. The taper on the lower legs of the x-brace is good and will help some but everything appears over built. For a guitar that size I like 1/4 x 1/2 x-braces plus a 1/16 cap. You can shave down the lower legs of the x and carve them into more of a triangle and that will help. They can be scalloped in the area next to bridge plate. The tonebars and finger braces should be thinner, lower and shorter. There is no need to take them to the linings but they should be tapered to nothing near the lining ends. Some don't even take the lower legs of the x to the linings. The upper transverse brace looks fine but a little thick.

The 15 foot radius will make getting your neck angle right more difficult and give you a higher dome to deal with for your fretboard extension, but should help with changes in humidity.

Of course if you have a floppy top that is less than .090 and you like to strum, you're probably okay as is.

_________________
Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I don't mean to steel a tread, but what effect on the sound if you brace it backward? Left handed for a right handed guitar?

Probably nothing! Guitars don't really have a bass and treble side, just bass and treble hot spots, and they vary.

_________________
Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I've built 8 guitars, so take my advice from the perspective of someone who's seen this from your perspective not so long ago, and not as an expert.

I'd agree that you can take quite a bit of mass off of those braces. Left as it is, it will almost certainly have a very "tight" sound. Dana Bourgeois has a very interesting article on voicing soundboards on his website, and I find his explanation of the process that he uses to be very coherent and approachable. A google on "Dana Bourgeois voicing" will get you there. Without trying to paraphrase Dana, my take on it is that he scallops braces until he gets a broad range of musical tap tones from the top, when he taps the top at various locations. He's not looking to create any particular tone specifically, but rather a portfolio of tones that seem to him "musical". I've tried to replicate this process, and it works for me. And I just played a Dana Bourgeois guitar this weekend which ranks among the most pleasing steel string guitars I've ever played.

Anyway, that's my two cents.

As for the reversed tone bars on the bottom, I don't think I'd change them if the top is already glued - there are a lot of various bracing schemes out there - there's nothing sacred about following the Martin x-brace slavishly.

I would leave the reversed tone bar bracing also. But as was said they definitely look beefy.

Curious, why do the center line of the back bracing like that?

Thanks for all the suggestions everyone . None of the tone bars are glued down yet , so I have been shaping them and will be working on the x brace tonight .

I put that strip down the center in the back as a joint reinforcing . Experiment i guess .

Bryan , the purple heart is approx .075 thick and bent fairly well on fox bender , i didnt bend it myself but was there when it was bent.

Again thanks everyone for the help !

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

None. There is no treble or bass side on a top.
It is impossible to offer valuable advice on visuals alone. But 4 3/4" seems too deep for a guitar this size, you are beyond the diminishing returns there IMHO. 5/16" braces are a bit massive for a 15" guitar, 9/16" at the x under the cap is more than high enough, you can triangulate your braces everywhere and gain a bit more flexibility and resonance for your plate. Finger braces do not need to be that massive either, little support is needed there. With a 15' radius for the top I hope you plotted your bridge height and corresponding neck angle accordingly. I am surprised by the back bracing, why suppressing the 3rd brace and notching the braces rather than the cross grain strip? You're losing support in 2 key areas of the back…
Finally you could look at top bracings on the UMGF for example (there are libraries of Martin and Gibson bracing pics), or/and luthier's sites you like, to gain insight, inspiration, and what works visually.

_________________
Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Hey Jim
Is this for the Prima shape?

If so... Plane top braces to 1/4" thick, you really only need one finger brace on the sides. Your braces are really heavy.

The uppper transverse brace should be 1/2" thick and no radius (the way I do it)

Follow the other advice given here and you will be fine.

The radius should be 25' or 28' (I use 28') otherwise you will have an issue with neck angle

_________________
John Ressler

That's a normal construction technique but I was wondering more about the little arches on the braces right over the center strip. Typically the braces run flush across the back there and the strip is slotted to accept the brace. So I was just curious why you chose to arch them.

Unless maybe I am seeing the image wrong?

No your seeing it right . On one of my Mandola Builds I did the back the way you mentioned and it had a "noticable " flat spot when it was finished , may have been a fluke , but it was there. So I thought I would try this and see how it worked . So basically a experiment .

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Thanks John , Yes this is the Prima shape , I did bend it a bit farther so it isnt exactly the same as you sent me . The upper transverse brace has very little arch at all. I did that to help with the neck . The 15ft radius starts at the x braces and the finger braces. I have trimmed the bracing down alot and will post anothe pic as soon as I have worked on the X brace .


Thanks for all the feed back everyone

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Thanks Laurent . I appreciate the feedback and suggestions . I dont follow one comment though

Suppressing 3rd brace ?

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

You omitted the third back brace. Looks like you put braces 1, 2, and 4, but left out #3. I dont know what your plans call for, but generally, there are 4 back braces except on some smaller guitars.

_________________
http://www.CostaGuitars.com
PMoMC

Ok I follow now , lol , From the pic it appears that the braces are spaced oddly , its a bit of an illusion .

From this pic you can see they are basically evenly spaced and 4 seemed a bit over kill ( says the guy who makes his Top bracing to big )


Make Sense ? Or should there have been 4 ? And as for plan ? PLANS? What Plans , we dont need no stinkin plans !

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

I have worked on the x brace and tone bars and am at a point where I think it might be ready to glue down , However I would appreciate additional comments . Please , feel free to make suggestions . Am I still to heavy at this juncture ?

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Would An Upper Bout port help any or Am I thinking about this wrong ?

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Looks a lot better but I don't ever scallop the upper portion of the X-Brace. It's probably fine though and I am interested to hear what others say about that.