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

Is top of soundboard supposed to be concave?
http://luthiersforum.com/forum/viewtopic.php?f=10101&t=42993		 Page 1 of 1
Author:  CalebW [ Mon Mar 17, 2014 8:32 pm ]
Post subject:  Is top of soundboard supposed to be concave?
I recieved my soundboard from LMI and they inlaid the rosette on the concave side of the sound board. Is this right?
Author:  Imbler [ Mon Mar 17, 2014 8:37 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
Caleb, it should be flat. It is probably just reacting to new humidity conditions at your location. Sticker it for a while at your conditions. (lay it on a couple of approx 1 by 1 inch boards, and place similar boards on the top of the soundboard over the lower boards with a little weight. This forces it flat while allowing equal humidity to reach each side.
Author:  theguitarwhisperer [ Mon Mar 17, 2014 8:56 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
The rosettes have the effect of "fixing" the wood in pace so that the wood around it doesn't react evenly to humidity changes.

If it's concave around the soundhole then the wood on the opposite side has expanded a little during shipping.

LMII stores their wood at 50% RH I believe, if your shop is at that RH then i would place the top on a flat surface concave side down until the top flattens out, then sticker it so air can circulate evenly around it and it should remain stable until it's braced.
Author:  CalebW [ Mon Mar 17, 2014 9:37 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
Ok thanks, the upper bout of the soundboard is flat so I was under the impression that the lower bout of the soundboard was supposed to be radiused to 25'(or so) and that the top of the lower bout was supposed to be convex.
Author:  theguitarwhisperer [ Tue Mar 18, 2014 12:40 am ]
Post subject:  Re: Is top of soundboard supposed to be concave?
CalebW wrote:
Ok thanks, the upper bout of the soundboard is flat so I was under the impression that the lower bout of the soundboard was supposed to be radiused to 25'(or so) and that the top of the lower bout was supposed to be convex.


Well, it depends on how you build, but normally an unbraced top should start out flat, and it attains the required dimensions a s a matter of being braced that way.

If you just received your top in the mail, be aware that it adjusted to the temperature and humidity of the shipping environment and will likely further react to your shop environment. Rosettes tend to have a fixating effect on the surrounding wood.
Author:  Clinchriver [ Tue Mar 18, 2014 4:51 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
Wood needs some time to achieve equilibrium in your shop turn the concave side down, it will reverse the curl , keep flipping until it stays flat.
Author:  John Arnold [ Tue Mar 18, 2014 9:58 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
The radius is achieved when you glue radiused braces to the top. Before that occurs, you can bend the top any way you choose.
Author:  CalebW [ Wed Mar 19, 2014 3:52 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
John Arnold wrote:
The radius is achieved when you glue radiused braces to the top. Before that occurs, you can bend the top any way you choose.

What is the usual radius for a cedar soundboard? 25'?
Author:  Hesh [ Wed Mar 19, 2014 3:55 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
The radius is up to you and what you want to impart to the top. 25' is a common one though.
Author:  theguitarwhisperer [ Wed Mar 19, 2014 4:39 pm ]
Post subject:  Re: Is top of soundboard supposed to be concave?
The radius is dependent on your overall design, so if you want a 25' radius, you need to adjust your neck angle and bridge thickness to match.
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/