Falcate bracing - bass back

Talk about musical instrument construction, setup and repair.

Moderators: kiwigeo, Jeremy D

Post Reply
User avatar
matthew
Blackwood
Posts: 1188
Joined: Mon Oct 08, 2007 1:16 pm
Location: Sydney, Inner West
Contact:

Falcate bracing - bass back

Post by matthew » Wed Jul 06, 2016 11:46 am

Faced with the carnage wrought on large instruments in the New York winter by the dryness from a combination of subzero temps and central heating, I recently had to come up with a new bracing system for my silver medal double bass that would allow the wood to move while providing stiffness and support for the soundpost. My bass back seam opened up last winter and actually split the end block, so i had to rebuild that as well as inserting a tapered insert down the full length of the back, and then remove all the original braces.

Double basses are either roundback (using no bracing) or flatback (using traditional "ladder" bracing or "X" bracing or variants thereof. But neither of these systems appealed to me, I'm not sure why. You can see some traces of the previous traditional lateral bracing system on the back.

So I had a chat to Trevor to bounce some ideas around, and after some thought, this is what I came up with.

I call it the boomerang bracing system and the design concept is "no crossgrain gluing over 45 degrees". Hence the cutaway at the apex of the lower boomerang. The idea is that the back wood (tassie blackwood) should be able to move as it needs in humid or dry conditions without popping a brace due to differential shrinkage, and if there is anything that needs to "give" it will be a side seam which is glued with a weaker hide glue as per usual practice for the top. The centre panel is to support the pressure of the soundpost and distribute this between the braced areas.
back bracing.jpg
13517492_10208805664412731_486678423865479637_o.jpg
The braces are laminated using West System and attached with hide glue. The diamond cleats are an established method of reinforcing seams.

The bass is back together and sounding even better than before. Bass response improved noticeably.

User avatar
kiwigeo
Admin
Posts: 10160
Joined: Sat Sep 29, 2007 5:57 pm
Location: Adelaide, Sth Australia

Re: Falcate bracing - bass back

Post by kiwigeo » Wed Jul 06, 2016 5:49 pm

The Gore army continues to grow.... :mrgreen:

Nice work Matthew....
Martin

blackalex1952
Blackwood
Posts: 777
Joined: Tue Aug 27, 2013 6:36 pm
Location: North East Victoria

Re: Falcate bracing - bass back

Post by blackalex1952 » Wed Jul 06, 2016 6:56 pm

Nice! The only problem I have is with the name of your bracing system...boomerangs return. So if the plan works, the bass should not return for repairs! :lol: Reminds me of the old gag "What do you call a boomerang that doesn't come back?...A stick!"
"Everything I say on the topic is based solely upon inexperience and assumption!"

User avatar
Nick
Blackwood
Posts: 3647
Joined: Thu Feb 26, 2009 11:20 am
Location: Christchurch, New Zealand
Contact:

Re: Falcate bracing - bass back

Post by Nick » Thu Jul 07, 2016 6:12 am

Elegant solution Matthew (and Trevor) and glad it has improved the sound rather than hindered.
"Jesus Loves You."
Nice to hear in church but not in a Mexican prison.

User avatar
Trevor Gore
Blackwood
Posts: 1553
Joined: Mon Jun 20, 2011 8:11 pm

Re: Falcate bracing - bass back

Post by Trevor Gore » Thu Jul 07, 2016 7:42 pm

Nice one, Matthew. Let's hope it doesn't get tortured quite as much this time around!

As the bass seems to sound better, is this going to become your standard back bracing? You could call it a triple bass... :roll:

User avatar
slowlearner
Blackwood
Posts: 386
Joined: Tue Jan 10, 2012 8:43 pm
Location: Western Sydney
Contact:

Re: Falcate bracing - bass back

Post by slowlearner » Fri Jul 08, 2016 2:08 pm

:shock:

Everytime I look, you guys are coming up with something new and awesome. 8)
Pete

User avatar
Graham Long
Blackwood
Posts: 141
Joined: Sat Feb 26, 2011 6:18 am
Contact:

Re: Falcate bracing - bass back

Post by Graham Long » Fri Jul 08, 2016 5:55 pm

Well done, that philosophy will come in handy elsewhere.
Did you still install it at around 45% RH?

User avatar
matthew
Blackwood
Posts: 1188
Joined: Mon Oct 08, 2007 1:16 pm
Location: Sydney, Inner West
Contact:

Re: Falcate bracing - bass back

Post by matthew » Fri Jul 08, 2016 10:44 pm

It was not possible to really control RH when I installed it. However, I kept the unbraced back in plastic with a pound of silica gel crystals before I glued it all up.

Post Reply

Who is online

Users browsing this forum: No registered users and 35 guests