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| Redwood Jumbo top thickness? http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=25749 |
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| Author: | Geordie Adams [ Fri Jan 29, 2010 9:46 am ] |
| Post subject: | Redwood Jumbo top thickness? |
hi all I’ve got a nice stiff 20 year old Redwood top that I plan to use on my design project at college. The spec is 16 inch lower bout 12 fret to body cutaway, 25.4 scale. I’m thinking of using the Don MacRostie OOO sound hole and bracing placement 1/4W x 5/16H X brace as advised on the forum a while back. Question - given the above spec what top thickness would you guys be aiming for? and would it be OK to use 1/4W x 5/16H X on a 16 inch LB redwood. Its only my second build, my first is spruce so I don’t have a clue regarding Cedar or Redwood so any advice would be appreciated. regards Geordie |
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| Author: | Laurent Brondel [ Fri Jan 29, 2010 10:15 am ] |
| Post subject: | Re: Redwood Jumbo top thickness? |
On a 12 fret 16" lower bout guitar I'd use 5/16" wide bracing -at least for the X- and a taller at the apex than what you describe. I do not think anybody can answer your question without flexing your top. Usually redwood and WRC are left 10 to 15% thicker than a stiff spruce top. |
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| Author: | Tom West [ Fri Jan 29, 2010 10:51 am ] |
| Post subject: | Re: Redwood Jumbo top thickness? |
I also think you should use 5/16w bracing because I think Cedar and Redwood do not make as strong a glue joint as Spruce no doubt as a result of weaker wood fibers. I think 1/4w would be too narrow for this wood.Not sure what you are saying about 5/16h,but think you could get yourself in trouble quickly with insufficent height on your braces.Top thickness again depends on stiffness. Also Redwood is notoriously famous for spliting from trauma that would not make a spruce top's eyes blink.Have used both Cedar and Redwood and they do make nice guitars. Reread your question and may have gotten it wrong...! If you are saying 1/4wx5/16d for soundhole bracing only I think your OK. The first paragraph of advice is for your main bracing. Good luck and have fun. Tom |
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| Author: | Michael Dale Payne [ Fri Jan 29, 2010 2:02 pm ] |
| Post subject: | Re: Redwood Jumbo top thickness? |
1/4" x .3125 tall (5/16) bracing? For real??? way to short in my books. Heck that is almost square!!!! I would use 5/16 wide 5/8" or 3/4" tall on a medim to large body guitar. Heck I use 5/16 wide 3/4 tall on my OMs and 000s |
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| Author: | Geordie Adams [ Fri Jan 29, 2010 4:10 pm ] |
| Post subject: | Re: Redwood Jumbo top thickness? |
hi all Laurent, Tom & Michael many thanks for your suggestions, appreciated. I arrived at those figures via the input below, at that time I thought it would be alpine spruce I would be using for this build so here are some of the replies by fellow OLF's, I am aware redwood is less robust, hence the call for help. Quote: I don't see a problem with 1/4" braces on a 16" body. I would be more concerned with brace placement and 12 fret on a big body... Quote: I've used them for years . Just make sure the glue joints are perfect. They will weigh less than a 5/16" brace so keep that in mind when carving and their final height. Quote: My 16" lower bout Martin style Jumbo and the Wedge guitar based on the same outline both have 1/4" bracing, I start a little taller and tune them in. Both guitar sound real good and there are so far no issues, and I use the 12 to 56 light medium strings as I do a lot of lower tunings on the bass strings. I believe martin uses 1/4 bracing on the 3 pc back Dreadnought I think its the D35, I have seen some of them from the 70's and they are a little lifted behind the bridge but not enough to be a concern. Quote: If your X braces are going to be 1/4" wide, I would make them taller than 1/2". best regards Geordie |
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| Author: | Colin S [ Fri Jan 29, 2010 6:00 pm ] |
| Post subject: | Re: Redwood Jumbo top thickness? |
Geordie, on my Redwood OOO size guitar, 382mm (15") lower bout, I use my normal 6mm wide braces, with the X brace intersection at just less that 15mm, not including the cap. This has produced as good a sounding guitar across the board as I have built. Colin  
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| Author: | Geordie Adams [ Sat Jan 30, 2010 10:01 am ] |
| Post subject: | Re: Redwood Jumbo top thickness? |
Collin, thats just what I needed, data and pic's, I'll go with that bearing in mind what Laurent said re. thickness. I take it finger and tone bars will be "OOO" standard. many thanks and best regards Geordie |
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