French Bass Brace advice

[Ken Smith]

Matt, the work looks good.

Adrien, being that you can see the bass in person and we can't you have to decide the method of attack. Personally, I think a complete re-joint of the center with an even strip in the middle would look best and be the safest way to go. This way, you can trust the joint you made. If not and it fails again where you didn't touch it, then it's back to square one again. Do it once and do it good.

[Adrian Levi]

Originally Posted by Ken Smith

Matt, the work looks good.

Adrien, being that you can see the bass in person and we can't you have to decide the method of attack. Personally, I think a complete re-joint of the center with an even strip in the middle would look best and be the safest way to go. This way, you can trust the joint you made. If not and it fails again where you didn't touch it, then it's back to square one again. Do it once and do it good.

Thats exactly what Ill do , a complete re-joint .... Ill start early January and post pics etc

[Ken Smith]

What a bunch of confusing opinions I see here.

Ok, one single brace is not good.

Depending on the bass, it's size, your climate and what tone you want you can go with just about anything that works but a single wide center brace like you just took out. Also, there is little advantage if any making the smaller center brace out of the wide one you just removed. If you can, do it for the enjoyment. In that case you will need one across the lower bout and upper bout on the average. I think 3 or 4 braces with two uppers is quite normal but that depends on the back itself. I have seen as few as 2 and as many as 5 on the back braces (or 1 in the case of French basses). Again, take a chance and do what looks good for you in your mind, the bass itself and the climate it will live in. The X-system is a choice in some cases depending on all of the above as well and in that, there are a few ways to do the X. Two pieces with a lap joint, 3 pieces with no joint, one angled piece with a separate lower bar type cross angled or what ever the bass needs in your mind. Other than the center brace, the other braces should be shaped more like bassbars and not flat wide pieces, I think!


Have fun. The restorers that have repaired the most backs successfully will have the best advice in my opinion. Nothing is ever easy with a flatback. You have the birdseye view of the back in question to decide how much support it needs to work and how much to let it breathe.

I have had and played basses with just about every kind of back out there, well most of them. You don't know whats best without changing things and living with it for a decade each way. The back vibrating is not a problem. Even the scroll vibrates. My Gilkes was as loud from the back as it was in front. The Sound post will make it vibrate but the top should float more than the back. Don't get too technical here in the mind. Repair it sensibly and go play the bass, That's part of the recovery, the playing in of a restored bass.

[Adrian Levi]

[quote=Ken Smith;21709]What a bunch of confusing opinions I see here.

[quote]Have fun. The restorers that have repaired the most backs successfully will have the best advice in my opinion. Nothing is ever easy with a flatback. You have the birdseye view of the back in question to decide how much support it needs to work and how much to let it breathe.

I like the fun part , and the excitement of the unknown / Im going with the 3 braces.

[Ken Smith]

[QUOTE I like the fun part , and the excitement of the unknown / Im going with the 3 braces.[/quote]

My Mougenot is about as French as it gets as far as the Tradition goes. Full sized Vuillaume model (7/8th by our standards), flatback and it had a single wide center brace. Like my Hart bass, the back never cracked but opened up in the center seam, 3/4's its length, both basses. The Hart has a very stiff & strong back so it got a center and lower brace only and studs and linen I recall at the angle break ( I will have to look inside to make sure). The Mougenot is still on Jeff's bench getting the C-extension but I think we agreed on 3 or 4 braces, 1 or 2 upper (I will have to look as I forgot what we discussed). French basses usually bend gradually from the upper corner block and never a direct angle break. Both basses got an added center strip most of the way up which is a good thing because it shows that rather then the back splitting over time, the center just opened which looks much better repaired than a bunch of back splits.

So, depending on the length of the back, just the upper bout in the center would be fine unless the back is thin and needs more support. Like I said in my last post, you have the best view of this and must decide what it needs.

[Adrian Levi]

The ribs are now as clean as I'm going to get them without doing more damage to the damage.It seems as if the bass was about 50% wood and 50% epoxy.
The one lower bout is the only one left to reinforce . The other lower bout with the repairs was less than 1 mm in places and still needs the back edging to be replaced.
Now that the two pieces of back are flattened and ready to plane for an insert I'm not quite sure how to figure the exact size that the insert should be.
The back has shrunk a fair amount and to compensate the ribs were force epoxied in. The freed rib structure now spans about 20 mm more in its relaxed state.
Is it a matter now of lying the rib structure on top of the back to measure the space needed for insert ?
Or is it better to measure the back against the top for size ....?

[Ken Smith]

Looks good. I would suggest fitting the Top first since it is the least flexible part and prone to cracking. The Back can be widened as needed but dry fit and estimate it first before making the center spline/insert.

[Adrian Levi]

Originally Posted by Ken Smith

Looks good. I would suggest fitting the Top first since it is the least flexible part and prone to cracking. The Back can be widened as needed but dry fit and estimate it first before making the center spline/insert.

That makes total sense and I just sat the top on the rib assembly and it is a perfect fit .I was worried that I may have to cut the ribs down to accommodate the top.

[Matthew Tucker]

Wayne, how on earth can X braces be an easy way out?

[Matthew Tucker]

Originally Posted by wayne holmes

seriously, less cutting, less thought, less everything, less clamping, less coverage of the middle seam, lesser number of pieces, less measuring,less amount of wood crossing the middle seam, less confusion- less time, less creativity, shall I continue? less balance and support of structure- less lipstick!

Would you be happier with far simpler lattice bracing perhaps??

[Arnold Schnitzer]

Originally Posted by Matthew Tucker

Would you be happier with far simpler lattice bracing perhaps??

Nice! But just a bit too much glue for my taste...

Adrian, I agree with the 3 brace technique. Keep them away from the linings, and feather the ends after the glue is cured. Glue it all up when climate conditions in your shop are toward the dry side. Use a caul on the outside of the back under each brace as you glue up. Good luck!