Question about braces

[Thomas Erickson]

I'm wondering about braces in a flat back bass; I know it has been covered before on this forum, but I didn't find quite what I'm looking for -

I'd like to know what people are thinking in regard to the top brace and the break, for a bass that has one - should the brace always be placed directly over the break, to reinforce it? I've read suggestions that three braces is generally suitable; in this case, should the top brace still support the break even if that leaves a fairly good amount of the rest of the upper bout bare, or would it be better to locate it lower where it would cover more width (or add another brace)?

Thanks for any thoughts...

[Ken Smith]

Originally Posted by Thomas Erickson

I'm wondering about braces in a flat back bass; I know it has been covered before on this forum, but I didn't find quite what I'm looking for -

I'd like to know what people are thinking in regard to the top brace and the break, for a bass that has one - should the brace always be placed directly over the break, to reinforce it? I've read suggestions that three braces is generally suitable; in this case, should the top brace still support the break even if that leaves a fairly good amount of the rest of the upper bout bare, or would it be better to locate it lower where it would cover more width (or add another brace)?

Thanks for any thoughts...

In the case of a definite upper angle break and especially if the Back has a cut there I think a brace there acts as a support piece to avoid or prevent the angle break area to crack because they often do.

As far as how many braces or the style of bracing that depends on a few things which include the size of the bass, the condition of the back, the strength of the wood species, the thickness of the wood and in some cases the tone desired in replacing or modifying the current bracing system.

On my 4/4 Prescott when it was restored it got two upper braces with one on the break. The 7/8 Hart ended up with just one upper brace as that's all it needed. Two other more modern basses that were restored has the bracing system changed to a single modified X-system. The Mougenot I have is between a 7/8 and 4/4 by French standards and that has only the original single center wide Stair-step 8" wide center brace. The brace system during the back restoration will get a normal center brace, a lower bout brace and a single upper bout brace. The upper and lower being shaped like a Bass bar rather than the wide flat style too often used in many basses which add too much wood, weigh the bass down and choke a bit of sound in the process.

You basically have to guess what will work best in the Bass you are working on. The more you have seen, done, changed, altered and had success and failure with, the more you will know to equate what the current bass needs.

[Ken Smith]

On some of my basses that were restored, the angle break does NOT have a brace there. My Hart for one has Linen over the break and a few long vertical 'finger' patches over the joint in places. I think in this case it was determined than the Back was very strong and in near mint condition and didn't need any more wood added than necessary. It has a center brace of normal width and a lower brace shaped like a bass bar.

My Lott copy bass has a modified single 1/2 X style brace with a bass bar shaped piece opposite it on the bottom as well. The upper angle break has mainly just Linen across it.

I would have to put both of these up on the Bench to better map out and explain things. Also, my Panormo school bass which is a round back has spaced out Studs across its break point as did my previous owned attributed Dodd/Betts bass of which was pointed out to me 'done in the style of Panormo'.

All in all, there is NO standard way. Those that put 3, 4 or 5 braces in by measurement alone are just not thinking things over all the way. Depending on where you and your bass live, the bracing might need less support so that the Back can breathe and move a bit rather than having something come apart.

Consider the sound of the bass before the job, the strength and thickness of the back, its repairs and condition of them, the size of the bass including length of the bouts and their width and then just take a guess at what would be enough to hold it together and not too much so as to hamper its vibration of sound transfer. Unless you continuously do it over and over in several ways on the exact same bass and do nothing else each time but alter the braces, it would be impossible to tell what the differences are. Weigh your options and 'why' and choose a sensible method.

I have seen more ways to brace a back than I could list.

[Matthew Tucker]

if you build a slight convexity into the flatback - maybe only 4-6mm over the entire width, the break becomes very rigid and strong. After bending the break, I re-cut the kerf to give it straight sides then glue in a fillet of wood. so i dont think in this case a brace is necessary at that point. i would rather save weight and brace further down to give the back its convexity.

however if the break is old, damaged or frail, then a brace there is an obvious choice.

[Ken Smith]

Originally Posted by wayne holmes

for my 2cents-brace it--anything that will help it keep its shape -a break in the wood is going to be vulnerable to loose its shape and come apart as many do that I have seen-good luck-good question

The Angle Break at the top to loose its shape? I don't think there is much stress there at all. Mostly what I have seen is at the lower bouts on a flatback with the wider part of the wood is trying to breathe and when it moves, something somewhere gives.

I have never seen any problem develop in an upper Angle break within MY time. I have seen old basses with problems and repairs but I think it takes a long time or an accident for something to happen. If the wood is very thin or the break cut or bend poorly done or ill-supported than maybe it will fail sooner than later. This IS the original way Bass instruments were made as developed by D'Salo from the Viol.

On the original Posters question we are not totally sure if he is making a Bass and asking how to do the Back or fixing a Bass new or old. Of course making a bass, roundbacks of any arch from shallow to severe if done fairly well will see less problems over time than a flatback, period.

For me, I prefer a Roundback with low arch and a semi-center brace as well. In place of the angle break I prefer some type of gradual bend towards the neck. I don't see how cutting across the back for an upper bend is a good thing for the long hall regardless of how well its done.

[Adrian Levi]

Is it possible that the differences in sound between flat back vs round has to do more with the crossbars found on a flat ? I have often wondered about this seeing as so much importance is placed on the ribs and plates vibrating as freely as possible ....?

[Thomas Erickson]

Interesting stuff, thanks all for posting.

Originally Posted by Ken Smith

On the original Posters question we are not totally sure if he is making a Bass and asking how to do the Back or fixing a Bass new or old. Of course making a bass, roundbacks of any arch from shallow to severe if done fairly well will see less problems over time than a flatback, period.

Not building a bass yet; just got to wondering if the break was generally considered a weak point that should be reinforced from the get-go, or if placing a brace there is more a matter of routine and/or to solidify older basses that are weak or damaged.