Official Luthiers Forum!
http://www-.luthiersforum.com/forum/

Aarrghh!! I better ask..off centre X brac
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=11304		 Page 1 of 1
Author:  Irwin R [ Fri Mar 16, 2007 12:26 pm ]
Post subject: 

Well My X brace wondered off centre while in the go bar deck...see pics



It seems solid, I profiled it  a bit...( even though it left a smear of glue...)


Any problem just leaving the blasted thing where it is( call it an experiment) or should I remove it and try again...( top has 25 ' radius if that would make a difference)...If removal is recommended, what would be the best way to do that ...whittle it off till I bottom out and reach the top, or can I use heat to get it off( glued with titebond,   or some other way.. ..I humbly await direction .....Thanks...
Author:  gozierdt [ Fri Mar 16, 2007 1:00 pm ]
Post subject: 
If it's not a guitar for a customer, I'd leave it on if it were mine. At least it shifted toward the treble side, which wants more stiffness for the higher frequencies. I've seen so many variations on bracing in the 9 months I've been frequenting luthier forums that I don't think that small a change would make a huge difference.

Or, you could make it a smaller size guitar with an oval soundhole
Author:  Bill Greene [ Fri Mar 16, 2007 2:21 pm ]
Post subject: 
Finally something I have experience with. My first guitar, a kit but with handmade braces, did the same thing in the go-bar deck. It moved probably 1/8th of an inch (if not slightly more).   The builder I was working with said the ssame thing Gene did, which was this:

Make certain the bridge plate will still nestle firmly between the braces, and firmly below the bridge, with the outside wings of the bridge crossing over the braces and with enough room for the string holes to fit reasonably on center. If it does, you're golden...if it don't you'll want to seriously consider taking it off. Mine did, so I left it alone, and it turned out to sound just great.

I think you're probably good to go.
Author:  Rod True [ Fri Mar 16, 2007 4:39 pm ]
Post subject: 
Although it would most likely turn out fine and like Bill mentions, as long as the wings of the bridge will fully straddle the xbrace, you will be fine , personally I would take it off an re-do it simply because that's not what I planned. This is one thing that Paul Woolson has taught me over the past several years of being here on the OLF. Make it right and you won't be tempted when/if something else will be "good enough".
Author:  crazymanmichael [ Fri Mar 16, 2007 4:57 pm ]
Post subject: 
perhaps my eyes are deceiving me, but being a bit off center does not seem to be the only problem. the spread of the x would appear to be exceedingly wide, like about 120*.
it does not look as though a normal 6" steel string bridge might span the lower bout spread at the likely bridge location.
Author:  nickton [ Fri Mar 16, 2007 7:21 pm ]
Post subject: 
You are now the member of an exclusive club. No more comment (except mine sounds fine)...
Author:  Bruce Dickey [ Sat Mar 17, 2007 2:04 am ]
Post subject: 
Try using Charlie's placement template. I copied his methods and it works. Simply line up the plexiglass with the center glue joint and mark through the pertinent points which are drill through. Connect the dots lightly and you can quickly see if it's wandered any. Hoffman does share a bunch of this on his site: www.hoffmanguitars.com





The x means put brace this side of line.

Here is my page with the layout shown
Author:  James Ringelspaugh [ Sat Mar 17, 2007 5:27 am ]
Post subject: 
Whether it's off center a little would be of no concern to me; however, IMO it is absolutely imperative that the x-braces catch the sides of the finished bridge. If they do not cross directly over the bridge, the instrument's tone suffers, and from a structural standpoint the guitar would be much weaker.
Author:  Irwin R [ Sat Mar 17, 2007 8:18 am ]
Post subject: 

Thanks so much's folks.. I took some more pics and I think I'm in trouble...


 



my x brace angles are on the pics, but I put on my bridge blank size and location ....


Here are the plans..


.my bridge blank is not wide enough( only 4 '') to follow thru with the suggested bridge plan shape( 4.4'')..Kinkead book...so in the photo I just cut out of paper my bridge balk size and layed it out....


Thanks for all the help so far...what's the consenses now?


Could the bridge blank be trimmed so it looks sort of like this.... or would the wings be too small?


 


and maybe move it a little towrds the neck and just bump back the saddle location on the bridge the same amount?...oh s*%&...I'm starting to reach for the chisel...help!!...sorry for all the hastle ..but hey..it's still fun...I'll work on something else for a while and see what you say...
Author:  CarltonM [ Sat Mar 17, 2007 4:57 pm ]
Post subject: 
Irwin,

Plans are only suggestions--reasoned ones, but suggestions nonetheless. I don't know if this would work in your case, but you can always make your bridge longer so both wings span the "X". You can also make a bridge plate to whatever size and shape you need.

On the other hand, if this anomaly is going to decrease your excitement for the rest of the project, then take those babys off, start over and rest easy at night!
Author:  af_one [ Sun Mar 18, 2007 1:26 am ]
Post subject: 
I did the same thing--I don't thinyou'll be happy unless you remove them. You can heat them, but I took my SM glue clearing chisel and took them all the way down and then sanded the glue off bith the orbital--worked fine and pretty quick.
Author:  Irwin R [ Sun Mar 18, 2007 3:04 am ]
Post subject: 

Thanks everyone...I think I'll remove them... the bridge predicament is getting the better of me.. ..I'm in no hurry..just a little scared I'll ruin the top...but I'll take my time...and pay closer attention when gluing next time....


 


Cheers
Author:  JJ Donohue [ Sun Mar 18, 2007 3:57 am ]
Post subject: 
I think you made the right decision, Irwin. You just learned a lot more than just the importance of centering your X-Bracing!
Author:  Joe Beaver [ Sun Mar 18, 2007 2:09 pm ]
Post subject: 
Sounds like you got good advice here. Just one more thing.... in the future you might consider glueing the bridge patch in first, then after it dries, the x-braces. That is the way most of the big guys do it. It sure helps to center things and get the x-brace on the right mark.

Just s thought.
Author:  Irwin R [ Mon Mar 19, 2007 2:44 am ]
Post subject: 

Hi Took off the X brace..no problem ..thanks..I probably would have left it on if there wouldn't have been a bridge placement potential problem..but glad I did...


ROOKIE QUESTION..hey why is the X brace joint not glued( or is it and I missed something )..  .. if it isn't.. is it because of the room the glue would use up and perhaps potential shrinkage after drying
Author:  old man [ Mon Mar 19, 2007 2:50 am ]
Post subject: 
Irwin, are you talking about the actual joint between the two x braces? Glued to each other? Mine are glued.

Ron
Author:  Irwin R [ Mon Mar 19, 2007 3:50 am ]
Post subject: 
Yes Ron...Thats what I'm wondering ..unless I missed it In the Kinkead book and the Cumpiano, I don't know if it actually mentions specifically glueing the X brace joint...Maybe it's taken for granted?
Author:  crazymanmichael [ Mon Mar 19, 2007 3:59 am ]
Post subject: 
the joint most emphatically should be glued, as should the joint cap.
Author:  Irwin R [ Mon Mar 19, 2007 4:09 am ]
Post subject: 
Holy Cow!!...Thanks..Glad I asked!!,,now I'm really glad I took the original X brace off...
Author:  CarltonM [ Mon Mar 19, 2007 7:57 am ]
Post subject: 
It's odd, isn't it...every guitar-building instruction book has something missing. Often something important to the beginner, who needs that knowledge the most! There are just so many small details in lutherie that it's difficult for authors to remember what it was like for them on day one. Thank goodness for the OLF!
Author:  Rod True [ Mon Mar 19, 2007 10:54 am ]
Post subject: 
The other thing you really want to make sure with the new brace Irwin is that the lap joint be as tight as you can get it, before gluing. You don't want the glue to fill any gaps. This way that joint will be as strong as possible, than as Michael indicated (and looks like you did on the first x-brace) cap the top.

As for the order of installation, I know that Joe mentioned to glue down the bridge patch first, which is how it's done in Cumpiano's book, but respectfully, I'll have to disagree with him. The bridge patch is a larger surface area and when you get that much glue on the large a surface area, the plate will want to float around more and be harder to hold in place while the glue sets up. Especially with go-bars wanting to push it around on the plate.

Here is how I do it. Glue down the "up" side lap joint brace first, with the other brace over top (without glue on it) to hold both braces in place. Than after 10 mins, take to go-bars off the unglued brace (the other brace should stay in place now) and glue it down. Than when the glue has set on both braces (1 hour at least, some would say 2-4 hrs) glue the cap on.

By gluing one brace at a time and using the other brace to help hold the position of the first, you can really get the brace in place accurately.

Clear as mud?
Author:  Irwin R [ Mon Mar 19, 2007 11:19 am ]
Post subject: 
That seems a good idea Rod...I cut my new brace last night and got  a nice tight fit..If I do as you suggest, wouldn't the force exerted to separate the braces after the first has set,to glue down # 2, be enough to potentially cause a problem?..I 'm feeling right now "that if it can go wrong... it will"
Author:  crazymanmichael [ Mon Mar 19, 2007 12:52 pm ]
Post subject: 
tight doesn't mean a forced press fit. if it's that tight when you put glue in the brace might swell and crack the other. but it should be sufficiently tight that there is no movement.
Author:  Irwin R [ Mon Mar 19, 2007 1:21 pm ]
Post subject: 
Thanks Michael...I do a little filing..it is a very tight fit...
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/